CD40
Tumor necrosis factor receptor superfamily member 5 precursor (B-cell surface antigen CD40) (Bp50) (CD40L receptor) (CDw40) (CD40 antigen) [TNFRSF5]
Publications[править]
Aging is associated with an increased incidence of cancer. One contributing factor could be modulation of immune cells responsible for anti-tumor responses, such as dendritic cells (DCs) and T cells. These immunological changes may also impact the efficacy of cancer immunotherapies in the elderly. The effects of healthy aging on DCs and T cells, and their impact on anti-mesothelioma immune responses, had not been reported. This study examined DCs and T cells in young (2-5 months; equivalent to 16-26 human years) and elderly (20-24 months; equivalent to 60-70 human years) healthy and mesothelioma-bearing C57BL/6J mice. During healthy aging, elderly lymph nodes adopted a regulatory profile, characterized by: (i) increased plasmacytoid DCs, (ii) increased expression of the adenosine-producing enzyme CD73 on CD11c cells, and (iii) increased expression of multiple regulatory markers (including CD73, the adenosine A2B receptor, CTLA-4, PD-1, ICOS, LAG-3, and IL-10) on CD8 and CD4 T cells, compared to lymph nodes from young mice. Although mesotheliomas grew faster in elderly mice, the increased regulatory status observed in healthy elderly lymph node DCs and T cells was not further exacerbated. However, elderly tumor-bearing mice demonstrated reduced MHC-I, MHC-II and CD80 on CD11c cells, and decreased IFN-γ by CD8 and CD4 T cells within tumors, compared to young counterparts, implying loss of function. An agonist CD40 antibody based immunotherapy was less efficient at promoting tumor regression in elderly mice, which may be due to: (i) failure of elderly CD8 T cells to up-regulate perforin, and (ii) increased expression of multiple regulatory markers on CD11c cells and T cells in elderly tumor-draining lymph nodes (including CD73, PD-1, ICOS, LAG-3, and TGF-β). Our findings suggest that checkpoint blockade may improve responses to immunotherapy in elderly hosts with mesothelioma, and warrants further investigation.
Keywords
- aging
- cancer
- dendritic cells
- immunosuppression
- immunotherapy
One hundred and twenty one-day-old breeder cocks, included 15 cages of 8 birds each, were fed to learn the aging's effect on chicken's thymus immunity. At 2 (2-W) and 40 (40-W) weeks of age, one chicken each cage was randomly chosen and slaughtered to get the thymus sample. The results showed that thymus weight and morphology of 40-W group were far different from that of 2-W group, and exhibited a property of degeneration. Considering this phenotype variance, we analyzed the thymus' transcriptome to investigate the molecular mechanism that had been implicated in this phenotype diversity with age. Pearson correlation coefficients and principal component analysis indicated that two major populations corresponding to 40-W and 2-W group were identified, and 1949 differentially expressed genes (DEGs, 1722 up-regulated and 127 down-regulated) were obtained. Results of GO and KEGG pathway enrichment found that 4 significantly enriched KEGG pathways (Cytokine-cytokine receptor interaction, Intestinal immune network for IgA production, Toll-like receptor signaling pathway, AGE-RAGE signaling pathway in diabetic complications) related to immunoregulation were screened between 40-W and 2-W group. These results confirmed that thymus immunity of chickens had a strong age-related correlation. DEGs related to these 4 enriched KEGG pathways were suppressed in the thymus of 2-W group, this indicated that thymus immunity of 2-weeks-age chick was down-regulated. CD40 is involved in 3 of the 4 significantly enriched pathways, and it is critical for thymus immune-regulation. CD40 promoter methylation level of 2-W group was higher than that of 40-W group, it is consistent with the transcriptional differences of the gene. Our study concluded that thymus immunity of chicken was varied with age. Compared to the 40-W group, thymus immunity of 2-W group was down-regulated, and in a status of hypo-activation on the whole, and these effects might be related to CD40 suppression induced by promoter hyper-methylation of the gene.
MeSH Terms
- Aging
- Animals
- Avian Proteins
- CD40 Antigens
- Chickens
- DNA Methylation
- Gene Expression Regulation
- Promoter Regions, Genetic
- Thymus Gland
Keywords
- CD40
- DNA methylation
- age
- chicken
- thymus immunity
Most cancers emerge in the elderly, including lung cancer and mesothelioma, yet the elderly remain an underrepresented population in pre-clinical cancer studies and clinical trials. The immune system plays a critical role in the effectiveness of many anti-cancer therapies in young hosts via tumor-specific T cells. However, immunosuppressive macrophages can constitute up to 50% of the tumor burden and impair anti-tumor T cell activity. Altered macrophage phenotype and function during aging may further impact anti-tumor T cell responses. Yet, the impact of macrophages on anti-tumor T cell responses and immunotherapy in the elderly is unknown. Therefore, we examined macrophages and their interaction with T cells in young (3 months) and elderly (20-24 months) AE17 mesothelioma-bearing female C57BL/6J mice during tumor growth. Mesothelioma tumors grew faster in elderly compared with young mice, and this corresponded with an increase in tumor-associated macrophages. During healthy aging, macrophages increase in bone marrow and spleens suggesting that these sites have an increased potential to supply cancer-promoting macrophages. Interestingly, in tumor-bearing mice, bone marrow macrophages increased proliferation whilst splenic macrophages had reduced proliferation in elderly compared with young mice, and macrophage depletion using the F4/80 antibody slowed tumor growth in young and elderly mice. We also examined responses to treatment with intra-tumoral IL-2/anti-CD40 antibody immunotherapy and found it was less effective in elderly (38% tumor regression) compared to young mice (90% regression). Tumor-bearing elderly mice decreased [i]in vivo[/i] anti-tumor cytotoxic T cell activity in tumor draining lymph nodes and spleens. Depletion of macrophages using F4/80 antibody in elderly, but not young mice, improved IL-2/anti-CD40 immunotherapy up to 78% tumor regression. Macrophage depletion also increased [i]in vivo[/i] anti-tumor T cell activity in elderly, but not young mice. All the tumor-bearing elderly (but not young) mice had decreased body weight (i.e., exhibited cachexia), which was greatly exacerbated by immunotherapy; whereas macrophage depletion prevented this immunotherapy-induced cachexia. These studies strongly indicate that age-related changes in macrophages play a key role in driving cancer cachexia in the elderly, particularly during immunotherapy, and sabotage elderly anti-tumor immune responses.
Keywords
- T cells
- aging
- cachexia
- cancer
- immunotherapy
- macrophage
Amongst the major features of aging are chronic low grade inflammation and a decline in immune function. The Mediterranean diet (MedDiet) is considered to be a valuable tool to improve health status, and although beneficial effects have been reported, to date, immunological outcomes have not been extensively studied. We aimed to test the hypothesis that 1 year of a tailored intervention based on the MedDiet with vitamin D (10 μg/day) would improve innate immune responses in healthy elderly subjects (65-79 years) from the English cohort (272 subjects recruited) of the NU-AGE randomized, controlled study (clinicaltrials.gov, NCT01754012). Of the 272 subjects forming the United Kingdom cohort a subgroup of 122 subjects (61 in the intervention group and 61 in the control group) was used to evaluate [i]ex vivo[/i] innate immune response, phenotype of circulating immune cells, and levels of pro- and anti-inflammatory markers. Odds Ratio (OR) was calculated for all the parameters analyzed. After adjustment by gender, MedDiet-females with a BMI < 31 kg/m had a significant upregulation of circulating CD40 CD86 cells (OR 3.44, 95% CI 1.01-11.75, [i]P[/i] = 0.0437). Furthermore, in all MedDiet subjects, regardless of gender, we observed a MedDiet-dependent changes, although not statistically significant of immune-critical parameters including T cell degranulation, cytokine production and co-receptor expression. Overall, our study showed that adherence to an individually tailored Mediterranean-like dietary pattern with a daily low dose of vitamin D3 supplements for 1 year modified a large variety of parameters of immune function in healthy, elderly subjects. We interpreted these data as showing that the MedDiet in later life could improve aspects of innate immunity and thus it could aid the design of strategies to counteract age-associated disturbances. clinicaltrials.gov, NCT01754012.
Keywords
- NU-AGE
- aging
- dietary intervention
- elderly
- inflammation
- nutrition
Cellular senescence acts as a barrier against tumorigenesis. The CD40L transgene, expressed in some tumor cells, not only becomes visible to antigen-presenting cells but also actively catalyzes its own termination. Here, we evaluated the effect of a membrane-bound mutant form of human CD40L (CD40L-M) on senescence and the senescence-associated secretory phenotype (SASP) in non-small cell lung cancer (NSCLC). CD40 expression levels in the NSCLC cell lines A549/TR, A549/DDP and H460 were examined by flow cytometry. Senescent cells and tissues were identified via SA-β-gal activity. Cell proliferation was visualized by EdU labeling. qRT-PCR, Western blotting, and immunofluorescence staining were conducted to assess mRNA and protein expression levels of CD40L, γ-H2A.X, p65, p-p65, IκBα, p53, p21 and p16. Cytokines secreted from transfected cells were tested by ELISA and cell migration assay. Capsid tyrosine-modified rAAV5-CD40L-M was packaged and carried out in vivo. Overexpression of CD40L-M promoted senescence, inhibited proliferation, increased DNA damage-associated γ-H2A.X, and initiated the SASP in CD40-positive NSCLC cells. NF-κB signaling was activated by CD40L-M overexpression in these cells. Knockdown of NF-κB partially overcame senescence and failed to induce SASP. Furthermore, increased p53 and p21 protein levels induced by CD40L-M were also reduced following NF-κB suppression. These data showed that the membrane-bound CD40L mutant may promote cellular senescence and initiate the SASP of NSCLC cells in an NF-κB-dependent manner. Therefore, CD40L-M-induced senescence may be a potential approach to protect against lung adenocarcinoma.
MeSH Terms
- Adenocarcinoma
- Adenocarcinoma of Lung
- Animals
- Antineoplastic Agents, Phytogenic
- CD40 Ligand
- Cell Line, Tumor
- Cell Proliferation
- Cellular Senescence
- Cyclin-Dependent Kinase Inhibitor p21
- Histones
- Humans
- I-kappa B Proteins
- Lung Neoplasms
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Nude
- NF-kappa B
- Paclitaxel
- RNA Interference
- RNA, Small Interfering
- Tumor Suppressor Protein p53
Keywords
- Cd40l mutant
- Lung adenocarcinoma
- NF-κB
- SASP
- Senescence
Immunosenescence is a remodeling of the immune system, caused by aging, with changes in the function of neutrophils, lymphocytes, and Treg cells. This study aimed to evaluate the expression of molecules CD11b, CD16 and CD64 (neutrophils), CD154 (T lymphocytes), CD40 (B lymphocytes), and to quantitatively analyze the Treg cell subpopulation. 49 elderlies (≥60 years) and 49 adults (≤35 years) were studied. Flow cytometry was used to analyze the expression of surface molecules and the subpopulation of Treg cells, and the results between the groups were compared statistically by the t-test. There was a decreased significance in the expression of CD11b and CD40 in the elderly. Decreased CD11b expression can result in susceptibility to infectious diseases, and impairment of phagocytic capacity. Decreased CD40 expression can result in a decline in B lymphocyte activation. The other molecule studied presented alterations not significant, but compatible with the immunological changes in aging.
MeSH Terms
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- B-Lymphocytes
- Biomarkers
- Brazil
- CD11b Antigen
- CD40 Antigens
- CD40 Ligand
- Cellular Senescence
- Cross-Sectional Studies
- Down-Regulation
- Female
- Flow Cytometry
- GPI-Linked Proteins
- Humans
- Immunophenotyping
- Immunosenescence
- Lymphocytes
- Male
- Middle Aged
- Neutrophils
- Receptors, IgG
- T-Lymphocytes, Regulatory
- Young Adult
Keywords
- CD11b
- CD40
- Immunosenescence
- aging
- lymphocytes
- neutrophils.
Pseudomonas aeruginosa (PS) infection results in severe morbidity and mortality, especially in immune-deficient populations. Aerobic exercise (AE) modulates the immune system, but its effects on the outcomes of pulmonary PS infection in elderly mice are unknown. BALB/c mice (24 weeks old) were randomized to sedentary, exercise (EX), PS, and PS EX groups for the acute experimental setting, and PS and PS EX groups for the chronic setting. Low-intensity AE was performed for 5 weeks, 60 min/day; 24 h after the final AE session, mice were inoculated with 5 × 104 colony-forming units (CFU) of PS, and 24 h and 14 days after PS inoculation, mice were studied. AE inhibited PS colonization (p < 0.001) and lung inflammation (total cells, neutrophils, lymphocytes [p < 0.01] in bronchoalveolar lavage [BAL]), with significant differences in BAL levels of IL-1β (p < 0.001), IL-6 (p < 0.01), CXCL1 (p < 0.001), and TNF-α (p < 0.001), as well as parenchymal neutrophils (p < 0.001). AE increased BAL levels of IL-10 and parenchymal (p < 0.001) and epithelial (p < 0.001) IL-10 expression, while epithelial (p < 0.001) and parenchymal (p < 0.001) NF-κB expression was decreased. AE diminished pulmonary lipid peroxidation (p < 0.001) and increased glutathione peroxidase (p < 0.01). Pre-incubation of BEAS-2B with IL-10 inhibited PS-induced epithelial cell expression of TNF-α (p < 0.05), CD40 (p < 0.01), and dichlorodihydrofluorescein diacetate (p < 0.05). AE inhibits PS-induced lung inflammation and bacterial colonization in elderly mice, involving IL-10/NF-κB, and redox signaling.
MeSH Terms
- Aging
- Animals
- Disease Models, Animal
- Exercise
- Glutathione Peroxidase
- Humans
- Interleukin-10
- Lipid Peroxidation
- Lung
- Mice
- Mice, Inbred BALB C
- NF-kappa B
- Neutrophils
- Physical Conditioning, Animal
- Pneumonia
- Pseudomonas Infections
- Pseudomonas aeruginosa
- Signal Transduction
Keywords
- Cytokines
- Elderly
- Exercise immunology
- Physical training
- Pseudomonas
There is evidence that dendritic cells (DCs) undergo age-related changes that modulate their function with their key role being priming antigen-specific effector T cells. This occurs once DCs develop into antigen-presenting cells in response to stimuli/danger signals. However, the effects of aging on DC responses to bacterial lipopolysaccharide (LPS), the pro-inflammatory cytokine interferon (IFN)-γ and CD40 ligand (CD40L) have not yet been systematically evaluated. We examined responses of blood myeloid (m)DC1s, mDC2s, plasmacytoid (p)DCs, and monocyte-derived DCs (MoDCs) from young (21-40 years) and elderly (60-84 years) healthy human volunteers to LPS/IFN-γ or CD40L stimulation. All elderly DC subsets demonstrated comparable up-regulation of co-stimulatory molecules (CD40, CD80 and/or CD86), intracellular pro-inflammatory cytokine levels (IFN-γ, tumour necrosis factor (TNF)-α, IL-6 and/or IL-12), and/or secreted cytokine levels (IFN-α, IFN-γ, TNF-α, and IL-12) to their younger counterparts. Furthermore, elderly-derived LPS/IFN-γ or CD40L-activated MoDCs induced similar or increased levels of CD8 and CD4 T cell proliferation, and similar T cell functional phenotypes, to their younger counterparts. However, elderly LPS/IFN-γ-activated MoDCs were unreliable in their ability to up-regulate chemokine (IL-8 and monocyte chemoattractant protein (MCP)-1) and IL-6 secretion, implying an inability to dependably induce an inflammatory response. A key age-related difference was that, unlike young-derived MoDCs that completely lost their ability to process antigen, elderly-derived MoDCs maintained their antigen processing ability after LPS/IFN-γ maturation, measured using the DQ-ovalbumin assay; this response implies incomplete maturation that may enable elderly DCs to continuously present antigen. These differences may impact on the efficacy of anti-pathogen and anti-tumour immune responses in the elderly.
