P155 THERAPEUTIC EFFECT OF OPS-2071 ON HEALING OF T CELL-MEDIATED COLITIS, A MURINE MODEL OF CROHN’S DISEASE, WITH ANTI-INFLAMMATORY AND ANTIBACTERIAL ACTIVITY

Abstract Background Crohn’s disease (CD) is a form of chronic inflammatory bowel disease (IBD). Although CD is an immune-mediated condition of unknown etiology, many studies suggested that abnormal immune responses against certain intestinal bacteria may trigger development of chronic inflammation. The T cell-mediated colitis model is a well characterized adaptive transfer murine model of chronic small bowel and colonic inflammation that resembles human CD (e.g., diarrhea, a heavily inflamed colon, loss of mucus from goblet cells, Th1/Th17 dominated cytokine profile). OPS-2071, a novel agent synthesized by Otsuka Pharmaceutical Co., Ltd, has broad and strong antibacterial activity with low systemic absorption. In this study, we have evaluated the therapeutic effect of OPS-2071 on murine T cell-mediated colitis and in vitro activity on T cell activation, cytokine production and antibacterial activity. Methods T cell-mediated colitis was induced via naive T cell (CD4+CD62L+CD44-) injection into T and B cell deficient recipient mice. Two weeks following T cell transfer, OPS-2071 or vehicle solution was administered orally for 3 weeks, followed by harvesting of colon tissue and assessment of efficacy evaluation by histological score and inflammatory index (colon weight/ length). In vitro inhibitory action for TNF-α production was assayed by ELISA using LPS-stimulated human peripheral blood cells. The effect on T cell activation and cytokine production (TNF-α, IFN-γ), was examined using human peripheral blood mononuclear cells and, mouse spleen which were stimulated by anti-CD2/CD3/CD28 antibody-loaded beads. In vitro activity against bacteria considered to be the cause of IBD was also tested. Results In the murine T cell transfer model, OPS-2071 significantly reduced both histological score (control: 9.2, OPS: 2.7, p