Project description:The goal of this study was to determine if there were differences in chromatin accessiblity between TFH and TEFF developing in Wild-type and IL6 KO 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 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:Transcriptional regulation of cell fate decisions in the immune system endows cells with specialized function; an iterative process that adapts to the changing landscape of infections. As coordinators of the immune system, T helper cells of the CD4+ lineage possess the ability to differentiate into an array of functional cell states in order to guide the response towards antibody production via the formation of T follicular helper (Tfh) cells or inflammation by the generation of T effector (Teff) cells. Tfh–Teff cell fate choice is mediated by the BCL6–Blimp-1 counter-antagonistic gene regulatory module, polarizing Tfh and Teff cells, respectively. A key question is how T helper cells establish and negotiate BCL6–Blimp-1 counter antagonism to control the output of Tfh and Teff cells. We show that the T cell receptor (TCR)-signal induced transcription factor, IRF4, is necessary for the generation of both BCL6-expressing Tfh cells and Blimp-1-expressing Teff cells. Importantly, we show that increasing TCR signal strength augments the amounts of IRF4 expressed as well as Teff cell fate trajectories that occur at the expense of Tfh cells. Using an orthogonal genetic system, based on a tet-inducible allele of Irf4, we demonstrate that increasing IRF4 expression during priming redirected Tfh cell fate choices towards those of Teff. Importantly, promotion of Teff cell fate trajectories by increased IRF4 expression occurred independently of IL-2 signals. At the molecular level, we link greater IRF4 abundance with its recruitment to low affinity DNA binding sites embedded within regulatory elements affiliated with the Teff gene program, including Blimp-1. Together, these results demonstrate that the Irf4 locus functions as the “reader” of TCR signal strength, in turn, the concentration dependent activity of the IRF4 transcription factor “writes” T helper cell fate choice.
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.
Project description:T follicular helper (Tfh) cells are a subset of CD4+ T helper (Th) cells that migrate into germinal centers and promote B cell maturation into memory B and plasma cells. Tfh cells are necessary for promotion of protective humoral immunity following pathogen challenge, but when aberrantly regulated, drive pathogenic antibody formation in autoimmunity and undergo neoplastic transformation in angioimmunoblastic T-cell lymphoma and other primary cutaneous T-cell lymphomas. Limited information is available on the expression and regulation of genes in human Tfh cells. Using a fluorescence activated cell sorting-based strategy, we obtained primary Tfh and non-Tfh T effector (Teff) cells from tonsils and prepared genome-wide maps of active, intermediate, and poised enhancers determined by ChIP-seq, with parallel transcriptome analyses determined by RNA-seq. Tfh cell enhancers were enriched near genes highly expressed in lymphoid cells or involved in lymphoid cell function, with many mapping to sites previously associated with autoimmune disease in genome-wide association studies. A group of active enhancers unique to Tfh cells associated with differentially expressed genes was identified. Fragments from these regions directed expression in reporter gene assays. These data provide a significant resource for studies of T lymphocyte development and differentiation and normal and perturbed Tfh cell function. Using a fluorescence activated cell sorting-based strategy, we obtained primary Tfh and non-Tfh T effector (Teff) cells from tonsils and prepared genome-wide maps of active, intermediate, and poised enhancers determined by ChIP-seq, with parallel transcriptome analyses determined by RNA-seq.
Project description:T follicular helper (Tfh) cells are a subset of CD4+ T helper (Th) cells that migrate into germinal centers and promote B cell maturation into memory B and plasma cells. Tfh cells are necessary for promotion of protective humoral immunity following pathogen challenge, but when aberrantly regulated, drive pathogenic antibody formation in autoimmunity and undergo neoplastic transformation in angioimmunoblastic T-cell lymphoma and other primary cutaneous T-cell lymphomas. Limited information is available on the expression and regulation of genes in human Tfh cells. Using a fluorescence activated cell sorting-based strategy, we obtained primary Tfh and non-Tfh T effector (Teff) cells from tonsils and prepared genome-wide maps of active, intermediate, and poised enhancers determined by ChIP-seq, with parallel transcriptome analyses determined by RNA-seq. Tfh cell enhancers were enriched near genes highly expressed in lymphoid cells or involved in lymphoid cell function, with many mapping to sites previously associated with autoimmune disease in genome-wide association studies. A group of active enhancers unique to Tfh cells associated with differentially expressed genes was identified. Fragments from these regions directed expression in reporter gene assays. These data provide a significant resource for studies of T lymphocyte development and differentiation and normal and perturbed Tfh cell function. Using a fluorescence activated cell sorting-based strategy, we obtained primary Tfh and non-Tfh T effector (Teff) cells from tonsils and prepared genome-wide maps of active, intermediate, and poised enhancers determined by ChIP-seq, with parallel transcriptome analyses determined by RNA-seq.
Project description:Follicular helper T (Tfh) cells access the B cell follicle to promote antibody responses, and are particularly important for germinal center (GC) reactions. However, the molecular mechanisms of how Tfh cells are physically associated with GCs are incompletely understood. Here we report that the sphingosine-1-phosphate receptor 2 (S1PR2) gene is highly expressed in a subpopulation of Tfh cells that localizes in GCs. S1PR2-deficient Tfh cells exhibited reduced accumulation in GCs due to their impaired retention. T cells deficient in both S1PR2 and CXCR5 were ineffective in supporting GC responses compared to T cells deficient only in CXCR5. These results suggest that S1PR2 and CXCR5 cooperatively regulate localization of Tfh cells in GCs to support GC responses. Venus-high Tfh, Venus-low Tfh, PD1-intermediate Th, PD1-low Th and naïve CD4+ T cells were sorted on FACSAria from immunized S1pr2V/+ mice or control mice for RNA extraction and hybridization on Affimetrix microarrays.
Project description:This study seeks a better understanding of the functional differences emerging between mouse CD8+ T effector (Teff) cells infiltrating three distinct mucosal environments; the small intestine, the lung and the liver. CD8+ Teff cells immigrating in the target organs were generated using a murine experimental acute graft versus host disease (aGVHD) model. For this purpose, congenially labeled CD45.1 OT-I CD8+ Teff cells were transplanted to and activated in a lethally irradiated allogeneic CD45.2 host constitutively expressing their cognate antigen, the chicken ovalbumin protein. CD8+ Teff cells were retrieved from their respective organ environments by automated organ disintegration and MACS sorting, and compared with each other by whole genome gene expression profiling. Peripheral blood derived circulating CD8+ Teff cells were also analyzed, serving as circulating peripheral T effector cell controls