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Aging
- Antigens, CD1
- B7-2 Antigen
- CD40 Antigens
- CD40 Ligand
- Dendritic Cells
- Female
- Humans
- Lipopolysaccharides
- Male
- Middle Aged
- Transforming Growth Factor beta
- Young Adult
C-reactive protein (CRP) is the prototypical acute phase reactant, increasing in blood concentration rapidly and several-fold in response to inflammation. Recent evidence indicates that CRP has an important physiological role even at low, baseline levels, or in the absence of overt inflammation. For example, we have shown that human CRP inhibits the progression of experimental autoimmune encephalomyelitis (EAE) in CRP transgenic mice by shifting CD4 T cells away from the T 1 and toward the T 2 subset. Notably, this action required the inhibitory Fcγ receptor IIB (FcγRIIB), but did not require high levels of human CRP. Herein, we sought to determine if CRP's influence in EAE might be explained by CRP acting on dendritic cells (DC; antigen presenting cells known to express FcγRIIB). We found that CRP (50 µg/ml) reduced the yield of CD11c bone marrow-derived DCs (BMDCs) and CRP (≥5 μg/ml) prevented their full expression of major histocompatibility complex class II and the co-stimulatory molecules CD86 and CD40. CRP also decreased the ability of BMDCs to stimulate antigen-driven proliferation of T cells [i]in vitro[/i]. Importantly, if the BMDCs were genetically deficient in mouse FcγRIIB then (i) the ability of CRP to alter BMDC surface phenotype and impair T cell proliferation was ablated and (ii) CD11c-driven expression of a human [i]FCGR2B[/i] transgene rescued the CRP effect. Lastly, the protective influence of CRP in EAE was fully restored in mice with CD11c-driven human FcγRIIB expression. These findings add to the growing evidence that CRP has important biological effects even in the absence of an acute phase response, i.e., CRP acts as a tonic suppressor of the adaptive immune system. The ability of CRP to suppress development, maturation, and function of DCs implicates CRP in the maintenance of peripheral T cell tolerance.
MeSH Terms
- Animals
- C-Reactive Protein
- CD11c Antigen
- Cell Differentiation
- Cell Proliferation
- Cells, Cultured
- Dendritic Cells
- Disease Models, Animal
- Encephalomyelitis, Autoimmune, Experimental
- Humans
- Lymphocyte Activation
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Multiple Sclerosis
- Peripheral Tolerance
- Receptors, IgG
Keywords
- acute phase response
- aging
- autoimmunity
- inflammaging
- inflammation
- transgenic
Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder, caused by mutations in the dystrophin gene, affecting 1:3500-5000 boys worldwide. The lack of dystrophin induces degeneration of muscle cells and elicits an immune response characterized by an intensive secretion of pro-inflammatory cytokines. Immunoglobulins modulate the inflammatory response through several mechanisms and have been widely used as an adjuvant therapy for autoimmune diseases. Here we evaluated the effect of immunoglobulin G (IG) injected intraperitoneally in a severely affected double knockout (dko) mouse model for Duchenne muscular dystrophy. The IG dko treated mice were compared regarding activity rates, survival and histopathology with a control untreated group. Additionally, dendritic cells and naïve lymphocytes from these two groups and WT mice were obtained to study in vitro the role of the immune system associated to DMD pathophysiology. We show that IG therapy significantly enhances activity rate and lifespan of dko mice. It diminishes muscle tissue inflammation by decreasing the expression of costimulatory molecules MHC, CD86 and CD40 and reducing Th1-related cytokines IFN-γ, IL-1β and TNF-α release. IG therapy dampens the effector immune responses supporting the hypothesis according to which the immune response accelerates DMD progression. As IG therapy is already approved by FDA for treating autoimmune disorders, with less side-effects than currently used glucocorticoids, our results may open a new therapeutic option aiming to improve life quality and lifespan of DMD patients.
MeSH Terms
- Animals
- Cells, Cultured
- Cytokines
- Dendritic Cells
- Dystrophin
- Humans
- Immunoglobulin G
- Immunotherapy
- Injections, Intraperitoneal
- Longevity
- Lymphocytes
- Mice
- Mice, Inbred mdx
- Muscular Dystrophy, Duchenne
- Phenotype
- Utrophin
The origin and nature of age-associated B cells (ABCs) in mice are poorly understood. In this article, we show that their emergence required MHC class II and CD40/CD40L interactions. Young donor B cells were adoptively transferred into congenic recipients and allowed to remain for 1 mo in the absence of external Ag. B cells expressing the T-bet transcription factor, a marker for ABCs, were generated after multiple cell divisions from C57BL/6 donors but not from MHC class II- or CD40-deficient donors. Furthermore, old CD154 (CD40L)-deficient mice did not accrue ABCs, confirming that they arise primarily through T-dependent interactions. To determine what Igs ABCs express, we sequenced V and Vκ rearranged genes from unimmunized 22-mo-old C57BL/6 mice and showed that they had a heterogeneous repertoire, which was comparable to that seen in old follicular and marginal zone B cell subsets. However, in contrast to the follicular and marginal zone cells, ABCs displayed significant somatic hypermutation. The mutation frequency was lower than found in germinal center cells after deliberate immunization, suggesting that ABCs have undergone mild stimulation from endogenous Ags over time. These observations show that quiescent ABCs are Ag-experienced cells that accumulate during T cell-dependent responses to diverse Ags during the life of an individual.
MeSH Terms
- Aging
- Animals
- B-Lymphocyte Subsets
- CD40 Antigens
- Gene Rearrangement
- Genes, MHC Class II
- Germinal Center
- Lymphocyte Activation
- Mice
- Mice, Inbred C57BL
- Sequence Analysis, DNA
- Single-Domain Antibodies
- Somatic Hypermutation, Immunoglobulin
Autoantibodies can be present years to decades before the onset of disease manifestations in autoimmunity. This finding suggests that the initial autoimmune trigger involves a peripheral lymphoid component, which ultimately drives disease pathology in local tissues later in life. We show that Sjögren's syndrome manifestations that develop in aged NOD.H-2h4 mice were driven by and dependent on peripheral dysregulation that arose in early life. Specifically, elimination of spontaneous germinal centers in spleens of young NOD.H-2h4 mice by transient blockade of CD40 ligand (CD40L) or splenectomy abolished Sjögren's pathology of aged mice. Strikingly, a single injection of anti-CD40L at 4 weeks of age prevented tertiary follicle neogenesis and greatly blunted the formation of key autoantibodies implicated in glandular pathology, including anti-muscarinic receptor antibodies. Microarray profiling of the salivary gland characterized the expression pattern of genes that increased with disease progression and showed that early anti-CD40L greatly repressed B cell function while having a broader effect on multiple biological pathways, including interleukin-12 and interferon signaling. A single prophylactic treatment with anti-CD40L also inhibited the development of autoimmune thyroiditis and diabetes in NOD.H-2h4 and nonobese diabetic mice, respectively, supporting a key role for CD40L in the pathophysiology of several autoimmune models. These results strongly suggest that early peripheral immune dysregulation gives rise to autoimmune manifestations later in life, and for diseases predated by autoantibodies, early prophylactic intervention with biologics may prove efficacious.
MeSH Terms
- Aging
- Animals
- Antibodies, Monoclonal
- Autoantibodies
- Autoimmunity
- Bone Marrow Cells
- CD40 Antigens
- CD40 Ligand
- Cytokines
- Diabetes Mellitus, Experimental
- Disease Models, Animal
- Female
- Immune System
- Ligands
- Lymphocytes
- Mice
- Mice, Inbred NOD
- Salivary Glands
- Sjogren's Syndrome
- Spleen
- Thyroiditis, Autoimmune
The impact of infiltration of macrophages into the brain is debatable with evidence of both beneficial and detrimental effects. Recent work suggests that inflammatory macrophages, with an inflammatory phenotype that resembles the M1 activation state, may be detrimental, whereas anti-inflammatory M2-like macrophages may be beneficial. We set up a model to examine the response of bone marrow-derived macrophages to the inflammatory milieu that occurs in the aged brain. Expression of MHCII and CD40 was increased in macrophages incubated with soluble brain extract prepared from aged, compared with young, mice and this was accompanied by increased production of tumor necrosis factor-α and interleukin-6. Analysis of soluble brain extract indicated that it contained increased concentrations of several inflammatory mediators and, importantly, when bone marrow-derived macrophages were incubated in the inflammatory cytokines that were increased and applied to hippocampal slices, long-term potentiation was inhibited. The data suggest that infiltrating macrophages respond to local conditions and, in the case of aging, adopt an inflammatory phenotype that ultimately has a neurodetrimental effect.
MeSH Terms
- Aging
- Animals
- Brain
- Cells, Cultured
- Cytokines
- Inflammation Mediators
- Macrophage Activation
- Macrophages
- Male
- Mice, Inbred C57BL
- Neuronal Plasticity
- Synapses
Keywords
- Age
- Bone marrow–derived macrophages
- Inflammatory cytokines
- Microglia
- Synaptic plasticity
Immune-checkpoint blockade therapy with antibodies targeting CTLA-4 and PD-1 has revolutionized melanoma treatment by eliciting responses that can be remarkably durable and is now advancing to other malignancies. However, not all patients respond to immune-checkpoint inhibitors. Extensive preclinical evidence suggests that combining immune-checkpoint inhibitors with other anti-cancer treatments can greatly improve the therapeutic benefit. The first clinical success of the combinatorial approach to cancer immunotherapy was demonstrated using a dual-checkpoint blockade with CTLA-4 and PD-1 inhibitors, which resulted in accelerated FDA approval of this therapeutic regimen. In this review, we discuss the combinations of current and emerging immunotherapeutic agents in clinical and preclinical development and summarize the insights into potential mechanisms of synergistic anti-tumor activity gained from animal studies. These promising combinatorial partners for the immune-checkpoint blockade include therapeutics targeting additional inhibitory receptors of T cells, such as TIM-3, LAG-3, TIGIT, and BTLA, and agonists of T cell costimulatory receptors 4-1BB, OX40, and GITR, as well as agents that promote cancer cell recognition by the immune system, such as tumor vaccines, IDO inhibitors, and agonists of the CD40 receptor of APCs. We also review the therapeutic potential of regimens combining the immune-checkpoint blockade with therapeutic interventions that have been shown to enhance immunogenicity of cancer cells, including oncolytic viruses, RT, epigenetic therapy, and senescence-inducing therapy.
MeSH Terms
- Animals
- Antineoplastic Combined Chemotherapy Protocols
- Humans
- Immunologic Factors
- Immunotherapy
- Neoplasms
Keywords
- immune checkpoints
- immunogenic cell death
- melanoma
- senescence
Mesothelioma is an almost invariably fatal tumor with chemotherapy extending survival by a few months. One immunotherapeutic strategy is to target dendritic cells (DCs), key antigen-presenting cells involved in antigen presentation, to induce antigen-specific T cell responses. However, DC-targeting will only be effective if DCs are fit-for-purpose, and the functional status of DCs in mesothelioma patients was not clear. We found that mesothelioma patients have significantly decreased numbers of circulating myeloid (m)DC1 cells, mDC2 cells and plasmacytoid (p)DCs relative to healthy age and gender-matched controls. Blood monocytes from patients could not differentiate into immature monocyte-derived DCs (MoDCs), indicated by a significantly reduced ability to process antigen and reduced expression of costimulatory (CD40, CD80 and CD86) and MHC (HLA-DR) molecules, relative to controls. Activation of mesothelioma-derived MoDCs with LPS /-IFNγ generated partially mature MoDCs, evident by limited upregulation of the maturation marker, CD83, and the costimulatory markers. Attempts to rescue mesothelioma-derived DC function using CD40Ligand(L) also failed, indicated by maintenance of antigen-processing capacity and limited upregulation of CD40, CD83, CD86 and HLA-DR. These data suggest that mesothelioma patients have significant numerical and functional DC defects and that their reduced capacity to process antigen and reduced expression of costimulatory molecules could induce anergized/tolerized T cells. Nonetheless, survival analyses revealed that individuals with mesothelioma and higher than median levels of mDC1s and/or whose MoDCs matured in response to LPS, IFNγ or CD40L lived longer, implying their selection for DC-targeting therapy could be promising especially if combined with another treatment modality.
Keywords
- Aging
- CD40Ligand
- Mesothelioma
- immunotherapy
- myeloid dendritic cells
- plasmacytoid dendritic cells
- survival outcomes
Secondary necrotic cells, which are generated if apoptotic cells are incompletely cleared, induce severe inflammatory responses involving MIP-2 production and subsequent neutrophil infiltration. Recently, we showed that the phagocytic capacity of peritoneal resident macrophages from wild type (WT) aged mice as well as SMP30(-/-) mice fed a VC-limited diet as to secondary necrotic cells was reduced as compared with that in young mice, and that the inflammatory responses induced were stronger than those in young mice, presumably because of the delay in removal of secondary necrotic cells in aged mice. In this study, we investigated why MIP-2 production was increased in aged mice upon injection of secondary necrotic cells and why the phagocytic capacity of peritoneal resident macrophages from aged mice was reduced. When cocultured with secondary necrotic cells, the peritoneal resident macrophages from both types of aged mice significantly produced MIP-2 even in the absence of IFN-γ, whereas MIP-2 production by macrophages from WT young mice required IFN-γ. The peritoneal resident macrophages from both types of aged mice expressed CD40, a M1 macrophage marker, as in the case of M1 macrophages, which were obtained by treatment of macrophages from WT young mice with IFN-γ and LPS. Furthermore, M1 macrophages exhibited less phagocytic capacity as to secondary necrotic cells than non-treated macrophages. These results suggest that the phenotype of peritoneal resident macrophages is skewed toward M1-like in aged mice and that such skewing toward M1-like is involved in enhancement of inflammatory responses induced by secondary necrotic neutrophils in aged mice.
MeSH Terms
- Aging
- Animals
- CD40 Antigens
- Calcium-Binding Proteins
- Cell Differentiation
- Cells, Cultured
- Chemokine CXCL2
- Coculture Techniques
- Cytophagocytosis
- Inflammation
- Interferon-gamma
- Intracellular Signaling Peptides and Proteins
- Lipopolysaccharides
- Macrophage Activation
- Macrophages, Peritoneal
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Necrosis
- Neutrophils
- Phenotype
Keywords
- Aging
- Chemokines
- Inflammation
- M1 macrophages
- Secondary necrosis
Lifespan and the proportion of older people in the population are increasing, with far reaching consequences for the social, political and economic landscape. Unless accompanied by an increase in health span, increases in age-related diseases will increase the burden on health care resources. Intervention studies to enhance healthy ageing need appropriate outcome measures, such as blood-borne biomarkers, which are easily obtainable, cost-effective, and widely accepted. To date there have been no systematic reviews of blood-borne biomarkers of mortality. To conduct a systematic review to identify available blood-borne biomarkers of mortality that can be used to predict healthy ageing post-retirement. Four databases (Medline, Embase, Scopus, Web of Science) were searched. We included prospective cohort studies with a minimum of two years follow up and data available for participants with a mean age of 50 to 75 years at baseline. From a total of 11,555 studies identified in initial searches, 23 fulfilled the inclusion criteria. Fifty-one blood borne biomarkers potentially predictive of mortality risk were identified. In total, 20 biomarkers were associated with mortality risk. Meta-analyses of mortality risk showed significant associations with C-reactive protein (Hazard ratios for all-cause mortality 1.42, p<0.001; Cancer-mortality 1.62, p<0.009; CVD-mortality 1.31, p = 0.033), N Terminal-pro brain natriuretic peptide (Hazard ratios for all-cause mortality 1.43, p<0.001; CHD-mortality 1.58, p<0.001; CVD-mortality 1.67, p<0.001) and white blood cell count (Hazard ratios for all-cause mortality 1.36, p = 0.001). There was also evidence that brain natriuretic peptide, cholesterol fractions, erythrocyte sedimentation rate, fibrinogen, granulocytes, homocysteine, intercellular adhesion molecule-1, neutrophils, osteoprotegerin, procollagen type III aminoterminal peptide, serum uric acid, soluble urokinase plasminogen activator receptor, tissue inhibitor of metalloproteinases 1 and tumour necrosis factor receptor II may predict mortality risk. There was equivocal evidence for the utility of 14 biomarkers and no association with mortality risk for CD40 ligand, cortisol, dehydroepiandrosterone, ferritin, haemoglobin, interleukin-12, monocyte chemoattractant protein 1, matrix metalloproteinase 9, myelopereoxidase, P-selectin, receptor activator of nuclear factor KappaB ligand, sex hormone binding globulin, testosterone, transferrin, and thyroid stimulating hormone and thyroxine. Twenty biomarkers should be prioritised as potential predictors of mortality in future studies. More studies using standardised protocols and reporting methods, and which focus on mortality rather than risk of disease or health status as an outcome, are needed.
