Project description:We demonstrate that CXCR5+CD8+ T cells are a distinct human T-cell subset that homes to follicles and exerts strong antitumor activity compared with CXCR5-CD8+ T cells. Importantly, this subset is associated with improved outcome in follicular lymphoma patients.
Project description:In mice chronically infected with lymphocytic choriomeningitis virus (LCMV), we defined a subset of exhausted CD8+ T cells abundantly expressing chemokine receptor CXCR5. These CXCR5+ CD8+ T cells were preferentially localized in B cell follicles, expressing less inhibitory receptors while exhibiting more potent cytolytic activity compared to the CXCR5- subset. Furthermore, we identified Id2-E2A axis as the regulator for the generation of this subset. In line with mouse LCMV chronic infection, we also identified a CXCR5+ CD8+ T cell subset in human HIV patients, which negatively correlated with viral load. Moreover, when adoptively transferred to chronically infected recipients, CXCR5+ subset showed greater therapeutic potential than CXCR5- subset.
Project description:The vast majority of currently licensed human vaccines work on the basis of long-term protective antibody responses. Generation of long term humoral immunity is a complex process predominantly dependent on germinal centers and CD4 T cell help to B cells. Follicular helper T cells (Tfh) are the specialized CD4 T cells for B cell help. However, whether such cells develop memory in humans and can be tracked in human blood has been enigmatic. We identified a subpopulation of blood CXCR5+ PD-1+CXCR3- resting CD4 T cells that are most related to Tfh cells of lymphoid tissue by gene expression profile and phenotype. Functional analysis showed that these memory Tfh cells were specialized for helping B cells. Moreover, these cells correlate with a clinically important outcome: development of potent neutralizing antibodies against HIV in HIV+ individuals. CD4 T cells were enriched from fresh blood of 5 normal donors by magnetic beads negative selection. Following enrichment, CD14-CD16-CD19-CD8-CD4+CD45RA- cells from each donor were FACS sorted into the following 5 populations: CXCR5-, CXCR5+PD1+CXCR3-, CXCR5+PD1+CXCR3+, CXCR5+PD1-CXCR3-, and CXCR5+PD1-CXCR3+. The gene expression profile of each cell population was determined.
Project description:In response to infection, antigen-specific CD8+ T cells are primed in the T cell zone of secondary lymphoid organs and differentiate into cytotoxic effector T (TC) cells. Concurrently, CD4+ T cells differentiate into follicular helper T (TFH) cells that localize to B cell follicles and promote protective antibody responses. During unresolved infections, however, some viruses including human immunodeficiency virus (HIV) or Epsteinâ??Barr virus (EBV) escape immune control and persist in TFH cells and B cells, respectively. Exclusion of Tc cells from B cell follicles is thought to be a major mechanism of immune evasion. New strategies are therefore needed to eradicate infected cells in follicles for a permanent cure. Using mouse infection models and human samples, we here identify a specialized group of TC cells expressing the chemokine receptor CXCR5 that can selectively enter B cell follicles and eradicate infected TFH and B cells. We demonstrate that differentiation of these cells, which we term follicular cytotoxic T (TFC) cells, requires the transcription factors Bcl6, E2A and Tcf1, whereas the transcriptional regulators Blimp1, Id3 and Id2 inhibit their development. We demonstrate that Blimp1 and E2A directly regulate Cxcr5 expression, and together with Bcl6 and Tcf1 form a transcriptional circuit that guides the TFC differentiation. The identification of a follicular subset of TC cells has far reaching implications for developing better strategies for the control of infections that target B cells and TFH cells and for the eradication of B cell derived malignancies. There is no associated input. The E2A Bio-ChIP-seq was performed with total thymocytes from Tcf3Bio/Bio Rosa26BirA/BirA mice
Project description:In response to infection, antigen-specific CD8+ T cells are primed in the T cell zone of secondary lymphoid organs and differentiate into cytotoxic effector T (TC) cells. Concurrently, CD4+ T cells differentiate into follicular helper T (TFH) cells that localize to B cell follicles and promote protective antibody responses. During unresolved infections, however, some viruses including human immunodeficiency virus (HIV) or Epstein–Barr virus (EBV) escape immune control and persist in TFH cells and B cells, respectively. Exclusion of Tc cells from B cell follicles is thought to be a major mechanism of immune evasion. New strategies are therefore needed to eradicate infected cells in follicles for a permanent cure. Using mouse infection models and human samples, we here identify a specialized group of TC cells expressing the chemokine receptor CXCR5 that can selectively enter B cell follicles and eradicate infected TFH and B cells. We demonstrate that differentiation of these cells, which we term follicular cytotoxic T (TFC) cells, requires the transcription factors Bcl6, E2A and Tcf1, whereas the transcriptional regulators Blimp1, Id3 and Id2 inhibit their development. We demonstrate that Blimp1 and E2A directly regulate Cxcr5 expression, and together with Bcl6 and Tcf1 form a transcriptional circuit that guides the TFC differentiation. The identification of a follicular subset of TC cells has far reaching implications for developing better strategies for the control of infections that target B cells and TFH cells and for the eradication of B cell derived malignancies. There is no associated input.
