In resistant mice (e.g., C57BL/6), CR causes a mild self-limiting infection, whereas susceptible mice (e.g., C3H/HeN and C57BL/6 Il22-/-) succumb to the infection.9–14 The CR infection cycle in C57BL/6 mice progresses through four distinct phases: Establishment (1–3 days post-infection [dpi]) – a small proportion of the inoculum colonizes the cecal lymphoid patch. This evidence concerns the gene IL22 and infection.