MeSH Terms
- Aged
- Biomarkers
- Cardiovascular Diseases
- Cohort Studies
- Female
- Humans
- Longevity
- MEDLINE
- Male
- Middle Aged
- Neoplasms
The physical and immunological properties of the human intestinal epithelial barrier in aging are largely unknown. Ileal biopsies from young (7-12 years), adult (20-40 years) and aging (67-77 years) individuals not showing symptoms of gastrointestinal (GI) pathologies were used to assess levels of inflammatory cytokines, barrier integrity and cytokine production in response to microbial challenges. Increased expression of interleukin (IL)-6, but not interferon (IFN)γ, tumour necrosis factor (TNF)-α and IL-1β was observed during aging; further analysis showed that cluster of differentiation (CD)11c( ) dendritic cells (DCs) are one of the major sources of IL-6 in the aging gut and expressed higher levels of CD40. Up-regulated production of IL-6 was accompanied by increased expression of claudin-2 leading to reduced transepithelial electric resistance (TEER); TEER could be restored in in vitro and ex vivo cultures by neutralizing anti-IL-6 antibody. In contrast, expression of zonula occludens-1 (ZO-1), occludin and junctional-adhesion molecule-A1 did not vary with age and overall permeability to macromolecules was not affected. Finally, cytokine production in response to different microbial stimuli was assessed in a polarized in vitro organ culture (IVOC). IL-8 production in response to flagellin declined progressively with age although the expression and distribution of toll-like receptor (TLR)-5 on intestinal epithelial cells (IECs) remained unchanged. Also, flagellin-induced production of IL-6 was less pronounced in aging individuals. In contrast, TNF-α production in response to probiotics (VSL#3) did not decline with age; however, in our experimental model probiotics did not down-regulate the production of IL-6 and expression of claudin-2. These data suggested that aging affects properties of the intestinal barrier likely to impact on age-associated disturbances, both locally and systemically.
MeSH Terms
- Adult
- Age Factors
- Aged
- Biopsy
- Caco-2 Cells
- Child
- Culture Media, Conditioned
- Cytokines
- Dendritic Cells
- Electric Impedance
- Endoscopy
- Epithelium
- Gene Expression Profiling
- Gene Expression Regulation
- Humans
- Ileum
- Immunity, Innate
- Organ Culture Techniques
- Young Adult
Keywords
- aging
- infection
- innate immunity
- interleukin 6
- intestinal permeability
- intestine
Polyunsaturated fatty acid (PUFA) intake has increased over the last 100 yr, contributing to the current obesogenic environment. Obesity and aging are prominent risk factors for myocardial infarction (MI). How obesity interacts with aging to alter the post-MI response, however, is unclear. We tested the hypothesis that obesity in aging mice would impair the resolution of post-MI inflammation. PUFA diet (PUFA aging group) feeding to 12-mo-old C57BL/6J mice for 5 mo showed higher fat mass compared with standard lab chow (LC)-fed young (LC young group; 3-5 mo old) or aging alone control mice (LC aging group). LC young, LC aging, and PUFA aging mice were subjected to coronary artery ligation to induce MI. Despite similar infarct areas post-MI, plasma proteomic profiling revealed higher VCAM-1 in the PUFA aging group compared with LC young and LC aging groups, leading to increased neutrophil infiltration in the PUFA aging group (P<0.05). Macrophage inflammatory protein-1γ and CD40 were also increased at day 1, and myeloperoxidase remained elevated at day 5, an observation consistent with delayed wound healing in the PUFA aging group. Lipidomic analysis showed higher levels of arachidonic acid and 12(S)-hydroxyeicosatetraenoic acid at day 1 post-MI in the PUFA aging group compared with the LC aging group (all P<0.05), thereby mediating neutrophil extravasation in the PUFA aging group. The inflammation-resolving enzymes 5-lipoxygenase, cyclooxygenase-2, and heme oxyegnase-1 were altered to delay wound healing post-MI in the PUFA aging group compared with LC young and LC aging groups. PUFA aging magnifies the post-MI inflammatory response and impairs the healing response by stimulating prolonged neutrophil trafficking and proinflammatory lipid mediators.
MeSH Terms
- 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid
- Aging
- Animals
- Arachidonic Acid
- CD40 Antigens
- Cyclooxygenase 2
- Diet, High-Fat
- Fatty Acids, Omega-3
- Heme Oxygenase-1
- Inflammation
- Lipoxygenase
- Macrophage Inflammatory Proteins
- Mice
- Mice, Inbred C57BL
- Myocardial Infarction
- Neutrophil Infiltration
- Obesity
- Ventricular Function
- Wound Healing
Keywords
- inflammation
- lipid mediators
- lipidomics
- neutrophils
- polyunsaturated fatty acids
- proteomics
Newborns and young infants are particularly susceptible to infections, including Mycobacterium tuberculosis. Further, immunogenicity of vaccines against tuberculosis and other infectious diseases appears suboptimal early in life compared with later in life. We hypothesized that developmental changes in innate immunity would underlie these observations. To determine the evolution of innate responses to mycobacteria early in life, whole blood or PBMC from newborns, as well as 10- and 36-wk-old infants, was incubated with viable Mycobacterium bovis bacillus Calmette-Guérin or TLR ligands. Innate cell expression of cytokines and maturation markers was assessed, as well as activation of the proinflammatory NF-κB- and MAPK-signaling pathways. Bacillus Calmette-Guérin-induced production of the proinflammatory cytokines TNF-α, IL-6, and IL-12p40 increased from the newborn period to 9 mo of age in monocytes but not in myeloid dendritic cells. No changes in production of anti-inflammatory IL-10 were observed. CD40 expression increased with age in both cell populations. Older infants displayed substantial activation of all three signal transduction molecules: degradation of NF-κB inhibitor IκBα and phosphorylation of MAPK Erk and p38 upon TLR1/2 triggering, compared with predominant activation of only one of any of these molecules in newborns. Maturation of innate proinflammatory responses during the first 9 mo of life may underlie more effective control of mycobacteria and other pathogens observed later in infancy and age-related differential induction of Th1 responses by vaccination.
MeSH Terms
- Adult
- Age Factors
- Aging
- CD40 Antigens
- Cytokines
- Female
- Humans
- Immunity, Innate
- Infant
- Infant, Newborn
- MAP Kinase Signaling System
- Male
- Monocytes
- Mycobacterium bovis
- NF-kappa B
- Toll-Like Receptor 1
- Toll-Like Receptor 2
The role of macrophages and their interactions with T cells during aging is not well understood. We determined if activating elderly-derived macrophages could rescue age-related and tumor-induced T cell dysfunction. Healthy elderly (18-24 months) Balb/c contained significantly more splenic IL-10-secreting M2-macrophages and myeloid-derived suppressor cells than young (6-8 weeks) mice. Exposure to syngeneic mesothelioma or lung carcinoma-conditioned media polarized peritoneal macrophages into suppressive M2-macrophages regardless of age. Tumor-exposed, elderly, but not young-derived, macrophages produced high levels of IL-4 and could not induce T cell IFN-γ production. We attempted to rescue tumor-exposed macrophages with LPS/IFN-γ (M1 stimulus) or IL-2/agonist anti-CD40 antibody. Tumor-exposed, M1-stimulated macrophages retained high CD40 expression, yet TNF-α and IFN-γ production were diminished relative to non-tumor-exposed, M1-stimulated controls. These macrophages induced young and elderly-derived T cell proliferation however, T cells did not secrete IFN-γ. In contrast, tumor-exposed, IL-2/CD40-stimulated macrophages rescued elderly-derived T cell IFN-γ production, suggesting that IL-2/CD40-activated macrophages could rescue T cell immunity in aging hosts.
MeSH Terms
- Aging
- Animals
- CD40 Antigens
- Cell Line, Tumor
- Cell Proliferation
- Flow Cytometry
- Immunity, Innate
- Immunotherapy
- Interleukin-2
- Lung Neoplasms
- Macrophages, Peritoneal
- Mesothelioma
- Mesothelioma, Malignant
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Neoplasms, Experimental
- T-Lymphocytes
Dendritic cells (DCs) are critical for the generation of T-cell responses. DC function may be modulated by probiotics, which confer health benefits in immunocompromised individuals, such as the elderly. This study investigated the effects of four probiotics, Bifidobacterium longum bv. infantis CCUG 52486, B. longum SP 07/3, Lactobacillus rhamnosus GG (L.GG) and L. casei Shirota (LcS), on DC function in an allogeneic mixed leucocyte reaction (MLR) model, using DCs and T-cells from young and older donors in different combinations. All four probiotics enhanced expression of CD40, CD80 and CCR7 on both young and older DCs, but enhanced cytokine production (TGF-β, TNF-α) by old DCs only. LcS induced IL-12 and IFNγ production by DC to a greater degree than other strains, while B. longum bv. infantis CCUG 52486 favoured IL-10 production. Stimulation of young T cells in an allogeneic MLR with DC was enhanced by probiotic pretreatment of old DCs, which demonstrated greater activation (CD25) than untreated controls. However, pretreatment of young or old DCs with LPS or probiotics failed to enhance the proliferation of T-cells derived from older donors. In conclusion, this study demonstrates that ageing increases the responsiveness of DCs to probiotics, but this is not sufficient to overcome the impact of immunosenescence in the MLR.
MeSH Terms
- Adult
- Aged
- Aging
- Antigen Presentation
- Antigens, CD
- Bifidobacterium
- Cell Differentiation
- Cell Proliferation
- Cells, Cultured
- Cytokines
- Dendritic Cells
- Humans
- Isoantigens
- Lactobacillus casei
- Lactobacillus rhamnosus
- Lymphocyte Activation
- Lymphocyte Culture Test, Mixed
- Male
- Probiotics
- Receptors, CCR7
- T-Lymphocytes
- Young Adult
Keywords
- Ageing
- Allogeneic mixed leucocyte reaction
- CFSE
- Cytokine
- DCs
- Dendritic cells
- L. casei Shirota
- LcS
- MLR
- PAMPs
- PRPs
- Probiotics
- carboxyfluorescein diacetate succinimidyl ester
- dendritic cells
- mixed leucocyte reaction
- pathogen recognition patterns
- pathogen-associated molecular patterns
It is well-established that almost all cellular components of innate and adaptive immunity undergo age-related remodelling. The findings on age-related changes in both human and mouse dendritic cells (DCs) are conflicting, whereas there are no data on the influence of aging on rat DCs. In an attempt to fill this gap, freshly isolated splenic DCs expressing CD103 (αOX-62 integrin), a DC specific marker recognized by MRC OX62 monoclonal antibody, from 3- (young) and 26-month-old (aged) Albino Oxford rats were examined for subset composition, expression of activation/differentiation markers (CD80, CD86 and CD40 and MHC II molecules) and endocytic capacity using flow cytometric analysis (FCA). In addition, splenic OX62 DCs cultured in the presence or absence of LPS were analysed for the activation marker and TNF-α, IL-6, IL-12, IL-23, TGF-β1, IL-10 expression using FCA, RT-PCR and ELISA, respectively. Moreover, the allostimulatory capacity of OX62 DCs and IFN-γ, IL-4 and IL-17 production by CD4 T cells in mixed leukocyte reaction was quantified using FCA and ELISA, respectively. It was found that aging: i) shifts the CD4 :CD4- subset ratio in the OX62 DCs population towards the CD4- subset and ii) influences DCs maturation (judging by activation marker expression and efficiency of endocytosis) by affecting the expression of intrinsic (TNF-α and IL-10) and extrinsic maturation regulators. Furthermore, in LPS-matured OX62 DCs from aged rats expression of TNF-α, IL-12, IL-23 and IL-6 was increased, whereas that of IL-10 was diminished compared with the corresponding cells from young rats. Moreover, in MLR, OX62 DCs from aged rats exhibited enhanced Th1/Th17 driving force and diminished allostimulatory capacity compared with those from young rats.
MeSH Terms
- Aging
- Animals
- Culture Media
- Cytokines
- Dendritic Cells
- Enzyme-Linked Immunosorbent Assay
- Flow Cytometry
- Rats
- Real-Time Polymerase Chain Reaction
- Spleen
- T-Lymphocytes, Helper-Inducer
Autoimmunity increases with aging indicative of reduced immune tolerance, but the mechanisms involved are poorly defined. In recent years, subsets of B cells with immunoregulatory properties have been identified in murine models of autoimmune disorders, and these cells downregulate immune responses via secretion of IL10. In humans, immature transitional B cells with a CD19( ) CD24(hi) CD38(hi) phenotype have been reported to regulate immune responses via IL10 production. We found the frequency and numbers of CD19( ) CD24(hi) CD38(hi) cells were reduced in the PBMC pool with age. IL10 expression and secretion following activation via either CD40, or Toll-like receptors was also impaired in CD19( ) CD24(hi) CD38(hi) B cells from healthy older donors. When investigating the mechanisms involved, we found that CD19( ) CD24(hi) CD38(hi) B-cell function was compromised by age-related effects on both T cells and B cells: specifically, CD40 ligand expression was lower in CD4 T cells from older donors following CD3 stimulation, and signalling through CD40 was impaired in CD19( ) CD24(hi) CD38(hi) B cells from elders as evidenced by reduced phosphorylation (Y705) and activation of STAT3. However, there was no age-associated change in expression of costimulatory molecules CD80 and CD86 on CD19( ) CD24(hi) CD38(hi) cells, suggesting IL10-dependent immune suppression is impaired, but contact-dependent suppressive capacity is intact with age. Finally, we found a negative correlation between CD19( ) CD24(hi) CD38(hi) B-cell IL10 production and autoantibody (Rheumatoid factor) levels in older adults. We therefore propose that an age-related decline in CD19( ) CD24(hi) CD38(hi) B cell number and function may contribute towards the increased autoimmunity and reduced immune tolerance seen with aging.
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Aging
- Antigens, CD
- Autoimmunity
- B-Lymphocytes
- Cell Differentiation
- Female
- Humans
- Male
- Middle Aged
- Signal Transduction
- Young Adult
Keywords
- B cells
- autoimmunity
- cellular immunology
- inflammation
- rheumatoid factor
Changes to innate cells, such as macrophages and myeloid-derived suppressor cells (MDSCs), during aging in healthy or tumor-bearing hosts are not well understood. We compared macrophage subpopulations and MDSCs from healthy young (6-8 weeks) C57BL/6J mice to those from healthy geriatric (24-28 months) mice. Spleens, lymph nodes, and bone marrow of geriatric hosts contained significantly more M2 macrophages and MDSCs than their younger counterparts. Peritoneal macrophages from geriatric, but not young, mice co-expressed CD40 and CX3CR1 that are usually mutually exclusively expressed by M1 or M2 macrophages. Nonetheless, macrophages from geriatric mice responded to M1 or M2 stimuli similarly to macrophages from young mice, although they secreted higher levels of TGF-β in response to IL-4. We mimicked conditions that may occur within tumors by exposing macrophages from young vs. geriatric mice to mesothelioma or lung carcinoma tumor cell-derived supernatants. While both supernatants skewed macrophages toward the M2-phenotype regardless of age, only geriatric-derived macrophages produced IL-4, suggesting a more immunosuppressive tumor microenvironment will be established in the elderly. Both geriatric- and young-derived macrophages induced allogeneic T-cell proliferation, regardless of the stimuli used, including tumor supernatant. However, only macrophages from young mice induced T-cell IFN-γ production. We examined the potential of an IL-2/agonist anti-CD40 antibody immunotherapy that eradicates large tumors in young hosts to activate macrophages from geriatric mice. IL-2-/CD40-activated macrophages rescued T-cell production of IFN-γ in geriatric mice. Therefore, targeting macrophages with IL-2/anti-CD40 antibody may improve innate and T-cell immunity in aging hosts.