Project description:CD27 and CD45RA can be used to split T cells into 4 subsets, naïve cells, CD27+CD45RA+, central memory cells CD27+CD45RA-, effector memory cells CD27-CD45RA-, effector memory CD45RA re-expressing cell, CD27-CD45RA+. It is with in this final EMRA subset that it is belived the senenscent T cells reside. Cellular senescence is accompanied by a senescence-associated secretory phenotype (SASP), to date a SASP has not been demonstrated in T cells. We used microarray analysis to show primary human senescent CD8+ T cells also display a SASP comprising of chemokines, cytokines and extracellular matrix remodelling proteases. We also wanted to investigate whether p38MAPK regulated the SASP seen in EMRA T cells.
Project description:Many autoimmune diseases are characterized by the production of autoantibodies. The current view is that CD4+ Tfh cells are the main subset regulating autoreactive B cells. Here, we discover a novel CXCR5+PD1+ Tfh subset of CD8+ T cells whose development and function are negatively regulated by Stat5. These CD8+ Tfh cells regulate the GC B cell response and control autoantibody production. Deficiency of Stat5 in CD8+ T cells leads to an increase of CD8+ Tfh cells, resulting in the breakdown of B cell tolerance and autoantibody production. CD8+ Tfh cells share similar gene signatures with CD4+ Tfh cells and require CD40L/CD40 and TCR/MHCI interactions to deliver help to B cells. Our study highlights the diversity of follicular T cell subsets that contribute to the breakdown of B-cell tolerance
Project description:In human studies, mononuclear cells from peripheral blood (PBMC) often serve as a source of clinical study markers. Therefore, it is essential to understand to what extent phenotypes of PBMCs reflect their tissue-resident equivalents. In order to determine the heterogeneity of T-follicular helper (TFH) cells in peripheral blood versus tonsils, CD3+CD4+CD45RA–CXCR5+ cells of both origins were sorted and transcriptomes, TCR repertoires and cell-surface protein expression were analysed by single-cell RNA sequencing, flow cytometry and immunohistochemistry. Four subsets of TFH cells with classical T-follicular gene expression patterns were mostly found in tonsils. Interestingly, however, all circulating CD3+CD4+CXCR5+ T-cell subpopulations also appeared in tonsils. Still, when circulating, cells of the same cluster rather displayed markers of proliferation and migration, whereas their tonsillar counterparts exhibited known TFH characteristics resembling bona fide germinal center-typical TFH cell subtypes. Surprisingly, one distinct and oligoclonal CD4+CXCR5+ subpopulation displayed pronounced cytotoxic properties. Those ‘killer TFH (TFK) cells’ were found among PBMCs as well as tonsillar cells but were located outside of germinal centers. Accordingly, they were the only CD4+CXCR5+ T-cell subtype in tonsils featuring transcripts for CXCR3 and PSLG1. They appeared terminally differentiated and could be distinguished from all other TFH subsets by expression of NKG7 (TIA-1), granzymes, perforin, CCL5, CCR5, EOMES, CRTAM and CX3CR1. This hitherto undescribed subpopulation is indicative for chronic infection and inflammation and therefore is a valuable candidate to be included in any CD4+CXCR5+ TFH cell assessment.
Project description:Lymphocytic Choriomeningitis Virus (LCMV) specific CD8+ T cells (P14) were transferred into congenic WT mice followed by LCMV(DOCILE) infection. CXCR5-expressing (CXCR5+) or CXCR5 non-expressing (CXCR5-) P14 were purified on day 8 after infection, and total mRNA were sequenced from these populations. mRNA of P14 from uninfected mice (Naive P14) was also sequenced. Examination of mRNA level in CXCR5 expressing P14 (CXCR5+P14) and non-expressing P14 (CXCR5-P14) from LCMV infected mice day 8 post infection. mRNA of P14 from uninfected mice (Naïve P14) was also examined.