P107 IL10 secretion endows intestinal human iNKT cells with regulatory functions towards pathogenic T lymphocytes in Crohn's disease patients
Burrello, C.(1);Strati, F.(1);Diaz-Basabe, A.(1);Lattanzi, G.(1);Lopez, G.(2);Trombetta, E.(3);Conforti, F.S.(4);Botti, F.(5);Vecchi, M.(4);Fantini, M.C.(6);Caprioli, F.(4);Facciotti, F.(1);
(1)European Institute of Oncology, Experimental Oncology, Milano, Italy;(2)IRCCS Ospedale Policlinico Ca' Granda, Pathology Unit, Milan, Italy;(3)IRCCS Ospedale Policlinico Ca' Granda, Flow Cytometry Service, Milan, Italy;(4)IRCCS Ospedale Policlinico Ca' Granda, Gastroenterology and Endoscopy Unit, Milan, Italy;(5)IRCCS Ospedale Policlinico Ca' Granda, Surgery Unit, Milan, Italy;(6)University of Cagliari, Medical Science and Public Health- Gastroenterology Unit, Cagliari, Italy;
Invariant Natural Killer T (iNKT) cells perform pleiotropic functions in different tissues by secreting a vast array of pro-inflammatory and cytotoxic molecules. However, the presence and function of human intestinal iNKT cells capable to secrete immunomodulatory molecules such as IL-10 has never been reported so far. Here we describe for the first time the presence of IL10-producing iNKT cells (NKT10 cells) in the intestinal lamina propria of healthy individuals and of Crohn’s Disease (CD) patients.
Frequency and phenotype of NKT10 cells were analyzed ex-vivo from intestinal specimens of Crohn’s disease (n=17) and controls (n=7). Stable CD-derived intestinal NKT10 cell lines were used to perform in vitro suppression assays and cocultures with patients'-derived mucosa-associated microbiota. Experimental colitis models were performed by adoptive cell transfer of murine splenic naïve CD4+ T cells in the presence or absence of IL10-sufficient or deficient iNKT cells. In vivo induction of NKT10 cells was performed by administration of SCFA by oral gavage.
Patient’s derived intestinal NKT10 cells demonstrated suppressive capabilities towards pathogenic CD4+ T cells. The presence of increased proportions of mucosal NKT10 cells associated with better clinical outcomes in CD patients. Moreover, an intestinal microbial community enriched in SCFA-producing bacteria sustained the production of IL10 by iNKT cells. Finally, IL10- deficient iNKT cells failed to control the pathogenic activity of adoptively transferred CD4+ T cells in an experimental colitis model.
These results describe an unprecedent IL10-mediated immunoregulatory role of intestinal iNKT cells in controlling the pathogenic functions of mucosal T-helper subsets and in maintaining the intestinal immune homeostasis.