Significantly skewed memory CD8+ T cell subsets in HIV-1 infected infants during the first year of life.
ABSTRACT: HIV-1 infection causes a severe T cell compromise; however, little is known about changes in naive, memory, effector and senescent T cell subsets during the first year of life. T cell subsets were studied over the first year of life in blood from 3 infant cohorts: untreated HIV-infected, HIV-exposed but uninfected, and HIV-unexposed. In HIV-infected infants, the frequency of CCR7(+)CD45RA(+) naive CD8(+) T cells was significantly decreased, while the frequency of CCR7(-)CD45RA(-) effector memory CD8(+) T cells was increased, compared with the control cohorts. A larger population of CD8(+) T cells in HIV-infected infants displayed a phenotype consistent with senescence. Differences in CD4(+) T cell subset frequencies were less pronounced, and no significant differences were observed between exposed and unexposed HIV-uninfected infants. We concluded that the proportion of naive, memory, effector and senescent CD8(+) T cells during the first year of life is significantly altered by HIV-1 infection.
Project description:CD8(+) T cells play important roles in anti-tumor immunity but distribution profile or functional characteristics of effector memory subsets during tumor progression are unclear. We found that, in oral squamous carcinoma patients, circulating CD8(+) T cell pools skewed toward effector memory subsets with the distribution frequency of CCR7(-)CD45RA(-)CD8(+) T cells and CCR7(-) CD45RA(+)CD8(+) T cells negatively correlated with each other. A significantly higher frequency of CD127(lo) CCR7(-)CD45RA(-)CD8(+) T cells or CCR7(-)CD45RA(+)CD8(+) T cells among total CD8(+) T cells was found in peripheral blood or tumor infiltrating lymphocytes, but not in regional lymph nodes. The CD127(hi) CCR7(-)CD45RA(-)CD8(+) T cells or CCR7(-)CD45RA(+)CD8(+) T cells maintained significantly higher IFN-?, IL-2 productivity and ex vivo proliferative capacity, while the CD127(lo) CCR7(-)CD45RA(-)CD8(+) T cells or CCR7(-)CD45RA(+)CD8(+) T cells exhibited higher granzyme B productivity and susceptibility to activation induced cell death. A higher ratio of CCR7(-)CD45RA(+)CD8(+) T cells to CCR7(-)CD45RA(-)CD8(+) T cells was associated with advanced cancer staging and poor differentiation of tumor cells. Therefore, the CD127(lo) CCR7(-)CD45RA(-)CD8(+) T cells and CCR7(-)CD45RA(+)CD8(+) T cells are functionally similar CD8(+) T cell subsets which exhibit late differentiated effector phenotypes and the shift of peripheral CD8(+) effector memory balance toward CCR7(-)CD45RA(+)CD8(+) T cells is associated with OSCC progression.
Project description:The aim was to assess miRNA expression in 3 human ex-vivo CD8+ T cell subsets which span from antigen inexperienced cells (NaM-CM-/ve) to early memory cells (central memory, Tcm) and later stage memory cells (effector memory, Tem) CD8+ T cells were sorted on a FACS Aria II machine. N = naM-CM-/ve = CD8+, CCR7+, CD45RA+, CD45RO-, Tcm = central memory = CD8+, CCR7+, CD45RA-, CD45RO-,Tem= effector memory = CD8+, CCR7-, CD45RA-, CD45RO+ PBMC were isolated from 3 healthy human donors and sorted by FACS into 3 CD8+ T cell subsets. Total RNA was purified using the miRVANA kit (Ambion)
Project description:Humanized mice are expected to be useful as small animal models for in vivo studies on the pathogenesis of infectious diseases. However, it is well known that human CD8(+) T cells cannot differentiate into effector cells in immunodeficient mice transplanted with only human CD34(+) hematopoietic stem cells (HSCs), because human T cells are not educated by HLA in the mouse thymus. We here established HLA-B*51:01 transgenic humanized mice by transplanting human CD34(+) HSCs into HLA-B*51:01 transgenic NOD/SCID/Jak3(-/-) mice (hNOK/B51Tg mice) and investigated whether human effector CD8(+) T cells would be elicited in the mice or in those infected with HIV-1 NL4-3. There were no differences in the frequency of late effector memory and effector subsets (CD27(low)CD28(-)CD45RA(+/-)CCR7(-) and CD27(-)CD28(-)CD45RA(+/-)CCR7(-), respectively) among human CD8(+) T cells and in that of human CD8(+) T cells expressing CX3CR1 and/or CXCR1 between hNOK/B51Tg and hNOK mice. In contrast, the frequency of late effector memory and effector CD8(+) T cell subsets and of those expressing CX3CR1 and/or CXCR1 was significantly higher in HIV-1-infected hNOK/B51Tg mice than in uninfected ones, whereas there was no difference in that of these subsets between HIV-1-infected and uninfected hNOK mice. These results suggest that hNOK/B51Tg mice had CD8(+) T cells that were capable of differentiating into effector T cells after viral antigen stimulation and had a greater ability to elicit effector CD8(+) T cells than hNOK ones.
