In order to determine if IL-33–mediated protection against reinfection was mediated by antibody, μMT-KO mice that lack mature B cells were pretreated with IL-33 and infected with C. difficile (Figure 3A) During the first 10 days of the initial C. difficile infection, there was no difference in weight loss or clinical scores between WT and μMT-KO mice, consistent with prior work that showed no role of B cells and T cells in the acute phase of CDI (Figure 3, B and C) (14, 17). Here, IL33 is linked to clostridium difficile infection.