Project description:T follicular helper (Tfh) cells constitute an essential cell type in the induction of antibodies. We report that CD4 T cells lacking Foxo1 almost uniformly became CXCR5int Tfh cells following immunization. Moreover, a Foxo1 loss-of-function complemented an Icos mutation allowing the appearance of Tfh cells along with follicular, class-switched B cells and IgG isotype anti-DNA antibodies. Similarly, FOXO1 deficient Tfh differentiation displayed a substantially reduced dependence on ICOSL. Functional and molecular analyses show that FOXO1 regulates Tfh differentiation through a broad program of gene expression exemplified by positive regulation of Icos and negative regulation of Bcl6. These results demonstrate that a key step in Tfh differentiation is the ICOS-initiated activation of the PI3K-AKT pathway resulting in the inactivation of FOXO1. Performed ChIP-seq analysis to examine the role of foxo1 in the development of Tfh cells
Project description:The maintenance of the TFH phenotype depends on continuous signals via ICOS. For a global assessment of differences in gene expression after interruption of the ICOS pathway a genome wide transcriptome analysis was performed. We used the OT-II adoptive transfer system to isolate antigen-specific TFH cells (day 6 after immunization) after short-term (6 hours) blockade of the ICOS pathway using a monoclonal antibody against ICOS-L. Gene expression profiles of TFH cells with or without ICOS-L blockade. Affymetrix MG 430 2.0 whole genome arrays were performed in duplicates for the control and blockade group (4 arrays in total). To obtain genes significantly regulated upon ICOS L blockade, the expression profiles of TFH cells treated with an isotype control or anti-ICOS-L antibody were compared to each other. After total RNA extraction, reverse transcription, cDNA extraction, the biotinylated cRNA was transcribed, fragmented, and 15 M-BM-5g cRNA hybridized in duplicates for each of the two groups to the 4 GeneChip arrays: Group1 TFH cells control, Group2 TFH cells ICOS-L blockade.
Project description:T follicular helper (Tfh) cells are essential in the induction of high-affinity, class-switched antibodies. The differentiation of Tfh cells is a multi-step process that depends upon the co-receptor ICOS and the activation of phosphoinositide-3 kinase leading to the expression of key Tfh cell genes. We report that ICOS signaling inactivates the transcription factor FOXO1, and a Foxo1 genetic deletion allowed for generation of Tfh cells with reduced dependence on ICOS ligand. Conversely, enforced nuclear localization of FOXO1 inhibited Tfh cell development even though ICOS was overexpressed. FOXO1 regulated Tfh cell differentiation through a broad program of gene expression exemplified by its negative regulation of Bcl6. Final differentiation to germinal center Tfh cells (GC-Tfh) was instead FOXO1 dependent as the Foxo1(-/-) GC-Tfh cell population was substantially reduced. We propose that ICOS signaling transiently inactivates FOXO1 to initiate a Tfh cell contingency that is completed in a FOXO1-dependent manner.
Project description:Expression Data from WT and Sh2d1a-/- in vivo follicular helper CD4 T cells (TFH) versus non follicular helper CD4 T cells (non-TFH)
Project description:After activation, CD4+ helper T (Th) cells differentiate; into distinct effector subsets. Although chemokine; (C-X-C motif) receptor 5-expressing T follicular; helper (Tfh) cells are important in humoral immunity,; their developmental regulation is unclear. Here we; show that Tfh cells had a distinct gene expression; profile and developed in vivo independently of the; Th1 or Th2 cell lineages. Tfh cell generation was regulated; by ICOS ligand (ICOSL) expressed on B cells; and was dependent on interleukin-21 (IL-21), IL-6,; and signal transducer and activator of transcription; 3. However, unlike Th17 cells, differentiation of Tfh; cells did not require transforming growth factor; b (TGF-b) or Th17-specific orphan nuclear receptors; RORa and RORg in vivo. Finally, naive T cells activated; in vitro in the presence of IL-21 but not; TGF-b signaling preferentially acquired Tfh gene; expression and promoted germinal-center reactions; in vivo. This study thus demonstrates that Tfh is a; distinct Th cell lineage. Experiment Overall Design: Splenic CD4+CXCR5+ T cells were isolated from KLH-immunized mice and restimulated with anti-CD3 for 4 hours before total RNA preparation. Affymetrix gene chips were used to analyze their gene expression.
Project description:To characterize the effect of loss of Ets1 in Non-TFH and TFH cells, we performed gene expression RNAseq analysis for T follicular helper (TFH) and Non-T follicular helper (Non-TFH) cells in WT (Ets1 fl/fl) and Ets1 KO (CD4-cre Ets1 fl/fl) mice.
Project description:After activation, CD4+ helper T (Th) cells differentiate into distinct effector subsets. Although chemokine (C-X-C motif) receptor 5-expressing T follicular helper (Tfh) cells are important in humoral immunity, their developmental regulation is unclear. Here we show that Tfh cells had a distinct gene expression profile and developed in vivo independently of the Th1 or Th2 cell lineages. Tfh cell generation was regulated by ICOS ligand (ICOSL) expressed on B cells and was dependent on interleukin-21 (IL-21), IL-6, and signal transducer and activator of transcription 3. However, unlike Th17 cells, differentiation of Tfh cells did not require transforming growth factor b (TGF-b) or Th17-specific orphan nuclear receptors RORa and RORg in vivo. Finally, naive T cells activated in vitro in the presence of IL-21 but not TGF-b signaling preferentially acquired Tfh gene expression and promoted germinal-center reactions in vivo. This study thus demonstrates that Tfh is a distinct Th cell lineage.
Project description:The maintenance of the TFH phenotype depends on continuous signals via ICOS. For a global assessment of differences in gene expression after interruption of the ICOS pathway a genome wide transcriptome analysis was performed. We used the OT-II adoptive transfer system to isolate antigen-specific TFH cells (day 6 after immunization) after short-term (6 hours) blockade of the ICOS pathway using a monoclonal antibody against ICOS-L.
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.