Project description:The aim was to assess miRNA expression in 3 human ex-vivo CD8+ T cell subsets which span from antigen inexperienced cells (Naïve) to early memory cells (central memory, Tcm) and later stage memory cells (effector memory, Tem) CD8+ T cells were sorted on a FACS Aria II machine. N = naïve = CD8+, CCR7+, CD45RA+, CD45RO-, Tcm = central memory = CD8+, CCR7+, CD45RA-, CD45RO-,Tem= effector memory = CD8+, CCR7-, CD45RA-, CD45RO+ PBMC were isolated from 3 healthy human donors and sorted by FACS into 3 CD8+ T cell subsets. Total RNA was purified using the miRVANA kit (Ambion)
Project description:Flexibility of the HIV-specific T-cell receptor repertoire is a hallmark of HIV-1 infection. Altered differentiation of HIV-specific CD45RO(+)/CCR7(-) (TemRO) CD8(+) effector-memory T cells into CD45RA(+)/CCR7(-) (TemRA) CD8(+) effector-memory T cells as well as increased expression of the senescence marker CD57 has been frequently observed HIV-1 infection, but the structural relationship between clonal expansion and T-cell differentiation has not been defined. In this study, we demonstrate that HIV-specific clonotypes have differing degrees of TemRA differentiation but always maintain a significant proportion of TemRO-phenotype cells. These data indicate that structural constraints of the TCR/peptide major histocompatibility complex interaction play a central role in the TemRA differentiation of HIV-specific CD8(+) T cells in chronic HIV-1 infection. Clonotypes with a predominantly TemRA phenotype had a substantial fraction of cells without expression of CD57; and in contrast to the high clonotypic variability of TemRA differentiation, expression of CD57 was highly correlated among T-cell clonotypes within epitope-specific responses, indicating TCR-independent expression of CD57 in vivo. Our data highlight the importance of the structural composition of the TCR repertoire for the effector-memory differentiation of the immune response in chronic viral infections and suggest that TCR-dependent and -independent homeostasis shapes the pathogen-specific effector-memory repertoire in vivo.
Project description:T cell senescence is thought to contribute to immune function decline, but the pathways that mediate senescence in these cells are not clear. Here, we evaluated T cell populations from healthy volunteers and determined that human CD8+ effector memory T cells that reexpress the naive T cell marker CD45RA have many characteristics of cellular senescence, including decreased proliferation, defective mitochondrial function, and elevated levels of both ROS and p38 MAPK. Despite their apparent senescent state, we determined that these cells secreted high levels of both TNF-? and IFN-? and showed potent cytotoxic activity. We found that the senescent CD45RA-expressing population engaged anaerobic glycolysis to generate energy for effector functions. Furthermore, inhibition of p38 MAPK signaling in senescent CD8+ T cells increased their proliferation, telomerase activity, mitochondrial biogenesis, and fitness; however, the extra energy required for these processes did not arise from increased glucose uptake or oxidative phosphorylation. Instead, p38 MAPK blockade in these senescent cells induced an increase in autophagy through enhanced interactions between p38 interacting protein (p38IP) and autophagy protein 9 (ATG9) in an mTOR-independent manner. Together, our findings describe fundamental metabolic requirements of senescent primary human CD8+ T cells and demonstrate that p38 MAPK blockade reverses senescence via an mTOR-independent pathway.
Project description:Accumulating evidence demonstrates that CD8+ T cells contribute to protection from severe dengue virus (DENV) disease and vaccine efficacy. Nevertheless, molecular programs associated with DENV-specific CD8+ T cell subsets have not been defined. Here, we studied the transcriptomic profiles of human DENV-specific CD8+ T cells isolated after stimulation with DENV epitopes from donors who had been infected with DENV multiple times and would therefore be expected to have significant levels of adaptive immunity. We found that DENV-specific CD8+ T cells mainly consisted of effector memory subsets, namely CD45RA-CCR7- effector memory (Tem) and CD45RA+CCR7- effector memory re-expressing CD45RA (Temra) cells, which enacted specific gene expression profiles upon stimulation with cognate antigens. DENV-specific CD8+ T cell subsets in general, and Temra cells in particular, were fully activated and polyfunctional, yet associated with relatively narrow transcriptional responses. Furthermore, we found that DENV-specific CD8+ Tem and Temra cells showed some unique T cell receptor features in terms of overlap and variable (V) gene usage. This study provides a transcriptomic definition of DENV-specific activated human CD8+ T cell subsets and defines a benchmark profile that vaccine-specific responses could aim to reproduce.
