Project PXD023140 Tissue adaptation is the dominant driver of the proteomic landscape of intestinal intraepithelial lymphocytes

Intestinal intraepithelial T lymphocytes (T-IEL) patrol the single layer of epithelial cells lining the gut, and consist of both induced T-IEL, derived from systemic antigen-experienced lymphocytes, and natural IEL, that are developmentally targeted to the intestine. To gain functional insights into these enigmatic cells, we used high-resolution quantitative mass spectrometry to investigate the proteomic landscape of the main T-IEL populations in the gut. Comparing the proteomes of induced T-IEL, tissue-resident memory TCRαβ+ CD8αβ+ cells and natural TCRγδ+ CD8αα+ and TCRαβ+ CD8αα+ T-IEL, with naive CD8+ T cells from lymph nodes reveals striking similarities between T-IEL subsets and the dominant effect of the gut environment on T-IEL phenotypes. Analysis of copy numbers/cell of >7000 proteins provides new understanding of the differences in composition of T cell antigen receptor signal transduction pathways in T-IEL versus conventional T cells and reveals skewing of the metabolic machinery towards an exhausted T cell phenotype adapted to the intestinal environment. This study provides a resource for exploring and understanding how multiple inputs are integrated into T-IEL function.