IL18 and infection: To address this, we infected conventional IL-23p19−/−, IL-22−/−, IL-18−/− and corresponding wildtype (WT) mice perorally with C. jejuni strain ATCC 43431 and investigated (1) the gastrointestinal colonization and translocation properties of C. jejuni as well as of commensal E. coli facilitating pathogenic infection, (2) the clinical outcome, (3) the subsequent apoptotic changes of the colon epithelium, (4) the abundances of distinct immune cell populations in the colonic mucosa and lamina propria, and finally (5) the large intestinal expression of inflammatory and regulatory cytokines.