Project description:Unprimed mice harbor a substantial population of "memory-phenotype" CD8+ T cells (CD8-MP cells) that exhibit hallmarks of activation and innate-like functional properties. Due to the lack of faithful markers to distinguish CD8-MP cells from bona fide CD8+ memory T cells, the developmental origins and antigen specificities of CD8-MP cells remain incompletely defined. Using deep T cell receptor (TCR) sequencing, we found that the TCRs expressed by CD8-MP cells are highly recurrent and distinct from the TCRs expressed by naive-phenotype CD8+ T cells. CD8-MP clones exhibited reactivity to widely expressed self-ligands. T cell precursors expressing CD8-MP TCRs upregulated the transcription factor Eomes during maturation in the thymus, prior to induction of the full memory phenotype, suggestive of a unique program triggered by recognition of self-ligands. Moreover, CD8-MP cells infiltrate oncogene-driven prostate tumors and express high densities of PD-1, suggesting a potential role in anti-tumor immunity and response to immunotherapy.
Project description:Memory CD8+ T cells have the ability to provide lifelong immunity against pathogens. Although memory features generally arise after challenge with a foreign antigen, naïve CD8 single positive (SP) thymocytes may acquire phenotypic and functional characteristics of memory cells in response to cytokines such as interleukin-4. This process is associated with the induction of the T-box transcription factor Eomesodermin (EOMES). However, the underlying molecular mechanisms remain ill-defined. Using epigenomic profiling, we show that these innate memory CD8SP cells acquire only a portion of the active enhancer repertoire of conventional memory cells. This reprograming is secondary to EOMES recruitment, mostly to RUNX3-bound enhancers. Furthermore, EOMES is found within chromatin-associated complexes containing BRG1 and promotes the recruitment of this chromatin remodelling factor. Also, the in vivo acquisition of EOMES-dependent program is BRG1-dependent. In conclusion, our results support a strong epigenetic basis for the EOMES-driven establishment of CD8+ T cell innate memory program.
Project description:Tissue-resident memory CD8+ T cells (TRM) constitute a non-circulating memory T cell subset that provides early protection against re-infection. However, how TRM arise from antigen-triggered T cells has remained unclear. Exploiting the TRM-restricted expression of Hobit, we developed TRM reporter/deleter mice to study TRM differentiation. We found that Hobit was upregulated in a subset of LCMV-specific T cells located within peripheral tissues during the effector phase of the immune response. These Hobit+ effector T cells were identified as TRM precursors, given that their depletion substantially decreased TRM development, but not the formation of circulating memory T cells. Adoptive transfer experiments of Hobit+ effector T cells corroborated their biased contribution to the TRM lineage. Transcriptional profiling of Hobit+ effector T cells underlined the early establishment of TRM properties including downregulation of tissue exit receptors and upregulation of TRM-associated molecules. Importantly, we identified Eomes as a key factor instructing the early bifurcation of circulating and resident lineages. These findings establish that commitment of TRM occurs early in antigen-driven T cell differentiation and reveal the molecular mechanisms underlying this differentiation pathway.
Project description:Eomesodermin (Eomes) is a transcription factor with a crucial role regulating cytotoxic function, development and survival of immune cells. Although it is known that γδ T cells can express Eomes, its function on those cells is still largely unknown. Using Eomes-IRES-GFP mice we were able to sort for Eomes+ and Eomes‒ γδ T cells populations and get their gene expression profiles, bringing light to the role of Eomes on γδ T cells.
Project description:Antigen presentation by cortical and medullary thymic epithelial cells (cTEC and mTEC) ensures the formation of a self-restricted and self-tolerant T cell repertoire, respectively. As such, a broad diversity of self-antigens needs to be presented by mTEC to induce T cell’s self-tolerance. Even though the expression and antigen presentation of protein coding genes in mTEC has been abundantly described, little is known of the implication of allegedly noncoding regions of the genome to tolerance induction. In this study, we focused on transposable elements (TE), which have been shown to be highly expressed by mTEC.
Project description:High amount of Eomes might drive T cell exhaustion. In order to understand how Eomes contributes to exhaustion of CD8+ T cell in the TME as a transcription factor, we conducted anti-Eomes ChIPseq analysis of control OT-I cells and Eomes-overexpressing OT-I cells.
Project description:T-bet and Eomes are related T-box transcription factors that control NK cell development. This study was designed to understand the specific roles of Eomes and T-bet in regulating gene expression. RNAseq data were generated for immature (CD11b- CD27+) and mature (CD11b+ CD27-) NK cells from T-bet KO (Tbet Ho) or control mice (Tbet WT) or from Eomes KO (Eomes Ho) or control mice (NK-Cre). Three samples were generated for each condition (Tri 1, 2, 3).