Regulation of Innate T Cells in The Intestine
Vitamin A and its metabolite product retinoic acid (RA) play essential roles in the immune functions. The detailed mechanisms by which vitamin A and RA regulate immune cells, especially T cells, has been a topic of intense investigation recently. RA regulates the migration, function and proliferation of T cells. iNKT cells atypical T cells that recognize lipid molecules presented on CD1d molecules in mice. iNKT cells play vital roles in regulating immune responses and protecting the host from colitis. However, it has not been determined if RA can regulate iNKT cells. Our lab previously reported that RA regulates the survival of CD4+ T cells by enhancing the expression of an apoptosis-inducing purinergic receptor, P2X7. In this study, we investigated the impact of RA on the apoptosis and cytokine production of iNKT cells. We found that RA regulates the survival of intestinal iNKT cells by inducing P2X7 expression. In vitamin A-deficient mice, the expression of P2X7 on iNKT cells in the intestine was decreased, and the survival of iNKT cells, particularly CD69+ iNKT cells, was elevated. Nicotinamide adenine dinucleotide (NAD) induced apoptosis of iNKT cells in a P2X7-dependent manner, and P2X7 deficiency protected iNKT cells from apoptosis. Thus, we concluded that P2X7 regulates the size of effector iNKT cells populations in the intestine
Kim, Purdue University.
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