Premature CD4+ T Cells Senescence Induced by Chronic Infection in Patients with Acute Coronary Syndrome.
ABSTRACT: Acquired immune responses mediated by CD4+ T cells contribute to the initiation and progression of acute coronary syndrome (ACS). ACS patients show acquired immune system abnormalities that resemble the characteristics of autoimmune dysfunction described in the elderly. This study aimed to investigate the role of premature CD4+ T cells senescence in ACS and the underlying mechanism. We compared the immunological status of 25 ACS patients, 15 young healthy individuals (C1), and 20 elderly individuals with absence of ACS (C2). The percentages of CD4+ T lymphocyte subsets (including naïve, regulatory, memory and effector T cells) in peripheral blood were analyzed. In ACS patients, a significant expansion of CD4+CD28null effector T cells and a decline of CD4+CD25+CD62L+Treg cells were observed. In addition, patients with ACS showed an accelerated loss of CD4+CD45RA+CD62L+ naïve T cells and a compensatory increase in the number of CD4+CD45RO+ memory T cells. ACS patients demonstrated no significant difference in frequency of T cell receptor excision circles (TRECs) compared to age-matched healthy volunteers. The expression of p16Ink4a was increased while CD62L was decreased in CD4+CD28null T cells of ACS patients. Compared to healthy donors, ACS patients demonstrated the lowest telomerase activity in both CD4+CD28+and CD4+CD28null T cells. The serum levels of C-reactive protein, Cytomegalovirus IgG, Helicobactor pylori IgG and Chlamydia pneumonia IgG were significantly higher in ACS patients. The results suggested that the percentage of CD4+ T cell subpopulations correlated with chronic infection, which contributes to immunosenescence. In conclusion, chronic infection induced senescence of premature CD4+T cells, which may be responsible for the development of ACS.
Project description:Peripheral inflammation acts synergistically with hyperammonemia in inducing neurological alterations in cirrhotic patients with minimal hepatic encephalopathy (MHE). We hypothesized that appearance of MHE would be associated to some specific qualitative change in peripheral inflammation. The aim of this work was to characterize the changes in peripheral inflammation associated to appearance of MHE. We analyzed it by immunophenotyping and cytokine profile analysis, in cirrhotic patients without or with MHE and controls. The main alterations associated specifically with MHE are: 1) increased activation of all subtypes of CD4<sup>+</sup> T-lymphocytes, with the increased expression of CD69; 2) increased amount of CD4<sup>+</sup>CD28<sup>-</sup> T lymphocytes, associated with increased levels of CX3CL1 and of IL-15; 3) increased differentiation of CD4<sup>+</sup> T lymphocytes to Th follicular and Th22; 4) increased activation of B lymphocytes and serum IgG. This study has identified some specific alterations of the immune system associated with appearance of the neurological alterations in MHE patients.
Project description:Clinical response rates after adoptive cell therapy (ACT) are highly correlated with <i>in vivo</i> persistence of the infused T cells. However, antigen-specific T cells found in tumor sites are often well-differentiated effector cells with limited persistence. Central memory CD8<sup>+</sup> T cells, capable of self-renewal, represent desirable ACT products. We report here that exposure to a histone deacetylase inhibitor (HDACi) and IL21 could reprogram differentiated human CD8<sup>+</sup> T cells into central memory-like T cells. Dedifferentiation of CD8<sup>+</sup> T cells was initiated by increased H3 acetylation and chromatin accessibility at the <i>CD28</i> promoter region. This led to IL21-mediated pSTAT3 binding to the <i>CD28</i> region, and subsequent upregulation of surface CD28 and CD62L (markers of central memory T cells). The reprogrammed cells exhibited enhanced proliferation in response to both IL2 and IL15, and a stable memory-associated transcriptional signature (increased <i>Lef1</i> and <i>Tcf7</i>). Our findings support the application of IL21 and HDACi for the <i>in vitro</i> generation of highly persistent T-cell populations that can augment the efficacy of adoptively transferred T cells.
