IL17A and Chronic colitis: The cytokine production profile observed in tissues with chronic colitis again showed increased expression of IFN-γ and IL-17 in CD200R1KO and CD200KO mice compared with either CD200tg or WT mice (Fig 6A–6C), consistent with reports on the role of IFN-γ and IL-17 in DSS-induced chronic colitis in mice [31,50].