[HTML][HTML] Crucial roles of XCR1-expressing dendritic cells and the XCR1-XCL1 chemokine axis in intestinal immune homeostasis

T Ohta, M Sugiyama, H Hemmi, C Yamazaki, S Okura… - Scientific reports, 2016 - nature.com
T Ohta, M Sugiyama, H Hemmi, C Yamazaki, S Okura, I Sasaki, Y Fukuda, T Orimo, KJ Ishii
Scientific reports, 2016nature.com
Intestinal immune homeostasis requires dynamic crosstalk between innate and adaptive
immune cells. Dendritic cells (DCs) exist as multiple phenotypically and functionally distinct
sub-populations within tissues, where they initiate immune responses and promote
homeostasis. In the gut, there exists a minor DC subset defined as CD103+ CD11b− that
also expresses the chemokine receptor XCR1. In other tissues, XCR1+ DCs cross-present
antigen and contribute to immunity against viruses and cancer, however the roles of XCR1+ …
Abstract
Intestinal immune homeostasis requires dynamic crosstalk between innate and adaptive immune cells. Dendritic cells (DCs) exist as multiple phenotypically and functionally distinct sub-populations within tissues, where they initiate immune responses and promote homeostasis. In the gut, there exists a minor DC subset defined as CD103+CD11b that also expresses the chemokine receptor XCR1. In other tissues, XCR1+ DCs cross-present antigen and contribute to immunity against viruses and cancer, however the roles of XCR1+ DCs and XCR1 in the intestine are unknown. We showed that mice lacking XCR1+ DCs are specifically deficient in intraepithelial and lamina propria (LP) T cell populations, with remaining T cells exhibiting an atypical phenotype and being prone to death and are also more susceptible to chemically-induced colitis. Mice deficient in either XCR1 or its ligand, XCL1, similarly possess diminished intestinal T cell populations and an accumulation of XCR1+ DCs in the gut. Combined with transcriptome and surface marker expression analysis, these observations lead us to hypothesise that T cell-derived XCL1 facilitates intestinal XCR1+ DC activation and migration and that XCR1+ DCs in turn provide support for T cell survival and function. Thus XCR1+ DCs and the XCR1/XCL1 chemokine axis have previously-unappreciated roles in intestinal immune homeostasis.
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