Project description:The live yellow fever vaccine (YF-17D) offers a unique opportunity to study memory CD8(+) T cell differentiation in humans following an acute viral infection. We have performed a comprehensive analysis of the virus-specific CD8(+) T cell response using overlapping peptides spanning the entire viral genome. Our results showed that the YF-17D vaccine induces a broad CD8(+) T cell response targeting several epitopes within each viral protein. We identified a dominant HLA-A2-restricted epitope in the NS4B protein and used tetramers specific for this epitope to track the CD8(+) T cell response over a 2 year period. This longitudinal analysis showed the following. 1) Memory CD8(+) T cells appear to pass through an effector phase and then gradually down-regulate expression of activation markers and effector molecules. 2) This effector phase was characterized by down-regulation of CD127, Bcl-2, CCR7, and CD45RA and was followed by a substantial contraction resulting in a pool of memory T cells that re-expressed CD127, Bcl-2, and CD45RA. 3) These memory cells were polyfunctional in terms of degranulation and production of the cytokines IFN-gamma, TNF-alpha, IL-2, and MIP-1beta. 4) The YF-17D-specific memory CD8(+) T cells had a phenotype (CCR7(-)CD45RA(+)) that is typically associated with terminally differentiated cells with limited proliferative capacity (T(EMRA)). However, these cells exhibited robust proliferative potential showing that expression of CD45RA may not always associate with terminal differentiation and, in fact, may be an indicator of highly functional memory CD8(+) T cells generated after acute viral infections.
Project description:The performance of host blood-based biomarkers for tuberculosis (TB) in HIV-infected patients on antiretroviral therapy (ART) has not been fully assessed. We evaluated the immune phenotype and functionality of antigen-specific T-cell responses in HIV positive (+) participants with TB (n = 12) compared to HIV negative (-) participants with either TB (n = 9) or latent TB infection (LTBI) (n = 9). We show that the cytokine profile of Mtb-specific CD4+ T-cells in participants with TB, regardless of HIV status, was predominantly single IFN-? or dual IFN-?/ TNF?. Whilst ESAT-6/CFP-10 responding T-cells were predominantly of an effector memory (CD27-CD45RA-CCR7-) profile, HIV-specific T-cells were mainly of a central (CD27+CD45RA-CCR7+) and transitional memory (CD27+CD45RA+/-CCR7-) phenotype on both CD4+ and CD8+ T-cells. Using receiving operating characteristic (ROC) curve analysis, co-expression of CD38 and HLA-DR on ESAT-6/CFP-10 responding total cytokine-producing CD4+ T-cells had a high sensitivity for discriminating HIV+TB (100%, 95% CI 70-100) and HIV-TB (100%, 95% CI 70-100) from latent TB with high specificity (100%, 95% CI 68-100 for HIV-TB) at a cut-off value of 5% and 13%, respectively. TB treatment reduced the proportion of Mtb-specific total cytokine+CD38+HLA-DR+ CD4+ T-cells only in HIV-TB (p = 0.001). Our results suggest that co-expression of CD38 and HLA-DR on Mtb-specific CD4+ T-cells could serve as a TB diagnosis tool regardless of HIV status.
Project description:Regulatory T cells (Tregs) are major components of tumor-infiltrating immune cells with potent immunosuppressive properties in gastric cancer (GC) microenvironment. However, different subsets of the Tregs and their relevance to GC are unknown. Here, we found that patients with GC showed a significantly higher Tregs infiltration in tumors, and CD45RA-CCR7- Treg subset constituted most tumor-infiltrating Tregs. Tumor-infiltrating CD45RA-CCR7- Treg subset with an effector/memory phenotype accumulated in tumors and expressed low level of HLA-DR. Gastric tumor-derived TNF-? induced CD45RA-CCR7- Treg subset with similar phenotype to their status in tumors and inhibited their HLA-DR expression via activating STAT3 phosphorylation. These tumor-associated CD45RA-CCR7- Treg subset exerted superior immunosuppressive properties to effectively suppress CD8+ T cells' anti-tumor function including CD8+ T-cell IFN-? and granzyme B (GrB) production as well as CD8+ T-cell proliferation in vitro, and also contributed to the growth and progression of human gastric tumors in vivo, via IL-10 secretion and cell-cell contact mechanisms. Moreover, increased tumor-infiltrating CD45RA-CCR7- Treg subset as well as higher intratumoral CD45RA-CCR7- Treg/CD8+ T-cell ratio was associated with advanced disease progression and reduced GC patient survival. This study therefore identifies a novel immunosuppressive pathway involving CD45RA-CCR7- Treg subset development within the GC microenvironment. Efforts to inhibit this pathway may therefore prove a valuable strategy to prevent, and to treat this immune suppressive of GC.