Project description:Mechanisms driving acute graft-versus-host disease (aGVHD) onset in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) are still poorly understood. To provide a detailed characterization of tissue-infiltrating T lymphocytes (TL) and search for eventual site-specific specificities, we developed a xenogeneic model of aGVHD in immunodeficient mice. Phenotypic characterization of xenoreactive T lymphocytes (TL) in diseased mice disclosed a massive infiltration of GVHD target organs by an original CD4<sup>+</sup>CD8<sup>+</sup> TL subset. Immunophenotypic and transcriptional profiling shows that CD4<sup>+</sup>CD8<sup>+</sup> TL comprise a major PD1<sup>+</sup>CD62L<sup>-/+</sup> transitional memory subset (>60%) characterized by low level expression of cytotoxicity-related transcripts. CD4<sup>+</sup>CD8<sup>+</sup> TL produce high IL-10 and IL-13 levels, and low IL-2 and IFN-?, suggestive of regulatory function. In vivo tracking of genetically labeled CD4<sup>+</sup> or CD8<sup>+</sup> TL subsequently found that CD4<sup>+</sup>CD8<sup>+</sup> TL mainly originate from chronically activated cytotoxic TL (CTL). On the other hand, phenotypic profiling of CD3<sup>+</sup> TL from blood, duodenum or rectal mucosa in a cohort of allo-HSCT patients failed to disclose abnormal expansion of CD4<sup>+</sup>CD8<sup>+</sup> TL independent of aGVHD development. Collectively, our results show that acquisition of surface CD4 by xenoreactive CD8<sup>+</sup> CTL is associated with functional diversion toward a regulatory phenotype, but rule out a central role of this subset in the pathogenesis of aGVHD in allo-HSCT patients.
Project description:Low-grade systemic inflammation associated to obesity leads to cardiovascular complications, caused partly by infiltration of adipose and vascular tissue by effector T cells. The signals leading to T cell differentiation and tissue infiltration during obesity are poorly understood. We tested whether saturated fatty acid-induced metabolic stress affects differentiation and trafficking patterns of CD4<sup>+</sup> T cells. Memory CD4<sup>+</sup> T cells primed in high-fat diet-fed donors preferentially migrated to non-lymphoid, inflammatory sites, independent of the metabolic status of the hosts. This was due to biased CD4<sup>+</sup> T cell differentiation into CD44<sup>hi</sup>-CCR7<sup>lo</sup>-CD62L<sup>lo</sup>-CXCR3<sup>+</sup>-LFA1<sup>+</sup> effector memory-like T cells upon priming in high-fat diet-fed animals. Similar phenotype was observed in obese subjects in a cohort of free-living people. This developmental bias was independent of any crosstalk between CD4<sup>+</sup> T cells and dendritic cells and was mediated via direct exposure of CD4<sup>+</sup> T cells to palmitate, leading to increased activation of a PI3K p110?-Akt-dependent pathway upon priming.
Project description:Stimulation with antibodies to CD3 and CD28 coimmobilized on beads can be used to significantly expand T cells ex vivo. With CD4 T cells from HIV-infected patients, this expansion usually is accompanied by complete suppression of viral replication, presumed to be caused by down-regulation of the viral coreceptor CCR5 and up-regulation of CCR5 ligands. Here we show that this suppression occurs in total CD4 T cells acutely infected with R5 HIV, but not in purified CD62L(-) memory CD4 T cells. The lack of complete suppression in these memory cells, typically comprising 10-40% of total CD4 T cells, occurs despite high levels of CCR5 ligand secretion and down-regulation of CCR5. Significantly, adding back naive or CD62L(+) memory CD4 T cells inhibits the viral replication in the CD62L(-) cells, with the naive cells capable of completely repressing the virus. Although this inhibition was previously thought to be specific to bead-bound anti-CD3/CD28 stimulation, we show that the same suppression is obtained with sufficiently strong anti-CD3/B7.1 stimulation. Our results show that inhibitory mechanisms, expressed predominantly by strongly stimulated naive CD4 T cells and mediated independently of CCR5-binding chemokines, play a role in the inhibition of R5 HIV replication in CD4 T cells upon CD28 costimulation.