MeSH Terms
- Aging
- Animals
- CD4-Positive T-Lymphocytes
- CD40 Antigens
- CD8-Positive T-Lymphocytes
- CX3C Chemokine Receptor 1
- Cell Line, Tumor
- Cell Proliferation
- Cellular Senescence
- Culture Media, Conditioned
- Immunity, Innate
- Interferon-gamma
- Interleukin-2
- Interleukin-4
- Lung Neoplasms
- Lymphocyte Activation
- Macrophages
- Mesothelioma
- Mice
- Mice, Inbred C57BL
- Receptors, Chemokine
- Transforming Growth Factor beta
- Tumor Microenvironment
The intricate interactions between the immune, endocrine and central nervous systems shape the innate immune response of the brain. We have previously shown that estradiol suppresses expression of immune genes in the frontal cortex of middle-aged ovariectomized rats, but not in young ones reflecting elevated expression of these genes in middle-aged, ovarian hormone deficient animals. Here, we explored the impact of menopause on the microglia phenotype capitalizing on the differential expression of macrophage-associated genes in quiescent and activated microglia. We selected twenty-three genes encoding phagocytic and recognition receptors expressed primarily in microglia, and eleven proinflammatory genes and followed their expression in the rat frontal cortex by real-time PCR. We used young, middle-aged and middle-aged ovariectomized rats to reveal age- and ovariectomy-related alterations. We analyzed the expression of the same set of genes in the postcentral and superior frontal gyrus of pre- and postmenopausal women using raw microarray data from our previous study. Ovariectomy caused up-regulation of four classic microglia reactivity marker genes including Cd11b, Cd18, Cd45 and Cd86. The change was reversible since estradiol attenuated transcriptional activation of the four marker genes. Expression of genes encoding phagocytic and toll-like receptors such as Cd11b, Cd18, C3, Cd32, Msr2 and Tlr4 increased, whereas scavenger receptor Cd36 decreased following ovariectomy. Ovarian hormone deprivation altered the expression of major components of estrogen and neuronal inhibitory signaling which are involved in the control of microglia reactivity. Strikingly similar changes took place in the postcentral and superior frontal gyrus of postmenopausal women. Based on the overlapping results of rat and human studies we propose that the microglia phenotype shifts from the resting toward the reactive state which can be characterized by up-regulation of CD11b, CD14, CD18, CD45, CD74, CD86, TLR4, down-regulation of CD36 and unchanged CD40 expression. As a result of this shift, microglial cells have lower threshold for subsequent activation in the forebrain of postmenopausal women.
MeSH Terms
- Adult
- Age Factors
- Aged
- Aging
- Animals
- Antigens, CD
- Cytokines
- Estradiol
- Estrogen Receptor alpha
- Female
- Frontal Lobe
- Gene Expression Regulation
- Histocompatibility Antigens
- Humans
- Menopause
- Middle Aged
- Ovariectomy
- Phagocytosis
- RNA, Messenger
- Rats
- Rats, Wistar
- Toll-Like Receptor 4
- Toll-Like Receptor 9
Fully competent oocytes represent the final outcome of a highly selective process. The decline of oocyte competence with ageing, coupled to quantitative decrease of ovarian follicles has been well established; on the contrary, its molecular bases are still poorly understood. Through quantitative high throughput PCR, we investigated the role of apoptotic machinery (AM) in this process. To this aim, we determined AM transcriptome in mature MII oocyte pools from women aged more than 38 years (cohort A), and compared to women aged up to 35 years (cohort B). Subsequently, 10 representative AM genes were selected and analyzed in 33 single oocytes (15 from cohort A and 18 from cohort B). These investigations led us to identify: (1) the significant upregulation of proapoptotic genes such us CD40, TNFRSF10A, TNFRSF21 and the downregulation of antiapoptotic genes such as BCL2 and CFLAR in cohort A respect to cohort B; (2) AM transcripts that have not previously been reported in human oocytes (BAG3, CD40, CFLAR, TNFRSF21, TRAF2, TRAF3). Our results demonstrated that during maturation the oocytes from older women selectively accumulate mRNAs that are able to trigger the extrinsic apoptotic pathway. These data contribute to clarify the molecular mechanisms of AM involvement in the natural selection strategy of removing low quality oocytes and preventing unfit or poorly fit embryos.
MeSH Terms
- Adaptor Proteins, Signal Transducing
- Adult
- Aging
- Apoptosis
- Apoptosis Regulatory Proteins
- CASP8 and FADD-Like Apoptosis Regulating Protein
- CD40 Antigens
- Down-Regulation
- Female
- Humans
- Maternal Age
- Oocytes
- Proto-Oncogene Proteins c-bcl-2
- Receptors, TNF-Related Apoptosis-Inducing Ligand
- Receptors, Tumor Necrosis Factor
- Transcriptome
- Up-Regulation
Advancing age leads to significant decline in immune functions. IL-21 is produced primarily by T follicular helper (Tfh) cells and is required for effective immune cell functions. Here we compared the induction of IL-21 in aged and young subjects. Our investigation demonstrates that CD4 T cells from healthy elderly individuals (age ≥ 65) secreted significantly higher levels of IL-21 on priming with aged and young dendritic cells (DC). Though the aged and young DCs secreted comparable levels of IL-12 on stimulation with anti-CD40 antibody and LPS, culture of DCs with aged CD4 T cells resulted in increased production of IL-21 as compared to that with young CD4 T cells. Further examination revealed that the response of aged naïve CD4 T cells to IL-12 was altered, resulting in increased differentiation of aged Th cells towards Tfh cells. Investigation into the signaling mechanism suggested that phosphorylation of STAT-4 in response to IL-12 was sustained for a longer duration in aged CD4 T cells as compared to CD4 T cells from young subjects. Additional analysis demonstrated that increased IL-21 secretion correlated with chronic CMV infection in aged subjects. These findings indicate that chronic CMV infection alters the response of aged CD4 T cells to IL-12 resulting in an increased secretion of IL-21 and that aging affects Tfh cell responses in humans which may contribute to age-associated inflammation and immune dysfunctions.
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Aging
- CD4-Positive T-Lymphocytes
- Cell Differentiation
- Cells, Cultured
- Coculture Techniques
- Cytomegalovirus Infections
- Dendritic Cells
- Enzyme Activation
- Enzyme-Linked Immunosorbent Assay
- Female
- Humans
- Interleukins
- Lymphocyte Activation
- Male
- STAT4 Transcription Factor
- Young Adult
The immune system changes with age. In this study we characterized immune changes by performing immunologic screening profiles on ageing individuals. This study was performed at Akdeniz University, in the Faculty of Medicine, Department of Immunology. Healthy volunteers consisted of a younger group (22 donors) and an older group (45 individuals). All subjects had no serious health problems (i.e. chronic heart, lung, liver or immunological diseases) and were taking no prescribed medications. Flow cytometry analysis was used to evaluate CD3, CD4, CD8, CD16, CD19, CD28, CD40, CD45, CD56, CD80, CD86, CTLA-4 and ELISA for IL-1 beta, IL-2, IL-6, IL-10, IFN-gamma, TNF-alpha expression In addition, NK activity and induced cytokine expression (by bioassay and ELISA, respectively) were evaluated. No statistical differences were observed between the two groups in expression of CD3, CD8, CD19, CD80, CD86, CD16, CD 56, or CD28. A higher frequency of expression of CD4, CTLA-4, CD40, and CD45 was seen in older subjects by comparison with younger subjects. Cytokine profiles expressed by stimulated monocytes and lymphocytes from the two groups showed no difference in IL-1 beta, IL-2, IL-6, IL-10, TNF-alpha, and IFN-gamma production levels. We found increased expression levels of CD40 and CD45 levels in healthy older (age: 59.42 /- 5.89) versus younger individuals (age: 30.32 /- 2.29). CTLA-4 expression levels were also higher in older subjects, with no difference in CD28 expression levels between younger/older individuals.
MeSH Terms
- Adult
- Age Factors
- Aging
- Biomarkers
- CD40 Antigens
- CTLA-4 Antigen
- Cytokines
- Female
- Flow Cytometry
- Humans
- Immunity, Humoral
- Leukocyte Common Antigens
- Lymphocytes
- Male
- Middle Aged
- Monocytes
Many autoimmune diseases are characterised by a female predominance. This may be caused by sex hormones, sex chromosomes or both. This report uses a transgenic mouse model to investigate how sex chromosome complement, not confounded by differences in gonadal type, might contribute to lupus pathogenesis. Transgenic NZM2328 mice were created by deletion of the Sry gene from the Y chromosome, thereby separating genetic from gonadal sex. Survival, renal histopathology and markers of immune activation were compared in mice carrying the XX versus the XY(-) sex chromosome complement, with each genotype being ovary bearing. Mice with XX sex chromosome complement compared with XY(-) exhibited poorer survival rates and increased kidney pathology. Splenic T lymphocytes from XX mice demonstrated upregulated X-linked CD40 ligand expression and higher levels of activation markers ex vivo. Increased MMP, TGF and IL-13 production was found, while IL-2 was lower in XX mice. An accumulation of splenic follicular B cells and peritoneal marginal zone B cells was observed, coupled with upregulated costimulatory marker expression on B cells in XX mice. These data show that the XX sex chromosome complement, compared with XY(-), is associated with accelerated spontaneous lupus.
MeSH Terms
- Animals
- Biomarkers
- CD28 Antigens
- CD3 Complex
- CD40 Ligand
- Chromosome Duplication
- Female
- Kidney
- Kidney Diseases
- Longevity
- Lupus Erythematosus, Systemic
- Male
- Mice
- Mice, Transgenic
- Sex Chromosome Aberrations
- Sex Chromosome Disorders
- Spleen
- T-Lymphocytes
- Up-Regulation
- X Chromosome
- Y Chromosome
T cell-dependent B-cell responses decline with age, suggesting defective CD4 T-cell function. CD4 memory T cells from individuals older than 65 y displayed increased and sustained transcription of the dual-specific phosphatase 4 (DUSP4) that shortened expression of CD40-ligand (CD40L) and inducible T-cell costimulator (ICOS) (both P < 0.001) and decreased production of IL-4, IL-17A, and IL-21 (all P < 0.001) after in vitro activation. In vivo after influenza vaccination, activated CD4 T cells from elderly individuals had increased DUSP4 transcription (P = 0.002), which inversely correlated with the expression of CD40L (r = 0.65, P = 0.002), ICOS (r = 0.57, P = 0.008), and IL-4 (r = 0.66, P = 0.001). In CD4 KO mice reconstituted with DUSP4 OT-II T cells, DUSP4 had a negative effect on the expansion of antigen-specific B cells (P = 0.003) and the production of ova-specific antibodies (P = 0.03) after immunization. Silencing of DUSP4 in memory CD4 T cells improved CD40L (P < 0.001), IL-4 (P = 0.007), and IL-21 (P = 0.04) expression significantly more in the elderly than young adults. Consequently, the ability of CD4 memory T cells to support B-cell differentiation that was impaired in the elderly (P = 0.004) was restored. Our data suggest that increased DUSP4 expression in activated T cells in the elderly in part accounts for defective adaptive immune responses.
MeSH Terms
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- Aging
- Animals
- B-Lymphocytes
- Biomarkers
- CD4-Positive T-Lymphocytes
- Dual-Specificity Phosphatases
- Gene Silencing
- Humans
- Immunity, Humoral
- Immunologic Memory
- Influenza, Human
- Lymphocyte Activation
- Mice
- Mitogen-Activated Protein Kinase Phosphatases
- Protein Tyrosine Phosphatases
- Signal Transduction
- T-Lymphocytes, Helper-Inducer
- Vaccination
- Young Adult
This paper is to analyze the changes of important membrane type molecules of the spleen B cells and their significance on the basis of biology identification by establishing subacute aging mice model with D-galactose. Health Kunming mice are injected with 100 ng/L D-galactose, 0.25 mL/20 g, once per day, for 42 days consecutively, into their back necks. The animals' living conditions and biological behaviors are observed everyday and the dynamic changes of their weight are measured regularly. The biology identification of aging model mice is conducted by means of measuring the SOD viability and malondialdehyde (MDA) concentration in serum; the analysis of the activation- and memory-related important membrane type molecules of spleen cells is carried out with immune fluorescence and flow cytometry; the analysis of the concentration of IL-4 in serum is conducted by ELISA. Building a successful subactue aging mice model.The results of immune fluorescence and flow cytometry showed that CD20( ); was 56.8%, CD40( ); was 43.6%, CD20( );CD45RA( );B was 14.04%, CD40( );CD45RA( );B was 35.4%, CD20( );CD86( );B was 2.25%, CD40( );CD86( );B was 4.38%, CD20( );CD196( );B was 10.68%, and CD40( );CD196( );B was 10.98%. The results of ELISA showed that the average level of IL-4 in serum was 7.93 ng/L. The statistical analysis showed that the expressions of CD20, CD40, CD45RA, and CD86 of the spleen cells of the model control group and the average level of IL-4 in serum were lower than the normal control group(P<0.05)while CD196 was higher than the normal control group(P<0.01). In the body's aging process, the expressions of the activation- and memory-related important membrane type molecules of spleen cells change, activated cells reduce, memory cells increase, and the expression of IL-4 in serum drop, resulting in the immune system function disorder.
MeSH Terms
- Aging
- Animals
- B-Lymphocytes
- Galactose
- Immunologic Memory
- Interleukin-4
- Lymphocyte Activation
- Malondialdehyde
- Mice
- Spleen
- Superoxide Dismutase
Aging has profound effects on the immune system, including thymic involution, reduced diversity of the T cell receptor repertoire, reduced effector T cell and B cell function and chronic increase of proinflammatory cytokine production by innate immune cells. The precise effects of aging on conventional dendritic cells (cDC), the main antigen presenting cells of the immune system, however, are not well understood. We found that in aged mice the number of cDC in the spleen and lymph nodes remained stable, whereas the number of cDC in the lungs increased with age. Whereas cDC in mice showed similar cycling kinetics in all organs tested, cDC reconstitution by aged bone marrow precursors was relatively higher than that of their young counterparts. With the exception of CD86, young and aged cDC did not differ in their expression of co-stimulatory molecules at steady state. Most toll-like receptor (TLR) ligands induced comparable upregulation of co-stimulatory molecules CD40, CD86 and B7H1 on young and aged cDC, whereas TLR2 and TLR5 stimulation resulted in reduced upregulation of CD80 and CD86 on aged cDC in vitro. In vivo, influenza infection-induced upregulation of CD86, but not other co-stimulatory molecules, was lower in aged DC. Young and aged DC were equally capable of direct and cross presentation of antigens in vitro. Transcriptome analysis did not reveal any significant difference between young and aged cDC. These data show that unlike T and B cells, the maintenance of cDC throughout the life of a healthy animal is relatively robust during the aging process.
MeSH Terms
- Aging
- Animals
- Antigen Presentation
- B7-2 Antigen
- B7-H1 Antigen
- Bone Marrow Cells
- CD40 Antigens
- Cell Count
- Dendritic Cells
- Female
- Flow Cytometry
- Immunophenotyping
- Influenza A virus
- Lipopeptides
- Lipopolysaccharides
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Oligonucleotide Array Sequence Analysis
- Orthomyxoviridae Infections
- Spleen
- Toll-Like Receptors
- Transcriptome
- Up-Regulation
The glycoprotein, CD200, is primarily expressed on neurons and its cognate receptor CD200R is expressed principally on cells of the myeloid lineage, including microglia. The interaction of CD200 with its receptor plays a significant role in maintaining microglia in a quiescent state and therefore a decrease in CD200 expression in brain is associated with evidence of microglial activation. Conversely, activation of CD200R, for example using a CD200 fusion protein (CD200Fc), should result in a decrease in microglial activation. Here we assessed the effect of delivery of CD200Fc intrahippocampally on microglial activation and on long-term potentiation (LTP) in perforant path-granule cell synapses in young and aged rats. We hypothesized that the age-related changes in microglial activation would be attenuated by CD200Fc resulting in an improved ability of aged rats to sustain LTP. The data indicate that expression of markers of microglial activation including major histocompatibility complex Class II (MHCII) and CD40 mRNA, as well as MHCII immunoreactivity, were increased in hippocampus of aged, compared with young, rats and that these changes were associated with a deficit in LTP; these changes were attenuated in hippocampal tissue prepared from aged rats which received CD200Fc. Microglial activation and a deficit in LTP have also been reported in lipopolysaccharide (LPS)-treated rats and, here, we report that these changes were also attenuated in CD200Fc-treated animals. Thus the negative impact of microglial activation on the ability of aged and LPS-treated rats to sustain LTP is ameliorated when CD200R is activated by CD200Fc.
