MYD88 and bacterial infectious disease: To elucidate the cellular basis for the significant impairment of host protective immunity against C. rodentium infection in helminth co-infected host, we examined the frequency and distribution of innate immune cells that are known to play an important role in mucosal defense against bacterial infection, specifically, macrophages and neutrophils, in the colonic tissue of MyD88 knockout mice with C. rodentium infection.