Project description:After repeated antigen exposure, both memory and terminally differentiated cells can be generated within CD8<sup>+</sup> T cells. Although, during their differentiation, activated CD8<sup>+</sup> T cells may first lose CD28, and CD28<sup>-</sup> cells may eventually express CD57 as a subsequent step, a population of CD28<sup>+</sup> CD57<sup>+</sup> (DP) CD8<sup>+</sup> T cells can be identified in the peripheral blood. How this population is distinct from CD28<sup>-</sup> CD57<sup>-</sup> (DN) CD8<sup>+</sup> T cells, and from the better characterized non-activated/early-activated CD28<sup>+</sup> CD57<sup>-</sup> and senescent-like CD28<sup>-</sup> CD57<sup>+</sup> CD8<sup>+</sup> T cell subsets is currently unknown. Here, RNA expression of the four CD8<sup>+</sup> T cell subsets isolated from human PBMCs was analyzed using microarrays. DN cells were more similar to "early" highly differentiated cells, with decreased TNF and IFN-? production, impaired DNA damage response and apoptosis. Conversely, increased apoptosis and expression of cytokines, co-inhibitory, and chemokine receptors were found in DP cells. Higher levels of DP CD8<sup>+</sup> T cells were observed 7 days after Hepatitis B vaccination, and decreased levels of DP cells were found in rheumatoid arthritis patients. More DP and DN CD8<sup>+</sup> T cells were present in the bone marrow, in comparison with PBMCs. In summary, our results indicate that DP and DN cells are distinct CD8<sup>+</sup> T cell subsets displaying defined properties.
Project description:Superoxide dismutase 3 (SOD3), a well-known antioxidant has been shown to possess immunomodulatory properties through inhibition of T cell differentiation. However, the underlying inhibitory mechanism of SOD3 on T cell differentiation is not well understood. In this study, we investigated the effect of SOD3 on anti-CD3/CD28- or phorbol myristate acetate (PMA) and ionomycin (ION)-mediated activation of mouse naive CD4<sup>+</sup> T cells. Our data showed that SOD3 suppressed the expression of activation-induced surface receptor proteins such as CD25, and CD69, and cytokines production. Similarly, SOD3 was found to reduce CD4<sup>+</sup>T cells proliferation and suppress the activation of downstream pathways such as ERK, p38, and NF-?B. Moreover, naïve CD4<sup>+</sup>T cells isolated from global SOD3 knock-out mice showed higher expression of CD25, CD69, and CD71, IL-2 production, proliferation, and downstream signals compared to wild-type CD4<sup>+</sup>T cells. Whereas, the use of DETCA, a known inhibitor of SOD3 activity, found to nullify the inhibitory effect of SOD3 on CD4<sup>+</sup>T cell activation of both SOD3 KO and wild-type mice. Furthermore, the expression of surface receptor proteins, IL-2 production, and downstream signals were also reduced in Th2 and Th17 differentiated cells upon SOD3 treatment. Overall, our data showed that SOD3 can attenuate CD4<sup>+</sup>T cell activation through modulation of the downstream signalings and restrict CD4<sup>+</sup>T cell differentiation. Therefore, SOD3 can be a promising therapeutic for T cell-mediated disorders.
Project description:<label>BACKGROUND</label>We examined the effect of cytomegalovirus (CMV) co-infection and viremia on reconstitution of selected CD4+ and CD8+ T-cell subsets in perinatally HIV-infected (PHIV+) children ? 1-year old who participated in a partially randomized, open-label, 96-week combination antiretroviral therapy (cART)-algorithm study.<label>METHODS</label>Participants were categorized as CMV-naïve, CMV-positive (CMV+) viremic, and CMV+ aviremic, based on blood, urine, or throat culture, CMV IgG and DNA polymerase chain reaction measured at baseline. At weeks 0, 12, 20 and 40, T-cell subsets including naïve (CD62L+CD45RA+; CD95-CD28+), activated (CD38+HLA-DR+) and terminally differentiated (CD62L-CD45RA+; CD95+CD28-) CD4+ and CD8+ T-cells were measured by flow cytometry.<label>RESULTS</label>Of the 107 participants included in the analysis, 14% were CMV+ viremic; 49% CMV+ aviremic; 37% CMV-naïve. In longitudinal adjusted models, compared with CMV+ status, baseline CMV-naïve status was significantly associated with faster recovery of CD8+CD62L+CD45RA+% and CD8+CD95-CD28+% and faster decrease of CD8+CD95+CD28-%, independent of HIV VL response to treatment, cART regimen and baseline CD4%. Surprisingly, CMV status did not have a significant impact on longitudinal trends in CD8+CD38+HLA-DR+%. CMV status did not have a significant impact on any CD4+ T-cell subsets.<label>CONCLUSIONS</label>In this cohort of PHIV+ children, the normalization of naïve and terminally differentiated CD8+ T-cell subsets in response to cART was detrimentally affected by the presence of CMV co-infection. These findings may have implications for adjunctive treatment strategies targeting CMV co-infection in PHIV+ children, especially those that are now adults or reaching young adulthood and may have accelerated immunologic aging, increased opportunistic infections and aging diseases of the immune system.
