Project description:TFH and Th1 cells generated after viral or intracellular bacterial infections are critical for the control of infections and the development of immunological memories. However, the mechanisms that govern the choice of activated CD4 T cells to the two alternative fates remain unclear. Here, we found that reciprocal expression of TCF1 and Blimp1 between viral-specific TFH and Th1 cells started early after infection. TCF1 was intrinsically required for the differentiation of TFH cells. In the absence of TCF1, TFH cells failed to maintain their transcriptional and metabolic signatures, distinct from those in Th1 cells. Mechanistically, TCF1 functioned through forming negative feedback loops with IL-2 and Blimp1 signaling. Thus, we have demonstrated an essential role of TCF1 in TFH-cell differentiation. Tcf7 deficient and WT SMARTA CD4 T cells were isolated from mice 8 days after Lymphocytic Choriomeningitis Virus (LCMV) infection. TFH and Th1 cells were separated by FACS.
Project description:CD4 T cell help is critical for both the generation and maintenance of germinal centers, and T follicular helper (TFH) cells are the CD4 T cell subset required for this process. SAP (SH2D1A) expression in CD4 T cells is essential for germinal center development. However, SAP-deficient mice have only a moderate defect in TFH differentiation as defined by common TFH surface markers. CXCR5+ TFH cells are found within the germinal center as well as along the boundary regions of T/B cell zones. Here we show that germinal center associated T cells (GC TFH) can be identified by their co-expression of CXCR5 and the GL7 epitope, allowing for phenotypic and functional analysis of TFH and GC TFH populations. Here we show GC TFH are a functionally discrete subset of further polarized TFH cells, with enhanced B cell help capacity and a specialized ability to produce IL-4 in a TH2-independent manner. Strikingly, SAP-deficient mice have an absence of the GC TFH subset and SAP- TFH are defective in IL-4 and IL-21 production. We further demonstrate that SLAM (Slamf1, CD150), a surface receptor that utilizes SAP signaling, is specifically required for IL-4 production by GC TFH. GC TFH cells require IL-4 and IL-21 production for optimal help to B cells. These data illustrate complexities of SAP-dependent SLAM family receptor signaling, revealing a prominent role for SLAM receptor ligation in IL-4 production by germinal center CD4 T cells but not in TFH and GC TFH differentiation. Analysis of in vivo polyclonal GC Tfh vs Tfh vs Non-Tfh eight days after LCMV viral infection. Analysis of in vivo follicular helper CD4 T cells (CXCR5high GL7low), versus germinal center follicular helper CD4 T cells (CXCR5hi GL7hi), versus non-follicular helper CD4 T cells (CXCR5low) eight days after viral infection.
Project description:TFH and Th1 cells generated after viral or intracellular bacterial infections are critical for the control of infections and the development of immunological memories. However, the mechanisms that govern the choice of activated CD4 T cells to the two alternative fates remain unclear. Here, we found that reciprocal expression of TCF1 and Blimp1 between viral-specific TFH and Th1 cells started early after infection. TCF1 was intrinsically required for the differentiation of TFH cells. In the absence of TCF1, TFH cells failed to maintain their transcriptional and metabolic signatures, distinct from those in Th1 cells. Mechanistically, TCF1 functioned through forming negative feedback loops with IL-2 and Blimp1 signaling. Thus, we have demonstrated an essential role of TCF1 in TFH-cell differentiation.
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:CD4 T cell help is critical for both the generation and maintenance of germinal centers, and T follicular helper (TFH) cells are the CD4 T cell subset required for this process. SAP (SH2D1A) expression in CD4 T cells is essential for germinal center development. However, SAP-deficient mice have only a moderate defect in TFH differentiation as defined by common TFH surface markers. CXCR5+ TFH cells are found within the germinal center as well as along the boundary regions of T/B cell zones. Here we show that germinal center associated T cells (GC TFH) can be identified by their co-expression of CXCR5 and the GL7 epitope, allowing for phenotypic and functional analysis of TFH and GC TFH populations. Here we show GC TFH are a functionally discrete subset of further polarized TFH cells, with enhanced B cell help capacity and a specialized ability to produce IL-4 in a TH2-independent manner. Strikingly, SAP-deficient mice have an absence of the GC TFH subset and SAP- TFH are defective in IL-4 and IL-21 production. We further demonstrate that SLAM (Slamf1, CD150), a surface receptor that utilizes SAP signaling, is specifically required for IL-4 production by GC TFH. GC TFH cells require IL-4 and IL-21 production for optimal help to B cells. These data illustrate complexities of SAP-dependent SLAM family receptor signaling, revealing a prominent role for SLAM receptor ligation in IL-4 production by germinal center CD4 T cells but not in TFH and GC TFH differentiation. Analysis of in vivo antigen-specific (LCMV-specific, SMARTA TCR transgenic) WT and Sh2d1a-/- follicular helper CD4 T cells (CXCR5high),versus non-follicular helper CD4 T cells (CXCR5low), eight days after viral infection.
