TNF and colitis: histopathological analysis of colon tissues revealed that IL17B alleviate the inflammatory cells infiltration and epithelial cells destruction in Il17b-/- colitis mice (Figures 3C, D)Further, treatment of IL17B significantly reduced TNF, IL1B, and IL6 expression in colon tissue in Il17b-/- colitic mice (Figure 3E).These data confirm that IL17B protects DSS-induced colitis.