Project description:<h4>Purpose</h4>Mutations in the isocitrate dehydrogenase-1 gene (IDH1) occur at high frequency in grade II-III gliomas (LGGs). IDH1 mutations are somatic, missense and heterozygous affecting codon 132 in the catalytic pocket of the enzyme. In LGG, most mutations (90%) result in an arginine to histidine substitution (IDH1<sup>R132H</sup>) providing a neo-epitope that is expressed in all tumor cells. To assess the immunogenic nature of this epitope, and its potential use to develop T cell treatments, we measured IDH1<sup>R132H</sup>-specific B and T cell reactivity in blood and tumor tissue of LGG patients.<h4>Methods</h4>Sera from IDH1<sup>R132H</sup>-mutated LGG patients (n?=?27) were assayed for the presence of a neo-specific antibody response using ELISA. In addition, PBMCs (n?=?36) and tumor-infiltrating lymphocytes (TILs, n?=?10) were measured for T cell activation markers and IFN-? production by flow cytometry and ELISA. In some assays, frequencies of CD4 T cells specific for mutated peptide presented by HLA-DR were enriched prior to T cell monitoring assays.<h4>Results</h4>Despite high sensitivity of our assay, we failed to detect IDH1<sup>R132H</sup>-specific IgG in sera of LGG patients. Similarly, we did not observe CD4 T cell reactivity towards IDH1<sup>R132H</sup> in blood, neither did we observe such reactivity following pre-enrichment of frequencies of IDH1<sup>R132H</sup>-specific CD4 T cells. Finally, we did not detect IDH1<sup>R132H</sup>-specific CD4 T cells among TILs.<h4>Conclusions</h4>The absence of both humoral and cellular responses in blood and tumors of LGG patients indicates that IDH1<sup>R132H</sup> is not sufficiently immunogenic and devaluates its further therapeutic exploitation, at least in the majority of LGG patients.
Project description:The immune system plays a central role in cancer development, showing both anti-tumor and pro-tumor activities depending on the immune cell subsets and the disease context. While CD8 T cells are associated with a favorable outcome in most cancers, only T helper type 1 (Th1) CD4 T cells play a protective role, in contrast to Th2 CD4 T cells. Double positive (DP) CD4<sup>+</sup>CD8<sup>+</sup> T cells remain understudied, although they were already described in human cancers, with conflicting data regarding their role. Here, we quantified and phenotypically/functionally characterized DP T cells in blood from urological cancer patients. We analyzed blood leukocytes of 24 healthy donors (HD) and 114 patients with urological cancers, including bladder (<i>n</i> = 54), prostate (<i>n</i> = 31), and kidney (<i>n</i> = 29) cancer patients using 10-color flow cytometry. As compared to HD, levels of circulating DP T cells were elevated in all urological cancer patients, which could be attributed to increased frequencies of both CD4<sup>high</sup>CD8<sup>low</sup> and CD4<sup>+</sup>CD8<sup>high</sup> DP T-cell subsets. Of note, most CD4<sup>high</sup>CD8<sup>low</sup> DP T cells show a CD8?? phenotype, whereas CD4<sup>+</sup>CD8<sup>high</sup> cells express both CD8? and CD8? subunits. Functional properties were investigated using <i>ex-vivo</i> generated DP T-cell clones. DP T cells from patients were skewed toward an effector memory phenotype, along with enhanced Th2 cytokine production. Interestingly, both CD8?? and CD8?? DP T cells were able to trigger Th2 polarization of naïve CD4 T cells, while restraining Th1 induction. Thus, these data highlight a previously unrecognized immunoregulatory mechanism involving DP CD4<sup>+</sup>CD8<sup>+</sup> T cells in urological cancers.