IL17A and colitis: Immunostaining of colon sections with specific antibodies revealed elevated numbers of infiltrating neutrophils, macrophages, and DCs in colons of mice with DSS-induced colitis compared with normal control group, which was accompanied by enhanced expressions of several inflammatory cytokines and chemokines including S100a9, Tnfα, Il1β, Ifnγ, Il6, Il17a, Il23a, Il4, and Il12a, but these effects were repressed by anti-S100a9 Ab treatment (Figures 3B,C).