MeSH Terms
- Actins
- Aging
- Animals
- Antigens, CD
- Blotting, Western
- Chemokines
- Cytokines
- Excitatory Postsynaptic Potentials
- Genes, MHC Class II
- Hippocampus
- Inflammation
- Lipopolysaccharides
- Long-Term Potentiation
- Macrophage Activation
- Male
- Membrane Proteins
- Microglia
- Microinjections
- Neuronal Plasticity
- Rats
- Rats, Wistar
- Real-Time Polymerase Chain Reaction
- Recombinant Fusion Proteins
- Synaptophysin
Lipid metabolites and cytokines, including chemokines and growth factors, are the key regulators of immune cell function and differentiation, and thus, dysregulation of these regulators is associated with various human diseases. However, previous studies demonstrating a positive correlation of cytokine levels with aging may have been influenced by various environmental factors and underlying diseases. Also, data regarding cytokine profiling in the elderly are limited to a small subset of cytokines. We compared the profiles of 22 cytokines, including chemokines and growth factors, in a case-controlled study group of a gender-matched, healthy cohort of 55 patients over the age of 65 and 55 patients under the age of 45. Assessment of serum cytokine concentrations was performed using commercially-available multiplex bead-based sandwich immunoassays. Soluble CD40 ligand (sCD40L) and transforming growth factor alpha (TGF-α) levels were significantly higher in the elderly patients, whereas granulocyte colony-stimulating factor (G-CSF), granulocyte-monocyte colony-stimulating factor (GM-CSF), and monocyte chemoattractant protein-1 (MCP-1) levels were significantly lower in the elderly patients. The partial correlation analysis demonstrating the correlation between cytokine levels when controlled for gender, systolic blood pressure, total cholesterol, HDL cholesterol, triglyceride, and serum creatinine levels further demonstrated that G-CSF, GM-CSF, and MCP-1 had significant negative correlations with age, whereas sCD40L and TGF-α had significant positive correlations. Future studies will focus on examining the significance of these age-related changes in circulating cytokines and other biological markers and their potential contribution to the development of different age-associated diseases.
MeSH Terms
- Adult
- Aged
- Aging
- Biomarkers
- Blood Glucose
- Blood Pressure
- Body Mass Index
- Chemokines
- Cholesterol
- Creatinine
- Cytokines
- Female
- Health
- Humans
- Immunoassay
- Intercellular Signaling Peptides and Proteins
- Male
- Microspheres
- Smoking
- Triglycerides
We have discovered a distinct mature B-cell subset that accumulates with age, which we have termed age-associated B cells. These cells comprise up to 30% of mature B cells by 22 months. Despite sharing some features with other mature B-cell subsets, they are refractory to BCR and CD40 stimulation. Instead, they respond to TLR9 or TLR7 stimulation and divide maximally on combined BCR and TLR ligation, leading to Ig production and preferential secretion of IL-10 and IL-4. Although similar to follicular B cells in both B-lymphocyte stimulator (BLyS) receptor expression and BLyS binding capacity, these cells do not rely on BLyS for survival. They are neither cycling nor the result of intrinsically altered B lymphopoiesis in aged BM, but instead appear to be generated from mature B cells that exhaustively expand during the individual's lifetime. Finally, they present Ag effectively and favor polarization to a TH17 profile. Together, these findings reveal that while the magnitude of the mature primary B-cell niche is maintained with age, it is increasingly occupied by cells refractory to BCR-driven activation yet responsive to innate receptor stimulation.
MeSH Terms
- Aging
- Animals
- B-Cell Activating Factor
- B-Lymphocyte Subsets
- Cell Proliferation
- Cells, Cultured
- Female
- Immunity, Innate
- Lymphocyte Activation
- Lymphocyte Count
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mice, Transgenic
CD4 T cells regulate humoral and cell-mediated immune responses, which are progressively impaired in aging, resulting in susceptibility to infections and cancer. Dendritic cells (DCs) are major activators of T cells, providing signals that drive their expansion and differentiation. In this study, we asked if decreased CD4 T cell responses were influenced by the age of DCs rather than being exclusively due to T cell defects. Old T cells transferred to young recipients expanded and differentiated similarly to young T cells. However, aged recipients were poor stimulators of both old and young T cells, which failed to acquire CD44 expression and produce interferon gamma (IFN-γ). DCs in aged hosts expressed fewer MHC-peptide complexes. The CD86 expression in the DCs of both hosts was similar; however, CD40 levels were reduced in old DCs. Finally, old DCs failed to produce inflammatory cytokines in response to LPS. Our results indicate that the impairment of aged CD4 T cell function is intimately related to multiple alterations in aged DCs, rather than being caused solely by intrinsic T cell defects, suggesting that the function of aged T cells may be partially rescued in vivo when appropriate stimulation is applied. These findings are relevant to vaccination design for elderly populations.
MeSH Terms
- Age Factors
- Aging
- Animals
- Antigen Presentation
- CD4-Positive T-Lymphocytes
- CD40 Antigens
- Cell Differentiation
- Cytokines
- Dendritic Cells
- Hyaluronan Receptors
- Interferon-gamma
- Lipopolysaccharides
- Major Histocompatibility Complex
- Mice
- Mice, Inbred C57BL
- Peptides
Epidemiological studies have shown that low vitamin D status results in impaired immune function and is associated with the prevalence of autoimmune and inflammatory conditions. Vitamin D supplementation has been shown to reduce circulating concentrations of inflammatory markers in such conditions. However, the possible beneficial effect of vitamin D supplementation in the general population, particularly for those individuals living at high latitudes where hypovitaminosis D is common during wintertime, remains unclear. The aim of this study was to assess the effect of vitamin D supplementation using doses of 5, 10, and 15 μg/d cholecalciferol (D3) compared with placebo on cytokine concentrations throughout winter in apparently healthy younger (aged 20-40 y) and older (aged ≥64 y) adults. A total of 211 younger and 202 older adults completed the 22-wk intervention (from October to March) with >85% compliance. Serum concentrations of 25-hydroxycholecalciferol [25(OH)D3], high sensitivity C-reactive protein, IL-6, IL-10, soluble CD40 ligand, TGFβ, TNFα, and fibrinogen were measured using ELISA. 25(OH)D3 concentrations significantly decreased in the placebo and 5 and 10/d μg D3 groups in the younger cohort and in the placebo group in the older cohort. Whereas 15 μg/d D3 supplementation maintained 25(OH)D3 concentrations in the younger cohort (baseline, 75.9 nmol/L; postintervention, 69.0 nmol/L) and significantly increased concentrations in the older cohort (baseline, 55.1 nmol/L; postintervention, 73.9 nmol/L), it had no significant effect on cytokine concentrations (ANCOVA, P > 0.05). The long-term effects of low vitamin D status remain to be elucidated and optimization of vitamin D status in otherwise healthy individuals may potentially have lasting beneficial effects on the immune system.
MeSH Terms
- Acute-Phase Proteins
- Adult
- Aged
- Aged, 80 and over
- Aging
- Biomarkers
- Calcifediol
- Cholecalciferol
- Cohort Studies
- Cytokines
- Dietary Supplements
- Dose-Response Relationship, Drug
- Double-Blind Method
- Female
- Humans
- Male
- Medication Adherence
- Middle Aged
- Nutritional Status
- Seasons
- Vitamin D Deficiency
- Young Adult
Nose-associated lymphoid tissue (NALT) in the rodent upper respiratory tract develops postnatally and is considered to be independent of several factors known to be involved in the organogenesis of LN and Peyer's patches (PP). In this study we demonstrate that at least two different pathways result in NALT development. Following NALT anlage formation the intrinsic pathway relies on a signaling cascade including those mediated through the chemokine receptor CXCR5 and the lymphotoxin beta receptor (LTbetaR). This allows for the formation of high endothelial venules and thereby the recruitment of lymphocytes into NALT. Alternatively, high endothelial venule formation and lymphocyte recruitment can be induced in the NALT anlage by environmental signals, which are independent of LT-betaR and chemokine receptor CXCR5 signaling but in part rely on CD40 ligand. Thus, our study identifies a novel mechanism that facilitates the rescue of NALT development at late stages in adult life independent of the canonical LTbetaR-CXCR5 signaling axis.
MeSH Terms
- Adoptive Transfer
- Aging
- Animals
- Antibodies, Monoclonal
- Antigens
- Antigens, Surface
- B-Lymphocytes
- CD40 Ligand
- Cell Adhesion Molecules
- Cell Count
- Cell Movement
- Germ-Free Life
- Lymph Nodes
- Lymphocyte Activation
- Lymphocytes
- Lymphoid Tissue
- Lymphotoxin beta Receptor
- Lymphotoxin-alpha
- Membrane Proteins
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Mutant Strains
- Mucoproteins
- Nasal Mucosa
- Propionibacterium acnes
- Receptors, CXCR5
- Signal Transduction
- Spleen
- Tumor Necrosis Factor Ligand Superfamily Member 14
- Venules
The T cell branch of the immune system has been extensively studied in the elderly and it is known that the elderly have impaired immune function, mainly due to the chronic antigenic load that ultimately causes shrinkage of the T cell repertoire and filling of the immunologic space with memory T cells. In the present paper, we describe the IgD(-)CD27(-) double-negative B cell population which (as we have recently described) is higher in the elderly. Most of these cells were IgG( ). Evaluation of the telomere length and expression of the ABCB1 transporter and anti-apoptotic molecule, Bcl2, shows that they have the markers of memory B cells. We also show that these cells do not act as antigen presenting cells, as indicated by the low levels of CD80 and DR, nor do they express significant levels of the CD40 molecule necessary to interact with T lymphocytes through the ligand, CD154. Hence, we hypothesize that these expanded cells are late memory or exhausted cells that have down-modulated the expression of CD27 and filled the immunologic space in the elderly. These cells might be the age-related manifestation of time-enduring stimulation or dysregulation of the immune system.
MeSH Terms
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1
- Adult
- Age Factors
- Aged
- Aged, 80 and over
- Aging
- Antigens, CD19
- B-Lymphocyte Subsets
- B7-1 Antigen
- CD40 Antigens
- Cells, Cultured
- Flow Cytometry
- HLA-DR Antigens
- Humans
- Immunoglobulin D
- Immunologic Memory
- Ki-67 Antigen
- Middle Aged
- Proto-Oncogene Proteins c-bcl-2
- Telomere
- Tumor Necrosis Factor Receptor Superfamily, Member 7
- Young Adult
A common change that occurs with age in the central nervous system is an increase in microglial-associated inflammation. This is usually coupled with an increase in the concentration of the inflammatory cytokine interleukin-1beta (IL-1beta) in the hippocampus and an inhibition in long-term potentiation. To assess the effects of a novel preparation of phospholipid nanoparticles incorporating phosphatidylglycerol, VP025, on inflammatory changes in hippocampus of aged and lipopolysaccharide (LPS)-treated rats. We report that a possible initial target cell of the putative anti-inflammatory actions of VP025 may be macrophages, as VP025 is engulfed by, and has the capacity to alter the activity of, these cells. VP025 reversed the increase in IFN-gamma concentration in supernatant taken from peritoneal macrophages harvested from LPS-treated rats. In addition, markers of microglial activity, major histocompatibility complex class II (MHC II) mRNA expression, CD40 expression and IL-1beta concentration were increased, and CD200 expression was reduced, in the hippocampus of these rats. VP025 reversed changes in CD40, IL-1beta and CD200 in aged rats, and also restored long-term potentiation in aged and LPS-treated rats. We conclude that VP025 has the ability to modulate the activity of macrophage, microglia and neurons in response to stressors such as ageing and LPS treatment.
MeSH Terms
- Adult
- Aging
- Animals
- Anti-Inflammatory Agents
- Encephalitis
- Gliosis
- Hippocampus
- Humans
- Immunomodulation
- Interferon-gamma
- Interleukin-1beta
- Long-Term Potentiation
- Macrophages
- Male
- Memory Disorders
- Microglia
- Nanoparticles
- Perforant Pathway
- Phagocytosis
- Phosphatidylglycerols
- Phospholipids
- Rats
- Rats, Wistar
- Tumor Cells, Cultured
- Tumor Necrosis Factor-alpha
Multiple investigators have reported the presence of defects in the immune response of the elderly [Castle In: Clin Infect Dis 31:578, 2000; Ortqvist et al. In: Eur Respir J 30:414-422, 2007; Saurwein-Teissl et al. In: J Immunol 168:5893, 2002; Haynes et al. In: Proc Natl Acad Sci USA 100:15053-15058, 2003]. These defects reduce the magnitude of the immune response to infection and to vaccination. In individuals greater than 55 years of age, the probability of developing a fully protective neutralizing antibody response to the yearly multivalent particle inactivated influenza vaccine is less than 20% [Jefferson et al. In: Lancet 264:1165-1174, 2005; Goodwin et al. In: Vaccine 24:1159-1169, 2006; Jackson et al. In: Lancet 372:398-405, 2008; Simonsen and Taylor In: Lancet 7:658-666, 2007]. The defects in the aged immune system that are responsible for this limited response to vaccination in the older age groups include functional defects of the antigen presenting cells, functional defects in CD4 helper CD4 T cells and monocytes, and an altered microenvironment [Eaton et al. In: J Exp Med 200:1613-1622, 2004; Dong et al. In: J Gen Virol 84:1623-1628, 2003; Deng et al. In: Immunology 172:3437-3446, 2004; Cella et al. In: J Exp Med 184:747-752, 1996]. Starting at puberty, the involution of the thymus and the consequent reduction of the export of naïve T cells specific to neo-antigens leads to the reduction of the ratio of antigen naïve to memory cells as chronological age advances [Prelog In: Autoimmun Rev 5:136-139, 2006; McElhaney et al. In: J Immunology 176:6333-6339, 2006]. Changes in glycosylation of T cells and target antigens acquired during the aging process and the antibodies to these new glycopeptides and glycoproteins may also contribute to a reduction in the functioning of the adaptive immune response [Ishii et al. In: J Clin Neurosci 14:110-115, 2007; Shirai et al. In: Clin Exp Immunol 12:455-464, 1972; Adkins and Riley In: Mech Ageing Dev 103:147-164, 1998; Ben-Yehuda and Weksler In: Cancer Investigation 10:525-531, 1992]. One of the more interesting examples of the functional defects in the cells of the adaptive immune response is a reduced level of expression in the surface cytoadhesion and activation receptor molecules on CD4 helper T cells undergoing activation during vaccination. Upon infection or vaccination, CD40L is typically increased on the surface of CD4 helper T cells during activation, and this increased expression is absolutely essential to the CD40L promotion of expansion of antigen-specific B cells and CD 8 effector T cells in response to infection or vaccination [Singh et al. In: Protein Sci 7:1124-1135, 1998; Grewal and Flavell In: Immunol Res 16: 59-70, 1997; Kornbluth In: J Hematother Stem Cell Res 11:787-801, 2002; Garcia de Vinuesa et al. In: Eur J Immunol 29:3216-3224, 1999]. In aged human beings and mice, the reduced levels of expression of CD40 ligand (CD40L) in activated CD4 helper T cells is dramatically reduced [Eaton et al. In: J Exp Med 200:1613-1622, 2004; Dong et al. In: J Gen Virol 84:1623-1628, 2003]. To circumvent the reduction in CD40L expression and the subsequent reduction in immune response in the elderly, we have developed a chimeric vaccine comprised of the CD40L linked to the target antigen, in a replication incompetent adenoviral vector and in booster protein. This review will discuss the implementation the potential use of this approach for the vaccination of the older populations for cancer and infection.
MeSH Terms
- Aging
- Animals
- CD40 Ligand
- Cancer Vaccines
- Humans
- Immunoconjugates
- Infections
- Mice
- Neoplasms
- Vaccines
Adiponectin (ADPN) exerts anti-inflammatory and cardio protective effects and is associated with decreased cardiovascular risk, however its role in patients with chronic kidney disease is unclear. We investigated the correlation between plasma ADPN levels, the progression of CVD and CKD and the inflammatory gene expression profile of peripheral blood mononuclear cells in patients from the NephroPLIC study (a prospective study aimed at addressing the progression of cardiovascular damage in relation to kidney dysfunction). Plasma ADPN levels were directly correlated with age, HDL-C and creatinine, and inversely with BMI, triglycerides and glomerular filtration rate (GFR). Multiple regression analysis identified plasma creatinine and HDL as the independent factors associated with ADPN plasma levels. In peripheral blood mononuclear cells (PBMC), the mRNA expression of MCP-1, CD40, Cox-2, TLR4, PAI-1, TNF alpha, resistin and RAGE was up-regulated in the group with higher GFR and higher ADPN plasma levels compared to that with low GFR and ADPN plasma levels. Patients with similar GFR values showed no differences in the gene expression profile of PBMC although ADPN levels were associated with decreased CRP and IL-6 plasma levels and decreased IMT and heart left ventricular mass. In CKD patients who are not in dialysis ADPN plasma levels are associated with a reduced renal excretory function, but correlate inversely with the determinants of the metabolic syndrome such as glucose, triglycerides and BMI, and directly with HDL. Furthermore, in patients with a similar degree of renal impairment, ADPN plasma levels are associated with a better cardiometabolic profile, despite no significant difference being observed in the gene expression pattern of PBMC.
