Recently, we reported that infection of mice with a C. rodentium mutant lacking the effector EspO (ΔespO) results in significantly higher bacterial load from 14 DPI compared to infection with wild type (WT) C. rodentium, which concur with reduced levels of colonic CD4+ T cells and C. rodentium-specific serum IgG antibodies [23]. The gene discussed is CD4; the disease is infection.