RT Journal Article SR Electronic T1 Protective effects of Fc-fused PD-L1 on two different animal models of colitis JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 260 OP 271 DO 10.1136/gutjnl-2014-307311 VO 64 IS 2 A1 Mi-Young Song A1 Chun-Pyo Hong A1 Seong Jeong Park A1 Jung-Hwan Kim A1 Bo-Gie Yang A1 Yunji Park A1 Sae Won Kim A1 Kwang Soon Kim A1 Ji Yeung Lee A1 Seung-Woo Lee A1 Myoung Ho Jang A1 Young-Chul Sung YR 2015 UL http://gut.bmj.com/content/64/2/260.abstract AB Objective Programmed death-ligand 1 (PD-L1) has been shown to negatively regulate immune responses via its interaction with PD-1 receptor. In this study, we investigated the effects of PD-L1-Fc treatment on intestinal inflammation using two murine models of inflammatory colitis induced by dextran sulfate sodium (DSS) and T-cell transfer. Design The anti-colitis effect of adenovirus expressing Fc-conjugated PD-L1 (Ad/PD-L1-Fc) and recombinant PD-L1-Fc protein was evaluated in DSS-treated wild-type and Rag-1 knockout (KO) mice. We examined differentiation of T-helper cells, frequency of innate immune cells, and cytokine production by dendritic cells (DCs) in the colon from DSS-treated mice after PD-L1-Fc administration. In Rag-1 KO mice reconstituted with CD4 CD45RBhigh T cells, we assessed the treatment effect of PD-L1-Fc protein on the development of colitis. Results Administration of Ad/PD-L1-Fc significantly ameliorated DSS-induced colitis, which was accompanied by diminished frequency of interleukin (IL)-17A-producing CD4 T cells and increased interferon-γ-producing CD4 T cells in the colon of DSS-fed mice. The anti-colitic effect of PD-L1-Fc treatment was also observed in DSS-treated Rag-1 KO mice, indicating lymphoid cell independency. PD-L1-Fc modulated cytokine production by colonic DCs and the effect was dependent on PD-1 expression. Furthermore, PD-L1-Fc protein could significantly reduce the severity of colitis in CD4 CD45RBhigh T-cell-transferred Rag-1 KO mice. Conclusions Based on the protective effect of PD-L1-Fc against DSS-induced and T-cell-induced colitis, our results suggest that PD-1-mediated inhibitory signals have a crucial role in limiting the development of colonic inflammation. This implicates that PD-L1-Fc may provide a novel therapeutic approach to treat inflammatory bowel disease.