IL18 and infection: Six days following C. jejuni strain 81–176 infection, colonic numbers of both innate and adaptive immune cell subsets such as neutrophils, T and B lymphocytes were lower in IL-23p19-/-, IL-22-/- and IL-18-/- as compared to WT infant mice, whereas large intestinal Treg numbers were lower in infected IL-23p19-/- and IL-22-/- versus WT infant control animals [39].