CD90(+)CD45(-) intraperitoneal mesothelial-like cells inhibit T cell activation by production of arginase I.

Cellular immunology

PubMedID: 24556645

Kitayama J, Emoto S, Yamaguchi H, Ishigami H, Yamashita H, Seto Y, Matsuzaki K, Watanabe T. CD90(+)CD45(-) intraperitoneal mesothelial-like cells inhibit T cell activation by production of arginase I. Cell Immunol. 2014;288(1-2):8-14.
In this study, we analyzed intraperitoneal cells recovered from human samples and found that CD90(+)CD45(-) cells exist as a minor population but vigorously grow in culture, showing the morphological features of mesothelial cells (MC). Interestingly, the MC highly expressed arginase I and markedly suppressed T cell proliferation with the reduction of CD3 ? chain expression in T cells stimulated by coated anti-CD3 mAb. The addition of nor-NOHA (500┬ÁM), or l-arginine (1mM) mostly restored the inhibitory effect of MC on T cell proliferation as well as the reduced expression of CD3 ? chain. The expression level of CD3 ? chain in T cells in the peritoneal cavity was significantly down-regulated from circulating T cells. These results suggest that intraperitoneal free MC have immunomodulatory functions through the control of l-arginine level, and thus may play significant roles in the pathogenesis of various diseases in the peritoneal cavity.