MeSH Terms
- Adiponectin
- Adult
- Aged
- Aged, 80 and over
- Aging
- Biomarkers
- Cardiovascular Diseases
- Cholesterol, HDL
- Cohort Studies
- Creatinine
- Female
- Gene Expression Profiling
- Glomerular Filtration Rate
- Humans
- Inflammation
- Male
- Metabolic Syndrome
- Middle Aged
- Renal Insufficiency, Chronic
- Young Adult
We analyzed the association between platelet activation, adiponectin, insulin resistance and oxidative stress in aging. In addition, we included American football (AB) players to investigate whether this association is modulated by exercise. Eighty-six old age patients (> or = 65 years old) hospitalized at the nursing institution and 62 AB players were recruited as study subjects. Reactive oxygen metabolites (ROM), soluble CD40 ligand (sCD40L) and adiponectin were estimated with these patients. In comparison to old age, plasma adiponectin levels in AB players were significantly low. In addition, the adiponectin values of elder group (> 80 years) in old age were significantly increased higher than those for younger group (< or = 80 years). There were no differences of sCD40L in two groups. Levels of ROM in AB players were also significantly lower than that in old age. However, the ROM values of younger group in old age were significantly increased higher than those for elder group. The sCD40L also exhibited the same results. There were no significant differences in ROM and adiponectin levels between the high homeostasis model assessment-insulin resistance (HOMA-IR) (> 2.0) and the low HOMA-IR (< or = 2.0). In contrast, in the old age, the sCD40L and ROM levels in the high HOMA-IR group were significantly higher than those in the low HOMA-IR group. In addition, the adiponectin level in the high HOMA-IR group was significantly lower than that in the low HOMA-IR group. Our results suggest that platelet activation, adiponectin and oxidative stress are the very important factors for aging, and the maintenance of exercise could prevent the occurrence of metabolic syndrome or insulin resistance.
MeSH Terms
- Adiponectin
- Aged
- Aging
- Blood Platelets
- Body Mass Index
- Enzyme-Linked Immunosorbent Assay
- Female
- Humans
- Insulin Resistance
- Male
- Obesity
- Reactive Oxygen Species
- Recombinant Fusion Proteins
To determine if soluble CD40 ligand (sCD40L; formally CD154) levels vary with age and to identify age-dependent ranges in healthy pediatric and adult populations. sCD40L was measured in 25 neonates, 74 children (3 months-15 years of age) and 20 adults using an enzyme-linked immunosorbent assay. For age group comparisons, Mann-Whitney tests were performed. Correlation coefficients assessed relationships between plasma and serum sCD40L. Plasma sCD40L levels were higher in neonates than in all other age groups, (P <.001). All grouped pediatric plasma levels were significantly higher than in adults (P < .0001). There were no significant differences in plasma sCD40L between pediatric age groups. Serum levels were significantly higher in neonates than in any other age group (P < .0001). Pediatric and adult serum sCD40L levels were not significantly different. Plasma sCD40L levels are highest at birth and remain higher than those in adults throughout childhood. Reasons for such developmental changes remain to be investigated. Age-appropriate reference ranges should be used when sCD40L is being evaluated in pediatric disorders.
MeSH Terms
- Adolescent
- Adult
- Age Factors
- Aging
- CD40 Ligand
- Child
- Child, Preschool
- Enzyme-Linked Immunosorbent Assay
- Female
- Fetal Blood
- Humans
- Infant
- Infant, Newborn
- Male
- Middle Aged
- Reference Values
To study the effect of seleno-argnine on cellular immunological function in D-gal aging mice. The mice were divided into normal group, model group, low seleno-argnine group(L-SeArg) and high seleno-argnine group (H-SeArg). D-galactose induced aging model was set up by s.c. injection for 42 days, i.g. method was used to add Seleno-argnine. Spleen index(SI) and thymus index (TI) were measured. The ability of Spleen cell multiplication and NK cell killing activity were determined by MTT colorimetry. The changes of CD40 and CD40L expression were observed by immunofluorescent assay. Compared with the model mice, seleno-argnine increased spleen index and thynus index, enhanced the ability of spleen cell multiplication, enhanced the expression of CD40 and CD40L, and accelerated the NK cell killing activity. Between the two seleno-argnine groups, the effect of L-SeArg on cellular immunological function was more obvious in D-gal aging mice.The result were statistic ally significantly compared with the model mice(P<0.01). D-gal injection can decrease the cellular immunological function of mice. Seleno-argnine can activate immune cells, enhance the cellular immunological function of mice, reduce the toxic effect of D-gal and delay the aging process.
MeSH Terms
- Aging
- Animals
- Arginine
- CD40 Antigens
- Cell Proliferation
- Dietary Supplements
- Female
- Fluorescent Antibody Technique
- Galactose
- Gene Expression Regulation
- Killer Cells, Natural
- Male
- Mice
- Selenium
- Spleen
- Thymus Gland
White matter lesions (WML), a common feature in brain ageing, are classified as periventricular (PVL) or deep subcortical (DSCL), depending on their anatomical location. Microglial activation is implicated in a number of neurodegenerative diseases, but the microglial response in WML is poorly characterized and its role in pathogenesis unknown. We have characterized the microglial response in WML and control white matter using immunohistochemistry to markers of microglial activation and of proliferation. WML of brains from an unbiased population-based autopsy cohort (Medical Research Council's Cognitive Function and Ageing Study) were identified by post mortem magnetic resonance imaging and sampled for histology. PVL contain significantly more activated microglia, expressing major histocompatibility complex (MHC) class II and the costimulatory molecules B7-2 and CD40, than either control white matter (WM) or DSCL. Furthermore, we show that significantly more microglia express the replication licensing protein minichromosome maintenance protein 2 within PVL, suggesting this is a more proliferation-permissive environment than DSCL. Although microglial activation occurs in both PVL and DSCL, our findings suggest a difference in pathogenesis between these lesion-types: the ramified, activated microglia associated with PVL may reflect immune activation resulting from disruption of the blood brain barrier, while the microglia within DSCL may reflect an innate, amoeboid phagocytic phenotype. We also show that microglia in control WM from lesional cases express significantly more MHC II than control WM from nonlesional ageing brain, suggesting that WML occur in a 'field-effect' of abnormal WM.
MeSH Terms
- Aged
- Aged, 80 and over
- Aging
- B7-2 Antigen
- Brain
- CD40 Antigens
- CD40 Ligand
- Cell Proliferation
- Female
- Histocompatibility Antigens Class II
- Humans
- Immunohistochemistry
- Ki-67 Antigen
- Male
- Microglia
- Middle Aged
As potent suppressors of immune responses to self- and foreign-antigens, Foxp3( ) Treg cells are suspected to be involved in immunosuppression leading to cancer, neurodegeneration and infection. Since ageing is associated with increased incidence of these diseases, we compared Treg activity in blood, lymphoid organs and lungs of young (5-6 months) and old (21-22 months) mice. Both the proportion and absolute number of Foxp3( ) CD4( ) Treg cells increased with age in secondary lymphoid organs but not in blood and lungs as compared to Foxp3(-) CD4( ) T cells. Although numbers of thymic and naïve conventional T and Treg cells decreased with age, Treg cells with memory/effector phenotype increased disproportionately in peripheral lymphoid tissues. In addition, CD40 and CD86 co-stimulatory molecule expression by lymph node dendritic cells was impaired in old mice and could be restored to levels of young mice by inactivating Treg cells with anti-CD25 monoclonal antibodies. These findings have important implications for the understanding of age-related immune dysfunction.
MeSH Terms
- Age Factors
- Aging
- Animals
- B7-2 Antigen
- CD4-Positive T-Lymphocytes
- CD40 Antigens
- Cell Proliferation
- Cyclic AMP
- Dendritic Cells
- Forkhead Transcription Factors
- Immune Tolerance
- Immunologic Memory
- Interleukin-2 Receptor alpha Subunit
- Leukocytes, Mononuclear
- Lung
- Lymph Nodes
- Male
- Mice
- Mice, Inbred C57BL
- Spleen
- T-Lymphocytes, Regulatory
- Thymus Gland
The age-related deficit in long-term potentiation (LTP) in the dentate gyrus is positively correlated with hippocampal concentration of the pro-inflammatory cytokine, interleukin-1beta (IL-1beta). Previous evidence also indicates that the inhibition of LTP induced by intracerebroventricular injection of amyloid-beta(1-40) (Abeta) is accompanied by increased hippocampal IL-1beta concentration and IL-1beta-stimulated signalling, specifically activation of the stress-activated protein kinase, c-jun N-terminal kinase (JNK). We considered that the underlying age-related neuroinflammation may render older rats more susceptible to Abeta administration and, to investigate this, young, middle-aged and aged rats were injected intracerebroventricularly with Abeta or vehicle. Hippocampal IL-1beta concentration, JNK phosphorylation, expression of the putative Abeta receptor, Receptor for advanced glycation end products (RAGE) and the microglial cell surface marker, CD40 were assessed. We report that Abeta inhibited LTP in a concentration-dependent manner in young rats and that this was accompanied by concentration-dependent increases in hippocampal IL-1beta and expression of phosphorylated JNK, RAGE and CD40. While 20 micromol/L Abeta exerted no significant effect on LTP in young rats, it inhibited LTP in middle-aged and aged rats and the increased vulnerability of aged rats was associated with increased IL-1beta concentration. Treatment of rats with eicosapentaenoic acid attenuated the inhibitory effect of 60 micromol/L Abeta on LTP in young rats and the effect of 20 micromol/L Abeta in middle-aged and aged rats. We present evidence which indicates that the effect of eicosapentaenoic acid may be linked with its ability to stimulate activation of peroxisome proliferator-activated receptor gamma.
MeSH Terms
- Age Factors
- Aging
- Amyloid beta-Peptides
- Animals
- Animals, Newborn
- Anti-Inflammatory Agents
- CD40 Antigens
- Cells, Cultured
- Dose-Response Relationship, Drug
- Eicosapentaenoic Acid
- Encephalitis
- Hippocampus
- Injections, Intraventricular
- Interleukin-1beta
- JNK Mitogen-Activated Protein Kinases
- Long-Term Potentiation
- Male
- Neuroprotective Agents
- Phosphorylation
- RNA, Messenger
- Rats
- Rats, Wistar
- Receptor for Advanced Glycation End Products
- Receptors, Immunologic
- Up-Regulation
Polyclonal B cell activation is a hallmark of the immune dysregulation in New Zealand Black (NZB) mice. We have previously shown that the splenic B cell activation is associated with increased CD80 expression. Here we show that abnormal expansions of CD80-expressing GC, CD5( ), marginal zone (MZ) precursor and MZ B cells produce this increase. To investigate the role of BCR engagement in the generation and activation of these populations, a non-self-reactive Ig Tg was introduced onto the NZB background. NZB Ig-Tg mice lacked Tg CD5( ) and peanut agglutinin( ) B cells, confirming the role of endogenous Ag in their selection. Although the increased proportion of MZ B cells was retained in NZB Ig-Tg mice, CD80 expression on these cells was reduced as compared to non-Tg NZB mice, suggesting a role for BCR engagement with endogenous Ag in their activation. Examination of CD40L-knockout NZB mice showed no difference in the abnormal activation or selection of the B cell populations, with the exception of GC cells, as compared to wild-type NZB mice. Thus, polyclonal B cell activation in NZB mice does not require CD40 engagement, but results, in part, from dysregulated BCR-specific mechanisms.
MeSH Terms
- Aging
- Animals
- B-Lymphocytes
- CD40 Ligand
- Cell Differentiation
- Cell Proliferation
- Lymphocyte Activation
- Lymphocyte Count
- Mice
- Mice, Inbred NZB
- Receptors, Antigen, B-Cell
We previously demonstrated that in vitro stimulated splenic B cells from senescent mice are deficient in production of multiple class switch isotypes, class switch recombination (CSR), induction of the E2A-encoded transcription factor E47, and activation-induced cytidine deaminase (AID) which is necessary for CSR and somatic hypermutation. Both anti-CD40 as well as BAFF have been shown to be able to induce CSR. We have investigated the ability of BAFF/IL-4, as compared to anti-CD40/IL-4, to induce CSR to gamma(1) in splenic B cells from young and old mice. We found that anti-CD40/IL-4 is a better CSR stimulus than BAFF/IL-4 in young B cells, as measured by RT-PCR of post-switch transcripts and flow cytometry. CSR is reduced in old B cells and this is independent of the stimulus. AID and gamma(1)PSTs are significantly reduced in old B cells stimulated with anti-CD40/IL-4, but only slightly reduced with BAFF/IL-4. BAFF receptor mRNA expression (BAFF-R, TACI, and BCMA) is not affected by aging. The age-related decrease in CSR induced by anti-CD40/IL-4 is primarily associated with a decrease in E47, whereas the less affected response to BAFF/IL-4 is associated with decreases in both E47 and NF-kappaB. Therefore, NF-kappaB is not involved in the decreased response of old B cells to anti-CD40/IL-4. These differences in B cell responses to CD40/IL-4 and BAFF/IL-4 may help to explain the maintenance of TI vs TD responses in senescent mice.
MeSH Terms
- Aging
- Animals
- Antibodies
- B-Cell Activating Factor
- B-Cell Activation Factor Receptor
- B-Cell Maturation Antigen
- B-Lymphocytes
- CD40 Antigens
- Cells, Cultured
- Cytidine Deaminase
- Female
- Immunoglobulin Class Switching
- Immunoglobulin E
- Immunoglobulin G
- Interleukin-4
- Male
- Mice
- Mice, Inbred BALB C
- RNA, Messenger
- Spleen
- Transcription Factors
- Transmembrane Activator and CAML Interactor Protein
It is well established that inflammatory changes contribute to brain ageing, and an increased concentration of proinflammatory cytokine, interleukin-1beta (IL-1beta), has been reported in the aged brain associated with a deficit in long-term potentiation (LTP) in rat hippocampus. The precise age at which changes are initiated is unclear. In this study, we investigate parallel changes in markers of inflammation and LTP in 3-, 9- and 15-month-old rats. We report evidence of increased hippocampal concentrations of the proinflammatory cytokines IL-1alpha, IL-18 and interferon-gamma (IFNgamma), which are accompanied by deficits in LTP in the older rats. We also show an increase in expression of markers of microglial activation, CD86, CD40 and intercellular adhesion molecules (ICAM). Associated with these changes, we observed a significant impairment of hippocampal LTP in the same rats. The importance of microglial activation in the attenuation of long-term potentiation (LTP) was demonstrated using an inhibitor of microglial activation, minocycline; partial restoration of LTP in 15-month-old rats was observed following administration of minocycline. We propose that signs of neuroinflammation are observed in middle age and that these changes, which are characterized by microglial activation, may be triggered by IL-18.
MeSH Terms
- Aging
- Animals
- Anti-Inflammatory Agents
- B7-2 Antigen
- Biomarkers
- CD40 Antigens
- Cytokines
- Dentate Gyrus
- Encephalitis
- Gliosis
- Hippocampus
- Intercellular Adhesion Molecule-1
- Interferon-gamma
- Interleukin-18
- Interleukin-1alpha
- Long-Term Potentiation
- Male
- Memory Disorders
- Microglia
- Minocycline
- Rats
- Rats, Wistar
Despite the importance of thymic stromal cells to T-cell development, relatively little is known about their biology. Here, we use single-cell analysis of stromal cells to analyze extensive changes in the number and composition of thymic stroma throughout life, revealing a surprisingly dynamic population. Phenotypic progression of thymic epithelial subsets was assessed at high resolution in young mice to provide a developmental framework. The cellular and molecular requirements of adult epithelium were studied, using various mutant mice to demonstrate new cross talk checkpoints dependent on RelB in the cortex and CD40 in the medulla. With the use of Ki67 and BrdU labeling, the turnover of thymic epithelium was found to be rapid, but then diminished on thymic involution. The various defects in stromal turnover and composition that accompanied involution were rapidly reversed following sex steroid ablation. Unexpectedly, mature cortical and medullary epithelium showed a potent capacity to stimulate naive T cells, comparable to that of thymic dendritic cells. Overall, these studies show that the thymic stroma is a surprisingly dynamic population and may have a more direct role in negative selection than previously thought.
