Project description:We show here that the T helper-fate is not fixed and that mature antigen-stimulated CD4 T cells can switch off Thpok expression and reactivate CD8- lineage genes. This unexpected plasticity results in the post-thymic termination of the T helper- program and the functional differentiation of distinct MHC class II restricted CD4 cytotoxic T lymphocytes Small intestine CD4 intraepithelial T lymphocytes from ThPOK-GFP reposter mice were isolated and sorted (FACS Aria) based on ThPOK and CD8aa expression. Cell were isolated either from non-experimental ThPOK-GFP reporter mice (WT) or after transfering CD4 naive T cells from ThPOK-GFP reporter mice to RAG-/-recipient animals (TR) as an experimental colitis model. Experimet was done in duplicate.
Project description:Microbial sequencing revealed progressive reduction of gut microbiota that showed some differences in the two ABX groups compared to untreated controls. Interestingly, duration of ABX was associated with a gradual disappearance of the CD4+ and CD4+CD8+ subset of gut intraepithelial lymphocytes (IELs). This IEL subset is microbiota-dependent and is absent in germ-free mice. Relative abundance of Lactobacillus reuteri correlated with frequencies of CD4+CD8+ IELs and reduced EAU. Notably, IELs in culture suppressed antigen-specific activation of autoreactive T cells.
Project description:Mouse small intestine intraepithelial lymphocytes (IEL) that express a ab TCR and CD8aa homodimers are an enigmatic T cell subset, as their specificity and in vivo function remain to be defined. To gain insight into the nature of these cells, we performed global gene expression profiling using microarray analysis, combined with PCR and flow cytometry to determine the level of expression of selected genes. Using these methods, TCR ab+ CD8aa IEL were compared to their TCR ab+ CD8b+ and TCR gd+ counterparts. Experiment Overall Design: In this study, the three IEL populations were isolated by cell sorting from a pool of IELs from 20 mice. RNA from each IEL subset was used to probe one microarray. A replicate experiment was performed on a seperate occasion using a new pool of 20 mice and three additional microarrays were used.
Project description:The gut epithelium is populated by intraepithelial lymphocytes (IELs), a heterogeneous T cell population with cytotoxic and regulatory properties, which can be imprinted on CD4+ T cells at the epithelium. However, the role of the T cell receptor (TCR) in this process remains unclear. Single-cell transcriptomic analyses revealed distinct clonal expansions between cell states, with CD4-IELs being one of the least diverse populations. Conditional deletion of TCR on differentiating CD4+ T cells or of MHCII on intestinal epithelial cells prevented CD4-IEL differentiation. However, TCR ablation on differentiated CD4-IELs, or long-term cognate antigen withdraw, did not affect their maintenance. TCR re-engaging of antigen-specific CD4-IELs during Listeria monocytogenes infection did not alter their state but correlated with reduced bacteria invasion. Thus, local antigen recognition is an essential signal for differentiation of T cells at the epithelium but differentiated CD4-IELs are able to preserve an effector program in the absence of TCR signaling.
Project description:CD8αβ+ intraepithelial lymphocytes (IELs) are a subset of “effector-memory-like” T cells scattered along the intestinal epithelium. To investigate if CD8αβ+ IEL can function in ways other than the conventional cytotoxic effect of CD8αβ+ T cells,CD8αβ+ IELs were compared with CD8αβ+ splenocytes (SPL) by RNA-seq. We used microarrays to identify new functions of CD8αβ+ IELs .
Project description:To under the role of Kdm6b in the regulation of intestinal TCRβ+CD8αα+ intraepithelial lymphocytes (IELs), Kdm6b was conditionally deleted in mouse T cells. Small intestinal TCRβ+CD8αα+ IELs were sorted by flow cytometry and RNA-seq was conducted to identify the differentially expressed genes.
Project description:We performed CUT&Tag-Seq against histone H3K27me3 in mouse small intestinal TCRβ+CD8αα+ intraepithelial lymphocytes (IELs) of wild-type mice to analyze epigenetic modifications.
Project description:The microbiome contributes to the development and maturation of the immune system. In response to commensal bacteria, intestinal CD4+ T lymphocytes differentiate into functional subtypes with regulatory or effector functions. Whereas the development of small intestine intraepithelial lymphocytes that express CD4 and CD8aa homodimers (CD4IELs) depends on the microbiota, the identity of the microbial antigens recognized by CD4+ T cells that can differentiate into CD4IELs remains unknown. We identified B-hexosaminidase, a conserved enzyme across commensals of the Bacteroidetes phylum, as a driver of CD4IEL differentiation. In a mouse model of colitis, B-hexosaminidase-specific lymphocytes protected against intestinal inflammation. Thus, T cells of a single specificity can recognize a variety of abundant commensals and elicit a regulatory immune response at the intestinal mucosa.