Project description:T follicular helper (TFH) cells promote affinity maturation of B cells in germinal centers (GCs), whereas T follicular regulatory (TFR) cells limit GC reaction. Store-operated Ca2+ entry (SOCE) through Ca2+ release-activated Ca2+ (CRAC) channels mediated by STIM and ORAI proteins is a fundamental signaling pathway in T lymphocytes. Here we show that SOCE is required for the differentiation and function of both TFH and TFR cells. Conditional deletion of Stim1 and Stim2 genes in T cells or Treg cells results in spontaneous autoantibody production and humoral autoimmunity. Conversely, antibody-mediated immune responses following viral infection critically depend on SOCE in TFH cells. Mechanistically, STIM1 and STIM2 control early TFR and TFH cell differentiation through NFAT-mediated IRF4, BATF and Bcl-6 expression. SOCE plays a dual role in GC response by controlling TFH and TFR cell function, thus enabling protective B cell responses and preventing humoral autoimmunity. RNAseq analyses of WT and Stim1Stim2 DKO follicular T cells and non-follicular T cells; 4-6 mice per cohort in duplicates. Mice were infected for 10 days with LCMV.
Project description:Chronic viral infections are characterized by a state of CD8 T cell dysfunction termed exhaustion. A better understanding of the mechanisms that regulate CD8 T cell responses during chronic infection is required to improve immunotherapies that restore function in exhausted CD8 T cells. Here we identify a novel population of virus-specific CD8 T cells with a T follicular helper (Tfh)-like signature in mice chronically infected with lymphocytic choriomeningitis virus (LCMV). These Tfh-like CD8 T cells expressed the programmed cell death-1 (PD-1) inhibitory receptor but at the same time also expressed co-stimulatory molecules and had a gene signature that was related to CD8 T cell memory precursor cells and hematopoietic stem cells (HSC). These Tfh-like CD8 T cells acted as stem cells during chronic infection undergoing self-renewal and also differentiating into the terminally exhausted CD8 T cells that were present in both lymphoid and non-lymphoid tissues. The Tfh-like CD8 T cells were found only in lymphoid tissues and resided predominantly in the T cell zones along with naïve CD8 T cells. Interestingly, the proliferative burst after PD-1 blockade came almost exclusively from this Tfh-like CD8 T cell subset. Importantly, the transcription factor TCF1 played a cell intrinsic and essential role in the generation of Tfh-like CD8 T cells. Taken together, our study identifies Tfh-like CD8 T cells as the critical subset for maintaining the pool of virus-specific CD8 T cells during chronic infection and as the cells that proliferate after PD-1 blockade. These findings provide a better understanding of T cell exhaustion and have implications towards optimizing PD-1 directed immunotherapy. 8 samples isolated from CD8 T-cells in LCMV clone 13 GK1.5 infected mice (2 naïve, 3 CXCR5+Tim3-, 3 CXCR5-Tim3+) cells were analyzed
Project description:The goal of this study is to determine the impact of Tcf1 and Lef1 deficiency on T follicular helper (Tfh) cells elicited by protein immunization. We demonstrate that although phenotypic Tcf1/Lef1-deficient Tfh cells were able to develop in response to vaccination, they are functionally impaired. Mechanisc studies reveal the direct regulatory effect by Tcf1 and Lef1 on transcriptome and chromatin accessibility in vaccine-elicited Tfh cells. Analysis of chromatin accessibility in WT and Tcf1/Lef1-deficient Tfh cells eliciated by vaccination.
Project description:The goal of this study is to determine the impact of Tcf1 and Lef1 deficiency on T follicular helper (Tfh) cells elicited by protein immunization. We demonstrate that although phenotypic Tcf1/Lef1-deficient Tfh cells were able to develop in response to vaccination, they are functionally impaired. Mechanisc studies reveal the direct regulatory effect by Tcf1 and Lef1 on transcriptome and chromatin accessibility in vaccine-elicited Tfh cells.
Project description:The goal of this study is to determine the impact of Tcf1 and Lef1 deficiency on T follicular helper (Tfh) cells elicited by protein immunization. We demonstrate that although phenotypic Tcf1/Lef1-deficient Tfh cells were able to develop in response to vaccination, they are functionally impaired. Mechanisc studies reveal the direct regulatory effect by Tcf1 and Lef1 on transcriptome and chromatin accessibility in vaccine-elicited Tfh cells.