CALCA and infection: The enhanced susceptibility to C. rodentium-infection and exacerbated intestinal injury in the co-infected mice was found to be associated with diminished innate immune responses to C. rodentium infection, as evidenced by the inhibition of anti-microbial peptide expression, the reduction of C. rodentium-induced expression of KC, and impaired neutrophil recruitment in the intestine (Figure 4, 5 and 7).