Project description:CD4 T follicular helper (Tfh) cells provide the required signals to B cells for germinal center reactions that are necessary for longlived antibody responses. However, it remains unclear whether there are CD4+ memory T cells committed to the Tfh lineage after antigen clearance. Using adoptive transfer of antigen-specific memory CD4+ subpopulations (based on CXCR5 and Ly6c expression)in the LCMV infection model, we found that there are distinct memory CD4+ T cell populations with commitment to the Tfh and Th1 lineages. Our conclusions are based on gene expression profiles, epigenetic studies and phenotypic and functional analysis. The gene expression profiles of virus-specific CD4 T cell subets at effector and memory stages is presented here. The SMARTA TCR transgenic / adptive transfer system was used to identify and sort subsets of antigen-specific CD4 T cells (based on their expression of Ly6c and CXCR5) elicited after acute infection with LCMV (Arm).
Project description:Comparison of transcriptome between early Tfh vs. early Th1 cells Blimp-1-YFP LCMV gp specific TCRtg Smarta cells were transferred into B6 mice, which were then infected with LCMV Armstrong. On day 3 after infection, splenocytes were stained to sort Blimp-1-YFP+IL-2Ra+ Th1 cells or Blimp-1-YFP-IL-2Ra- Tfh cells for RNAseq analysis. Contributor: LIAI RNAi center (LIAI)
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:Trascriptional analysis of CD2 hi and CD25 lo CD4+ effector T cells during acute viral infection. SMARTA cells were transferred into B6 mice, followed by infection with LCMV. At day 5 post-infection, CD25 hi and CD25 lo SMARTA cells were isolated from the spleen by FACS. Consistent with our prior studies showing that CD25 lo early effector cells give rise to both Tfh effector cells and memory T cells, we observed gene expression in the CD25 lo population consistent with Tfh differentiation. Conversely, CD25 hi effector cells expressed markers consistent with Th1 differentiation and short-term survival.
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:Comparison of transcriptome between GFP-RV+ Th1 cells and Lef1-RV+ Th1 cells B6 mice received GFP-RV+ or Lef1-RV+ LCMV gp specific TCRtg Smarta cells and were infected with LCMV. On four days after infection, splenocytes were collected to sort CXCR5- Th1 cells per genotype. Contributor: LIAI RNAi Center (LIAI)
Project description:In this study, we sought to distinguish phenotypically and functionally distinct virus-specific effector CD4 T cell subsets that form during acute lymphocytic choriomeningitis virus (LCMV) infection and to examine their ability to develop into memory T cells. To further characterize the effector subsets and identify genetic pathways and transcription factors involved in their differentiation, we performed genome-wide gene expression profiling of the three day 8 effector cell populations: (1) PSGL1hi Ly6Chi, (2) PSGL1hi Ly6Clo and (3) PSGL1lo Ly6Clo Smarta CD4 T cells along with (4) day 60 memory PSGL1hi and (5) naïve Smarta CD4 T cells using Illumina BeadChips. Results of this microarray confirmed the validity of our phenotyping by flow cytometry in many ways and showed distinct gene signatures for the three effector subsets. DNA microarray analysis was performed on two or three independent samples of five different Smarta CD4 T cell populations: (1) naïSGL1lo, (3) day 8 PSGL1hi Ly6Clo, (4) day 8 PSGL1hi Ly6Clo and (5) day 60 PSGL1hi memory cells.
Project description:Following infection with LCMV, CD4+ SMARTA TCR transgenic cells (specific for the gp61-80 epitope of the LCMV glycoprotein) rapidly expand, become effector cells, and go on to form a long-lived memory population. Following infection with a recombinant Listeria monocytogenes expressing the LCMV epitope gp61-80, SMARTA cells also expand but display defective effector differentiation and fail to form memory. In an attempt to understand the signals required for CD4 T cell memory differentiation, we compared gene expression by SMARTA cells at the peak of the primary response following either Lm-gp61 or LCMV infection. Experiment Overall Design: SMARTA cells were purified at day 7 post-infection with either LCMV or Lm-gp61. SMARTA cells were sorted on the basis of Thy1.1 expression using a FACSAria. Cells were sorted through the machine twice to enhance purity. Two biological replicates of each group are provided. Each replicate represents the results of SMARTA pooled from three animals.
Project description:CD4 T follicular helper (Tfh) cells provide the required signals to B cells for germinal center reactions that are necessary for longlived antibody responses. However, it remains unclear whether there are CD4+ memory T cells committed to the Tfh lineage after antigen clearance. Using adoptive transfer of antigen-specific memory CD4+ subpopulations (based on CXCR5 and Ly6c expression)in the LCMV infection model, we found that there are distinct memory CD4+ T cell populations with commitment to the Tfh and Th1 lineages. Our conclusions are based on gene expression profiles, epigenetic studies and phenotypic and functional analysis. The gene expression profiles of virus-specific CD4 T cell subets at effector and memory stages is presented here.