MeSH Terms
- Aging
- Animals
- CD40 Antigens
- Dendritic Cells
- Epithelial Cells
- Ki-67 Antigen
- Mice
- Mice, Mutant Strains
- Stromal Cells
- T-Lymphocytes
- Thymus Gland
- Transcription Factor RelB
There is substantial evidence that both inflammation and oxidative damage contribute to the pathogenesis of motor neuron degeneration in the G93A SOD1 transgenic mouse model of amyotrophic lateral sclerosis (ALS). Celastrol is a natural product from Southern China, which exerts potent anti-inflammatory and antioxidative effects. It also acts potently to increase expression of heat shock proteins including HSP70. We administered it in the diet to G93A SOD1 mice starting at 30 days of age. Celastrol treatment significantly improved weight loss, motor performance and delayed the onset of ALS. Survival of celastrol-treated G93A mice increased by 9.4% and 13% for 2 mg/kg/day and 8 mg/kg/day doses, respectively. Cell counts of lumbar spinal cord neurons confirmed a protective effect, i.e. 30% increase in neuronal number in the lumbar spinal cords of celastrol-treated animals. Celastrol treatment reduced TNF-alpha, iNOS, CD40, and GFAP immunoreactivity in the lumbar spinal cord sections of celastrol-treated G93A mice compared to untreated G93A mice. TNF-alpha immunoreactivity co-localized with SMI-32 (neuronal marker) and GFAP (astrocyte marker). HSP70 immunoreactivity was increased in lumbar spinal cord neurons of celastrol-treated G93A mice. Celastrol has been widely used in treating inflammatory diseases in man, and is well tolerated; therefore, it may be a promising therapeutic candidate for the treatment of human ALS.
MeSH Terms
- Amyotrophic Lateral Sclerosis
- Animals
- Astrocytes
- CD40 Antigens
- Cell Count
- Cell Death
- Female
- Fluorescent Antibody Technique, Indirect
- Glial Fibrillary Acidic Protein
- HSP70 Heat-Shock Proteins
- Longevity
- Mice
- Mice, Transgenic
- Motor Neurons
- Neuroglia
- Neurons
- Neuroprotective Agents
- Postural Balance
- Psychomotor Performance
- Superoxide Dismutase
- Superoxide Dismutase-1
- Survival Analysis
- Triterpenes
- Tumor Necrosis Factor-alpha
- Up-Regulation
We analyzed the activation and function of dendritic cells (DCs) in the spleens of diseased, lupus-prone NZM2410 and NZB-W/F1 mice and age-matched BALB/c and C57BL/6 control mice. Lupus DCs showed an altered ex vivo costimulatory profile, with a significant increase in the expression of CD40, decreased expression of CD80 and CD54, and normal expression of CD86. DCs from young lupus-prone NZM2410 mice, before the development of the disease, expressed normal levels of CD80 and CD86 but already overexpressed CD40. The increase in CD40-positive cells was specific for DCs and involved the subset of myeloid and CD8alpha DCs before disease onset, with a small involvement of plasmacytoid DCs in diseased mice. In vitro data from bone marrow-derived DCs and splenic myeloid DCs suggest that the overexpression of CD40 is not due to a primary alteration of CD40 regulation in DCs but rather to an extrinsic stimulus. Our analyses suggest that the defect of CD80 in NZM2410 and NZB-W/F1 mice, which closely resembles the costimulatory defect found in DCs from humans with systemic lupus erythematosus, is linked to the autoimmune disease. The increase in CD40 may instead participate in disease pathogenesis, being present months before any sign of autoimmunity, and its downregulation should be explored as an alternative to treatment with anti-CD40 ligand in lupus.
MeSH Terms
- Aging
- Animals
- B7-1 Antigen
- B7-2 Antigen
- CD40 Antigens
- Dendritic Cells
- Disease Susceptibility
- Lupus Vulgaris
- Mice
- Mice, Inbred Strains
- Phenotype
- Severity of Illness Index
- Spleen
The CXCL1 chemokines, macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (KC), have been shown to play a role in a number of pathophysiological disease states including endotoxin-induced inflammation and bacterial meningitis. While the expression of these chemokines has been identified in a variety of cell types in the mouse, little is known about their expression with murine B-lymphocytes. Here, we demonstrate that highly purified murine splenic B cells are capable of expressing both MIP-2 and KC protein and mRNA upon activation with lipopolysaccharide (LPS) but not in response to anti-micro and anti-CD40 in combination with interleukin-4 (IL-4) stimulation. Moreover, these chemokines are expressed at higher levels in B cells derived from young (4 m) compared to old (24-29 m) mice. Upon fractionation into distinct B-cell subsets, we found that the expression of MIP-2 and KC by aged follicular (FO) B cells is significantly decreased when compared to the same cells from younger mice, while only MIP-2 production was found to be diminished in aged marginal zone (MZ) B cells. Interestingly, MIP-2 and KC production by newly formed (NF) B cells did not significantly differ with age. Moreover, the potential relevance of these findings is supported by the poor ability of LPS-activated aged B cells to specifically mediate CXCL1-dependent leukocyte recruitment when compared to younger B cells. Overall, the decreased expression of CXCL1 chemokines by aged B cells in response to LPS may have potential implications on the secondary recruitment of leukocytes to sites of microbial infections and inflammation possibly contributing to the increased susceptibility of older subjects to pathogen challenge.
MeSH Terms
- Aging
- Animals
- Antibodies, Anti-Idiotypic
- Antibodies, Monoclonal
- B-Lymphocyte Subsets
- B-Lymphocytes
- CD40 Antigens
- Cells, Cultured
- Chemokine CXCL1
- Chemokine CXCL2
- Chemokines
- Chemokines, CXC
- Immunoglobulin M
- Intercellular Signaling Peptides and Proteins
- Lipopolysaccharides
- Mice
- Mice, Inbred C57BL
- Specific Pathogen-Free Organisms
- Spleen
We have shown that, when an amyloid-beta peptide (Abeta) overproducing transgenic mouse model (PSAPP) of Alzheimer's disease (AD) is treated with a depleting antibody against CD40L, it causes marked attenuation of Abeta pathology associated with decreased amyloidogenic processing of amyloid precursor protein (APP) and increased cerebral clearance of Abeta. Here, we report that, when PSAPP mice receive a regimen of anti-CD40L antibody commencing at an age associated with initial Abeta deposition, they demonstrate superior spatial memory on the standard water maze and radial arm water maze tasks, as well as exhibiting superior non-spatial memory in the object recognition test, as compared to control PSAPP mice. Furthermore, PSAPP mice treated with an anti-CD40L antibody regimen commencing at an age associated with extensive Abeta deposition demonstrate superior spatial memory on the standard water maze task, as compared to control PSAPP mice. Disruption of CD40L activity has beneficial effects on pathology and cognitive behavior in the PSAPP mouse model, providing support for the therapeutic potential of interrupting the CD40-CD40L interaction in AD.
MeSH Terms
- Aging
- Alzheimer Disease
- Amyloid beta-Peptides
- Animals
- Behavior, Animal
- CD40 Antigens
- CD40 Ligand
- Cognition
- Disease Models, Animal
- Female
- Male
- Maze Learning
- Memory
- Mice
- Mice, Transgenic
- Psychomotor Performance
- Spatial Behavior
X linked hyper-IgM (XHIM) is a primary immunodeficiency caused by mutations in the tumour necrosis factor superfamily 5 gene, TNFSF5, also known as the CD40 ligand (CD40L) gene. Patients often present with recurrent infections, and confirmation of a diagnosis of XHIM enables appropriate therapeutic interventions, including replacement immunoglobulin, antibiotics, and bone marrow transplantation. To review and optimise the institution's diagnostic strategy for XHIM. Samples from 65 boys were referred to this centre for further investigation of suspected XHIM. The results, which included a flow cytometric whole blood assay for CD40L expression followed by mutation analysis in selected patients, were reviewed. Twenty one patients failed to express CD40L and TNFSF5 mutations were found in 20 of these patients. In contrast, no TNFSF5 mutations were found in 16 patients with weak expression of CD40L. Interestingly, one quarter of patients with confirmed XHIM who had TNFSF5 mutations had low concentrations of IgG, IgA, and IgM. Most of the remaining patients with XHIM had the classic pattern of normal or raised IgM with low concentrations of IgA and IgG. This study demonstrates the usefulness of the whole blood staining method as a rapid screen to select patients for subsequent TNFSF5 mutation analysis, and shows the benefits of a unified protein/genetic diagnostic strategy.
MeSH Terms
- Adolescent
- Adult
- Aging
- CD40 Ligand
- Cells, Cultured
- Child
- Child, Preschool
- DNA Mutational Analysis
- Genetic Diseases, X-Linked
- Humans
- Hypergammaglobulinemia
- Immunoglobulin M
- Immunoglobulins
- Infant
- Middle Aged
- Patient Selection
Ageing is characterized by numerous changes in lymphocyte subpopulations. In the present paper we have focused on B cells carrying the surface markers CD27, CD5 and CD40. CD27 is considered a marker of primed (memory) cells and its engagement promotes the differentiation of memory B cells into plasma cells. CD5 is expressed on B1 cells, which are considered to be responsible for T cell-independent antibody production other than autoantibodies. The CD40 molecule binds CD40L (CD154) and is necessary for T-dependent antibody responses. Here we show that the absolute number of CD5 and CD40 B cells is decreased in the elderly, while CD27 B lymphocytes only marginally decrease in centenarians. However, there is a decrease of the percentage of CD5 B cells, an increase of CD27 B cells, while CD40 does not change significantly. These data, together with the increased number of NK cells during aging, suggest different regulation of antibody production in the elderly which might be another example of immune remodeling with aging, based on interactions between human B and NK cells.
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Aging
- B-Lymphocytes
- Biomarkers
- CD40 Antigens
- CD5 Antigens
- Humans
- Lymphocyte Count
- Middle Aged
- Tumor Necrosis Factor Receptor Superfamily, Member 7
In the present paper, we have investigated the effects of aging on the expression and function of the E2A-encoded transcription factor E47 in splenic B lymphocytes, unactivated or activated with different stimuli (LPS, anti-CD40, anti-IgM, alone or in combination with IL-4). Results indicate that unstimulated splenic B cells show very low E47 protein levels as well as E47 DNA-binding activity and that, upon B cell activation, E47 expression and DNA-binding activity are strongly induced in young and, to a significantly lesser extent, in old mice. The level of E47 protein expression in stimulated splenic B cells was found significantly higher in young than in old mice, suggesting that DNA-binding activity correlates with protein expression. These results altogether suggest that the reduced expression of the transcriptional regulator E47 could help explain the reduced B cell functions in aging mice.
MeSH Terms
- Aging
- Animals
- B-Lymphocytes
- CD40 Antigens
- Cell Division
- DNA-Binding Proteins
- Down-Regulation
- Female
- Gene Expression
- Immunoglobulin M
- Lipopolysaccharides
- Male
- Mice
- Mice, Inbred BALB C
- Spleen
- Stimulation, Chemical
- TCF Transcription Factors
- Transcription Factor 7-Like 1 Protein
- Transcription Factors
Binding of CD154 to its receptor, CD40, provides costimulation for mature B cell activation and differentiation in response to Ag receptor signals. In mice, early B cell precursors express CD40, but its function at this stage is unknown. We examined the effects of CD40 ligation during B cell ontogeny in transgenic mice constitutively expressing CD154 on B cells (kappaEP-CD154). Precursors beyond pro-B cells were absent in adult bone marrow but were increased in the fetal liver. Newborn kappaEP-CD154 mice had largely increased numbers of peripheral B cells, which were CD154 , and that 36 h after birth expressed high surface levels of CD23 and MHC class II, resembling activated mature B cells. Nevertheless, kappaEP-CD154 mice were hypogammaglobulinemic, indicating that the expanded population of apparently activated B cells was nonfunctional. Further analysis revealed that soon after birth, kappaEP-CD154 mice-derived B cells became CD5 /Fas , after which progressively decreased in the periphery in a CD154-CD40-dependent manner. These results indicate that CD40 ligation during B cell ontogeny induces negative selection characterized by either hyporesponsiveness or an arrest in maturation depending on the time of analysis and the anatomic site studied.
MeSH Terms
- Aging
- Animals
- B-Lymphocyte Subsets
- Bone Marrow Cells
- CD40 Antigens
- CD40 Ligand
- CD5 Antigens
- Cell Differentiation
- Cell Division
- Clonal Anergy
- Fetus
- Immunophenotyping
- Ligands
- Liver
- Lymphocyte Activation
- Lymphocyte Count
- Lymphopenia
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Stem Cells
- fas Receptor
Analysis of expression of CD38, CD45R (B220), IgM and IgD on splenic B lymphocytes from mice of different ages demonstrated CD38 on both immature (B220( ), BCR(-)) and mature (B220( ), BCR( )) B lymphocytes. Similarly, CD38 is expressed as early as B220 on the surface of progenitor B cells in the bone marrow. In spite of expressing of CD38 and IgM, neonatal B cells, in contrast to the adult, failed to proliferate to either anti-CD38 or anti-IgM cross-linking when IL-4 was present. They did, however, respond to LPS and anti-CD40, and by 2 weeks of age they began to respond to anti-CD38 and anti-IgM, reaching adult B cell levels by 4 weeks. Although the distribution of CD38 on adult B cells from most different lymphoid compartments was broadly similar, significantly higher levels of CD38 were expressed on peritoneal B lymphocytes. A detailed analysis, using IgM / IgD ratio and staining with anti-CD5 confirmed that B1 lymphocytes were expressing a high level of CD38. Interestingly, both immature B cells and peritoneal B1 lymphocytes were unresponsive to anti-CD38. However, they were activated by LPS or anti-CD40.
MeSH Terms
- ADP-ribosyl Cyclase
- ADP-ribosyl Cyclase 1
- Aging
- Animals
- Antibodies
- Antigens, CD
- Antigens, Differentiation
- B-Lymphocytes
- Bone Marrow Cells
- CD40 Antigens
- Cell Differentiation
- Cell Division
- Female
- Flow Cytometry
- Immunoglobulin D
- Immunoglobulin M
- Lipopolysaccharides
- Lymphocyte Activation
- Membrane Glycoproteins
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C3H
- Mice, Inbred C57BL
- NAD Nucleosidase
- Peritoneal Cavity
- Peyer's Patches
- Receptor Aggregation
- Spleen
- Stem Cells
Lupus disease is marked by B lymphocyte hyperactivity and the production of Abs to dsDNA. The production of these anti-dsDNA Abs is T lymphocyte dependent. However, it is not clear how CD4 T lymphocytes provide help for B lymphocytes to produce IgG anti-dsDNA Abs. One possible mechanism is suggested by studies showing that human patients with systemic lupus erythematosus and lupus mice have increased numbers of CD40 ligand (CD40L) T and B lymphocytes. The results described in this study reveal that young, clinically healthy lupus-prone New Zealand Black x New Zealand White F1 (BWF1) mice have naive CD4 T cells with preformed CD40L. These cells contribute to a brisk response to immunization and to the production of anti-dsDNA Abs. In vitro experiments revealed that CD4 T cells with preformed CD40L could, upon stimulation, provide antiapoptotic signals for B cells but could not induce proliferation or reduce activation threshold. These results suggest that the direct target cells for the effect of T cells with preformed CD40L in lupus may not be B lymphocytes.
MeSH Terms
- Aging
- Animals
- Antibodies, Antinuclear
- Antigens
- B-Lymphocytes
- CD4-Positive T-Lymphocytes
- CD40 Ligand
- Cell Aggregation
- Cell Differentiation
- Cell Division
- Cell Survival
- Cells, Cultured
- Coculture Techniques
- Crosses, Genetic
- Cytoplasm
- DNA
- Genetic Predisposition to Disease
- Immunization
- Immunophenotyping
- Kinetics
- Lupus Erythematosus, Systemic
- Lymphocyte Activation
- Lymphocyte Cooperation
- Lymphocyte Count
- Mice
- Mice, Inbred CBA
- Mice, Inbred NZB
- Spleen
- T-Lymphocyte Subsets
- Up-Regulation
A deficiency of neonatal T lymphocytes to express CD154 antigen in response to ionomycin and phorbol 12-myrsistate 13-acetate (PMA) stimulation or after CD3 cross-linking has been described. In the present report we describe that CD45RA newborn cells are able to synthesize and express CD154 at similar or even higher levels than adult cells in response to ionomycin and cAMP-elevating agents which trigger the protein kinase A (PKA) -mediated metabolic pathway. Peak CD154 protein concentrations in newborn cells were found between 4 and 8 hr after stimulation with ionomycin and dibutyryl cAMP. These agents, however, did not induce expression of the early activation antigen CD69. Surface levels of CD154 did not correlate with specific mRNA concentration, indicating that dibutyryl cAMP up-regulates CD154 by acting at a post-transcriptional stage. The CD154 antigen induced by PKA activation of newborn cells was functional, since upon binding to CD40 on B lymphocytes in the presence of interleukin-4 (IL-4), it promoted immunoglobulin heavy-class switching to IgE. We also found a different pattern of cytokine production between neonatal and adult CD4 T cells. In response to ionomycin and dibutyryl cAMP, cord blood cells were more prone than adult lymphocytes to secrete the T helper type 2-derived immunosuppressive cytokines IL-4 and IL-10. Taking into account that the feto-maternal environment is rich in cAMP-elevating agents, the reduced risk of graft versus host disease associated with cord blood trasplantation, as compared with the risk with adult bone marrow cell transplants, may be due to the bias of neonatal cells to differentiate towards the T helper type 2 functional cell subset.
