Project description:T follicular helper cells (TFH) are critical for the development and maintenance of germinal centers (GC) and humoral immune responses. During chronic HIV/SIV infection TFH accumulate, possibly as a result of antigen persistence. The HIV/SIV-associated TFH expansion may also reflect lack of regulation by suppressive follicular regulatory CD4+ T-cells (TFR). TFR are natural regulatory T-cells (TREG) that migrate into the follicle and, similarly to TFH, up-regulate CXCR5, Bcl-6, and PD1. Here we identified TFR as CD4+CD25+FoxP3+CXCR5+PD1hiBcl-6+ within lymph nodes of rhesus macaques (RM) and confirmed their localization within the GC by immunohistochemistry. RNA sequencing showed that TFR exhibit a distinct transcriptional profile with shared features of both TFH and TREG, including intermediate expression of FoxP3, Bcl-6, PRDM1, IL-10, and IL-21. In healthy, SIV-uninfected RM, we observed a negative correlation between frequencies of TFR and both TFH and GC B-cells as well as levels of CD4+ T-cell proliferation. Following SIV infection, the TFR/TFH ratio was reduced with no change in the frequency of TREG or TFR within the total CD4+ T-cell pool. Finally, we examined whether higher levels of direct virus infection of TFR were responsible for their relative depletion post-SIV infection. We found that TFH, TFR and TREG sorted from SIV- infected RM harbor comparable levels of cell-associated viral DNA. Our data suggests that TFR may contribute to the regulation and proliferation of TFH and GC B-cells in vivo and that a decreased TFR/TFH ratio in chronic SIV infection may lead to unchecked expansion of both TFH and GC B-cells. TFR, TFH, TREG and bulk CD4 cells were sorted from spleens of 5 uninfected and 5 infected RM.
Project description:Naive murine CD4+ T cells from GREAT/SMART-17A mice were cultured under Th1 or Tfh(1 ng/ml TGF-β)-polarizing conditions in 96-well plates coated with anti-CD3/anti-CD28 for 3.5 days; sorted by flow cytometry on IFNg+ (Th1), or CXCR5-IL17A+ (Th17) and CXCR5+IL17A- (Tfh); and subjected to bulk RNA-seq.
Project description:We found that a number of Tfh cells downmodulated BCL6 protein after their development, and we sought to compare the gene expression between BCL6-hi Tfh cells and BCL6-low Tfh cells. CD4+ T cells were sorted from immunized and non-immunized mice for RNA extraction and hybridization on Affymetrix microarrays. Bcl6yfp/+ OT-II cells were transferred to congenic recipient mice, and immunized with NP-OVA in CFA subcutaneously. Seven or ten days after immunization, cells were collected from draining lymph nodes, and sorted on FACSAria by the expression of CXCR5, PD-1 and BCL6-YFP. Naive CD4+ T cells were CD4+ CD44lo CD62Lhi cells from unimmunized mice.
Project description:We performed RNA-seq analysis of splenic samples from 8 individual mice sorted for LCMV-specific memory follicular B helper T cells (TFH) with or without aICOSL treatment (4 samples per group).
Project description:We identified Bach2 as factor to be expressed at low levels in Tfh cells. Induced overexpression of Bach2 in the germinal center reaction results in loss of the Tfh cell population. RNA-seq of sorted antigen-specific Tfh and non-Tfh cells 18 hours after induction of Bach2 overexpression allowed the simultaneous analysis of Bach2 regulated genes and genes differentially expressed in Tfh and non-Tfh cells.
Project description:Differential gene expression profile of Tfh and non-Tfh cells from both Wt and miR-155-/- mice spleens. Wt and miR-155-/- mice were immunized with OVA. 8 days post immunization, CD4+CXCR+PD1+ Tfh cells and CD4+CXCR5-PD1- non Tfh cells were sorted from mice spleens for analyses.
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:Cerebrospinal fluid (CSF) protects the central nervous system (CNS) and analyzing CSF aids the diagnosis of CNS diseases, but our understanding of CSF leukocytes remains superficial. Here, using single cell transcriptomics, we identified a specific border-associated composition and transcriptome of CSF leukocytes. Multiple sclerosis (MS) – an autoimmune disease of the CNS – increased transcriptional diversity in blood, but increased cell type diversity in CSF including a higher abundance of cytotoxic phenotype T helper cells. A new analytical approach, named cell set enrichment analysis (CSEA) identified a cluster-independent increase of follicular T helper (TFH) cells potentially driving the known expansion of B lineage cells in the CSF in MS. In mice, TFH cells accordingly promoted B cell infiltration into the CNS and the severity of MS animal models. Immune mechanisms in MS are thus highly compartmentalized and indicate ongoing local T/B cell interaction.
Project description:Analysis of transcriptome data identified 96, 64 and 3 genes that were differentially expressed (DE, adj. P value < 0.05) following abatacept treatment in Tfh, Treg and CD4+CD45RO+PD1+CXCR5- T cells, respectively. We determined if abatacept treatment altered the core transcriptional profiles of Tfh and Treg lineages by comparing gene expression of bulk sorted Treg and Tfh cells from cryopreserved PBMCs at baseline, week 24, and after abatacept withdrawal. Analysis of differentially expressed (DE) genes in Tfh was performed using Gene Ontology (GO) term enrichment analysis. This analysis revealed 9 significantly enriched GO categories, which were related to processes involved in cell division and proliferation. DE genes in the enriched GO categories showed a highly significant correlation in Tfh and Treg cells, further highlighting the similarity in the response of these two populations to abatacept. In contrast to Tfh and Treg, acatacept had a minimal impact on CD4+CD45RO+PD1+CXCR5- T cells.