Project description:T follicular helper (Tfh) cells play a pivotal role in germinal center reactions, which requires Bcl6 transcription factor. To analyze their relationships with other effector T cell lineages and their stability in vivo, we developed and analyzed a new Bcl6 reporter mouse alone or together with other lineage reporter systems. Assisted with genome-wide transcriptome analysis, we show substantial plasticity of T cell differentiation in the early phase of immune response. At this stage, CXCR5 appears to be expressed in a Bcl6-independent manner. Once Bcl6 is highly expressed, Tfh cells can persist in vivo and some of them develop into memory cells. Together, our results indicate Bcl6 as a bona fide marker for Tfh polarized program. Three group of samples, with 2 biological replicates within each group and total of 6 samples were analyzed.
Project description:T follicular helper (Tfh) cells play a pivotal role in germinal center reactions, which requires Bcl6 transcription factor. To analyze their relationships with other effector T cell lineages and their stability in vivo, we developed and analyzed a new Bcl6 reporter mouse alone or together with other lineage reporter systems. Assisted with genome-wide transcriptome analysis, we show substantial plasticity of T cell differentiation in the early phase of immune response. At this stage, CXCR5 appears to be expressed in a Bcl6-independent manner. Once Bcl6 is highly expressed, Tfh cells can persist in vivo and some of them develop into memory cells. Together, our results indicate Bcl6 as a bona fide marker for Tfh polarized program.
Project description:Here we show a newly identified human Innate Lymphoid Cell population present in the follicles of tonsils and lymph nodes termed follicular regulatory ILCs (ILCFR). ILCFR have a distinct phenotype and transcriptional program when compared to other defined ILCs. Surprisingly, ILCFR inhibit the ability of follicular helper T (Tfh) cells to provide B cell help. The localization of ILCFR to the germinal centers suggests these cells may interfere with germinal center B cell (GC-B) and germinal center Tfh cell (GC-Tfh) interactions through the production of transforming growth factor beta (TGF-b). Intriguingly, under conditions of impaired GC-Tfh-GC-B cell interactions, such as human immunodeficiency virus (HIV) infection, the frequency of these cells is increased. Overall, we predict a role for ILCFR in regulating GC-Tfh-GC-B cell interactions and propose they expand in chronic inflammatory conditions.
Project description:T follicular helper (Tfh) cell is a unique T cell subset specialized in promoting germinal center reactions. Bcl6 has been identified as an obligatory transcription factor in Tfh cells; however, the molecular mechanism underlying Bcl6 function still remains unknown. Here, we combined genome-wide Bcl6 occupancy and transcriptome profiling to systemically analyze Bcl6 targets in Tfh cells. We found that Bcl6 exhibits unique binding preferences in Tfh cells from those in Th9, B cells and macrophage and its binding is closely associated with decrease in 5-hydroxymethylcytosine (5hmC). Importantly, Bcl6 directly binds to the IL-7R/CD127 gene and suppresses its expression. Bcl6 also binds the same sequences recognized by signal transducer and activator of transcription (STAT) 5, downstream of IL-7R. Bcl6 promotes CD127loPDhi Tfh cell differentiation; deletion of the Bcl6 gene in T cells results in enhanced IL-7R-STAT5 signaling and substantial expansion of CD127hiPDlo non-Tfh cells. Our study thus systemically examines Bcl6-controlled regulatory networks and provides novel insights into its biological functions in Tfh cells.
Project description:Bcl6 germline deletion causes a prominent inflammatory disease, owing to over-expression of Th2 cytokines, and affects the properties of B cells prior to immunization. Therefore we established the B cell-specific Bcl6 deletion mice and analyze the gene expression of naive B cells under physiological conditions. Total RNAs of splenic follicular and marginal zone B cells from Bcl6(flox/flox), Bcl6(+/flox) or Bcl6(+/+) mice heterozygous for mb1-cre were extracted and analysed on Affymetrix microarrays.
Project description:Gene expression data from wild-type and Bcl6-/- naive CD4 T cells In order to find genes regulated by Bcl6 in follicular helper T cells Naïve CD4 T cells were sorted from wild-type (WT) and T cell-specific conditional Bcl6-/- (KO) mice-- 8 samples, 4 WT and 4 KO