MeSH Terms
- Adult
- Aging
- Bucladesine
- CD4-Positive T-Lymphocytes
- CD40 Antigens
- CD40 Ligand
- Cell Culture Techniques
- Cyclic AMP
- Cyclic AMP-Dependent Protein Kinases
- Cytokines
- Fetal Blood
- Humans
- Immunophenotyping
- Infant, Newborn
- Ionomycin
- Ligands
- Membrane Glycoproteins
Age-related changes in functional subsets of lymphocytes may influence the potential to build up immune responses. In particular, the capacity of tonsillar lymphocytes to counter infections may be altered during ageing. In order to address this question we investigated the proportional distribution of several subsets of tonsillar T and B cells with regard to ageing. Tonsils were derived from 119 patients between 2 and 65 years of age. Lymphocyte subsets were monitored by three-colour fluorescence of relevant CD markers in flow cytometry. As a general tendency the percentage of CD3 T cells steadily increased whereas that of CD19 B cells decreased at the same time. No significant differences were observed between lymphocytes of patients with and without inflammatory history of the tonsils. The percentage of CD8 T cells declined whereas that of CD4 T cells increased during the same time span. CD45RA T cells increased during the first two decades of life and gradually decreased thereafter. In contrast, CD45RO T cells showed an opposite trend. No differences were seen in the population of CD3-/CD56 natural killer (NK) cells. The mature B cell marker CD40 showed no significant changes during ageing. However, CD38 B cells, representing B cells of late maturation stages, dramatically declined up to the age of 65. In a similar manner the CD5 subpopulation of B cells decreased during ageing. Substantial changes in major tonsillar T and B cell populations as shown in this study may have an impact on the ageing process of the immune system.
MeSH Terms
- Adolescent
- Adult
- Aged
- Aging
- Antigens, CD
- B-Lymphocyte Subsets
- Child
- Child, Preschool
- Flow Cytometry
- Humans
- Hyperplasia
- Middle Aged
- Palatine Tonsil
- Respiratory Sounds
- Sleep Apnea Syndromes
- T-Lymphocyte Subsets
- Tonsillitis
Defects involving cellular expression of activation molecules, cell mediated immune response and natural killer (NK) activity are commonly observed in the elderly. Herein, data are reported on the evaluation of IL-12 production by old subjects. IL-12 is, actually, considered the key molecule for the induction of a T helper 1 (Th1) -type and NK response. IL-12 production from old subjects peripheral blood mononuclear cells (PBMNC) was evaluated using T-independent (bacterial lipopolysaccharide, LPS) or -dependent (phytoemagglutinin, PHA; immobilized anti-CD3 monoclonal antibodies, anti-CD3) mitogens. The IL-12 production after LPS stimulation was not reduced in cultures from old subjects when compared to that from young ones. On the contrary, IL-12 production by PHA or anti-CD3 stimulated PBMNC from old subjects was decreased. Furthermore, we have demonstrated a reduced CD40 and CD40 ligand (CD40L) expression on PBMNC from old subjects. This finding fits very well with the reduced cytokine production observed in the T-dependent stimulation systems, being the CD40-CD40L interaction mandatory for an efficient IL-12 production. All together, these results seem to suggest that defects in cell expression of activation molecules can affect the IL-12 secretion and in consequence other Th1-type cytokines.
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Aging
- CD40 Antigens
- CD40 Ligand
- Cells, Cultured
- Female
- Humans
- Interleukin-12
- Leukocytes, Mononuclear
- Lipopolysaccharides
- Male
- Membrane Glycoproteins
- Mitogens
- Phytohemagglutinins
Hyper-IgM syndrome represents a diverse group of immunodeficiencies characterized by normal or high serum IgM concentrations with decreased or absent IgG, IgA, and IgE. The X-linked form of hyper-IgM syndrome is caused by mutations in the CD40 ligand gene, preventing its expression on activated T cells. The CD40 ligand--CD40 interaction is critical for effective isotype switching and for initiating antigen-specific Tf cell responses. In addition to recurrent pyogenic infections, patients with the CD40L defect also have opportunistic infections. An increased proportion of circulating gamma-delta T cells, shown to be important early during primary infections, has been demonstrated in numerous infectious diseases including toxoplasmosis. Here, we report a patient with hyper-IgM syndrome and CNS toxoplasmosis, who showed a marked increase in gamma-delta T cells in his peripheral blood and who has responded well to treatment of his toxoplasmosis and to high-dose immunoglobulin replacement therapy.
MeSH Terms
- Aging
- Animals
- Brain
- CD40 Antigens
- Central Nervous System Infections
- Child
- Flow Cytometry
- Humans
- Hypergammaglobulinemia
- Immunoglobulin M
- Immunoglobulins
- Immunologic Deficiency Syndromes
- Lymphocyte Activation
- Magnetic Resonance Imaging
- Male
- T-Lymphocytes
- Toxoplasma
- Toxoplasmosis
The aging immune system is characterized by a progressive decline in the responsiveness to exogenous antigens and tumors in combination with a paradoxical increase in autoimmunity. From a clinical viewpoint, deficiencies in antibody responses to exogenous antigens, such as vaccines, have a major impact and may reflect intrinsic B cell defects or altered performance of helper T cells. Here we describe that aging is associated with the emergence of an unusual CD4 T cell subset characterized by the loss of CD28 expression. CD28 is the major costimulatory molecule required to complement signaling through the antigen receptor for complete T cell activation. CD4 CD28- T cells are long-lived, typically undergo clonal expansion in vivo, and react to autoantigens in vitro. Despite the deficiency of CD28, these unusual T cells remain functionally active and produce high concentrations of interferon-gamma (IFN-gamma) and interleukin-2 (IL-2). The loss of CD28 expression is correlated with a lack of CD40 ligand expression rendering these CD4 T cells incapable of promoting B cell differentiation and immunoglobulin secretion. Aging-related accumulation of CD4 CD28- T cells should result in an immune compartment skewed towards autoreactive responses and away from the generation of high-affinity B cell responses against exogenous antigens. We propose that the emergence of CD28-deficient CD4 T cells in the elderly can partially explain age-specific aberrations in immune responsiveness.
MeSH Terms
- Aging
- Arthritis, Rheumatoid
- CD28 Antigens
- CD4-Positive T-Lymphocytes
- Cohort Studies
- Cytokines
- Humans
- Immune System
- T-Lymphocytes, Helper-Inducer
The immune system of aged mice produces antibodies that are characterized by low affinity, diminished protection against infections and autoreactivity. It has been shown that these antibodies may be encoded by different immunoglobulin V genes and that the mechanism of somatic hypermutation in the V genes is inefficient. Studies on scid mice reconstituted with B and T cells from donors of different ages suggested that both lymphocyte subsets may contribute to the age-related changes in antibody repertoire. With help provided by T cells from young mice, the response to a hapten, nitrophenyl(acetyl), became gradually dominated by B-cell clones that rearranged a particular germline VH gene (V186.2). However, help from the aged T cells resulted in a heterogeneous response of B cells expressing many different V segments. Analysis of discrete foci of primary antibody-forming cells suggested that the aged T-helper cells are unable to govern the normally-occurring competition between the B-cell clones that have different affinities for the hapten. It is proposed that a signaling disequilibrium from the aged T cells, which provide less efficient help in quantitative terms, supports the growth of low-affinity B cells. This process may be exacerbated due to the apparent hyperactivity of aged B cells to CD40-mediated mitogenic signal.
MeSH Terms
- Aging
- Animals
- Antibodies
- B-Lymphocytes
- Cellular Senescence
- Clone Cells
- Humans
- Mice
- T-Lymphocytes
- T-Lymphocytes, Helper-Inducer
The biological basis for reduced Ig production by naive newborn B cells compared to adult peripheral blood B cells is not fully understood. In a Con A IL-2 T cell-dependent system using "competent" adult T cells, adult B cells produced large amounts of IgM, IgG, and IgA, while cord B cells were restricted to low levels of only IgM production. Cord B cell activation was also diminished. The contribution of specific B-T cell contact-mediated events to the diminished cord B cell response in this system, using mAbs to CD40, CD28, CD80, and CD72, were investigated, as well as regulation of B cell Ig production by cytokines. alphaCD72 ligation increased cord B cell activation and IgM production, but did not affect adult B cells. Blocking alphaCD40 mAb inhibited cord B cell Ig production completely, but only partly inhibited adult B cell Ig production even at high concentration, suggesting a greater sensitivity of cord B cells to disruption of the CD40-CD40L interaction. Addition of IL-10 did not increase cord B cell Ig production, while adult B cell Ig production was increased. However, combined addition of IL-10 and alphaCD72 significantly increased cord B cell Ig production over that in the presence of either alphaCD72 or IL-10 alone, but had no effect on adult B cells over that of IL-10 alone. These data suggest that the diminished T cell-dependent response of cord B cells is due to reduced or absent CD72 ligation. CD72 ligation plays an important role in the induction of primary responses by naive B cells. CD72 modulation of naive B cell sensitivity to IL-10 stimulation may have implications in the induction of class switch, which is deficient in newborn B cells. Since all T cells express CD5 constitutively, these data also suggest the existence of another ligand for CD72.
MeSH Terms
- Adult
- Aging
- Antibodies, Monoclonal
- Antibody Formation
- Antigens, CD
- Antigens, Differentiation, B-Lymphocyte
- B-Lymphocytes
- Cell Differentiation
- Cells, Cultured
- Concanavalin A
- Cytokines
- Fetal Blood
- Histocompatibility Antigens Class II
- Humans
- Interleukin-10
- Interleukin-2
- Lymphocyte Activation
- Lymphocyte Cooperation
- Middle Aged
- T-Lymphocytes
Dendritic cells are antigen-presenting cells (APC), which are crucial for the initiation of an immune response. In spite of the well known decline of immune function in old age, no information is yet available on whether dendritic cells are also affected by the ageing process. It was therefore the aim of this study to compare peripheral blood dendritic cells (DC) from old and young healthy individuals. Using granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4, DC were propagated from peripheral blood mononuclear cells (PBMC). The obtained cell populations had a typical dendritic morphology and expressed HLA class I and class II, CD23, CD32, CD40, CD44 and CD54, but not CD3 and CD19. Larger numbers of DC were obtained from old individuals than from young ones in spite of a similar expression pattern of surface molecules. DC from aged persons also survived better under in vitro culture conditions. When tested for their antigen-presenting capacity, DC from young and old individuals were equally effective in inducing the proliferation of tetanus toxoid-specific T cell clones after antigenic stimulation. Peripheral blood DC from aged individuals may thus still function as powerful APC. They may represent useful tools for immunotherapy in the aged.
MeSH Terms
- Adolescent
- Adult
- Aged
- Aging
- Antigen Presentation
- Biomarkers
- Cell Division
- Dendritic Cells
- Humans
Protein phosphorylation is considered an early cellular mechanism of signal transduction by surface immunoglobulins (sIg) and other receptors of B cells. Using intact human peripheral blood B cells of young subjects labeled with orthophosphate, increased phosphorylation levels of serine/threonine and tyrosine substrates were demonstrated on indicator phosphoproteins corresponding to the CD20 isoforms and microtubule-associated protein 2 kinase after cross-linking sIg and costimulation with phorbol diesters. By contrast, stimulated B cells from certain elderly subjects displayed substantial alterations in the phosphorylation patterns of serine/threonine or tyrosine indicator phosphoproteins. Also, age-related impairments in sIg stimulated mobilization of cytosolic protein kinase C (PKC) enzymatic activity and in cytosolic calcium [Ca2 ]i responses of B cells were observed with the altered phosphorylation reactions. Comparison of the substrate phosphorylation profiles to the proliferative responses of stimulated B cells from individual elderly subjects suggested a model of signal transduction in which differing stimuli have different dependencies on phosphorylation reactions. Diminished proliferative responses after sIg ligation coincided with decreased phosphorylations of either tyrosine or serine/threonine indicator substrates. However, the decreased proliferative responses of B cells from elderly subjects with substantial reductions of tyrosine phosphorylation after sIg ligation were enhanced by the direct stimulation of serine/threonine kinase activity with phorbol diesters or CD40 ligation. Experiments with kinase inhibitors evaluated the relative dependency of different B cell stimuli on tyrosine and serine/threonine phosphorylation reactions. The proliferative responses of normal B cells to sIg ligation were quite sensitive to the tyrosine kinase inhibitor genistein whereas those observed following costimulations with phorbol diesters or CD40 ligation were more resistant. However, treatment of B cells with H7, an inhibitor of PKC activity, led to a more uniform reduction of B-cell responses after different stimuli. Results from RNase protection assays of c-myc expression also suggested that different B-cell stimuli might utilize distinct intracellular signaling pathways. Both the type of stimuli and mode of sIg ligation were important in determining the stimulated levels of c-myc mRNA expression. Thus, the current findings suggest that age-related defects are present in human B cell signaling pathways as reflected by tyrosine and serine/threonine phosphorylation reactions. Also, these age-related defects can coexist with altered mobilization of PKC enzymatic activity and with alterations in [Ca2 ]i and proliferative responses.
MeSH Terms
- Aging
- Amino Acids
- B-Lymphocytes
- Calcium
- Cell Division
- Cells, Cultured
- Cytosol
- Humans
- Phosphorylation
- Protein Kinase C
- Protein-Tyrosine Kinases
- Ribonucleases
- Serine
- Signal Transduction
- Threonine
- Tyrosine
Age-related reductions in the DNA replication of human peripheral blood B cells have been reported after stimulation by cross-linking surface immunoglobulins (sIg) with the polyclonal activator Staphylococcus aureus Cowan I (SAC). However, little is known about the mechanisms of these age-related impairments. To examine whether these impairments represented defects unique to sIg mediated signalling, B cells from elderly humans were stimulated with SAC, immobilized anti-IgM and with monoclonal antibodies (mAbs) specific for B cell CD20 and CD40 determinants. Regardless of the stimuli or combinations of stimuli, the proliferative responses of B cells from elderly subjects remained 50% or less of the values observed for B cells from young subjects. Also, the failure to fully restore the age-related impairments of B cells could not be attributed to an absolute lack of potentially reactive cells. Supplementation of anti-IgM stimulated B cells from elderly subjects with IL-2, IL-4 or B cell growth factor (BCGF) revealed that BCGF was able to improve the reduced responses to levels approximating B cells of young subjects. The age-related defects were not restricted to B cell DNA replication because reductions in G1 progression of stimulated B cells from elderly subjects were directly demonstrated by decreased [3H]uridine incorporation into de novo RNA synthesis. However, the age-related impairments in RNA synthesis were less severe than those in DNA replication consistent with progressively greater reductions in the abilities of B cells to traverse the entire cell cycle. Other results showed that the reduced DNA replication of B cells from elderly subjects to immobilized anti-IgM with and without IL-2 did not represent a premature exit of B cells from DNA replication and accelerated maturation into antibody producing cells. Thus, these studies demonstrate that age-related impairments exist in activation signals mediated by several types of human B cell determinants and that abnormalities can be detected during pre-S phase events.
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Aging
- Antigens, CD
- Antigens, CD20
- Antigens, Differentiation, B-Lymphocyte
- B-Lymphocytes
- CD40 Antigens
- Cell Cycle
- DNA Replication
- Humans
- In Vitro Techniques
- Lymphocyte Activation
- Middle Aged
- RNA
- Receptors, Antigen, B-Cell
- Signal Transduction