Cytokine that plays a crucial role in innate immunity of the epithelium, including to intestinal bacterial pathogens, in an autocrine manner. Stimulates the production of antibacterial peptides and pro-inflammatory molecules for host defense by signaling through the NFKB and MAPK pathways. Acts synergically with IL22, TNF and IL1B in inducing antibacterial peptides. May have protective function by maintaining epithelial homeostasis after an inflammatory challenge, such as that caused in the intestine by dextran sulfate sodium in a colitis model. May also promote an inflammatory phenotype, such as skin in a psoriasis model. Enhanced IL17C/IL17RE signaling may also lead to greater susceptibility to autoimmune diseases, such as autoimmune encephalitis. Binds to a heterodimer formed by IL17RA and IL17RE. Expressed by epithelial cells after bacterial challenge. Low expression, if any, in lymphocytes. Up-regulated in the colon, but not in spleen or liver, during infection with Citrobacter rodentium. Up-regulated by various inflammatory cytokines, including TNF, IL1B, IL17A and IL17F in colon epithelial cells. Mutant animals develop normally and do not exhibit any pronounced immunological deficiency. Belongs to the IL-17 family. Truncated N-terminus.