IL6 and infection: Following WT strain infection only, colonic levels of IL-6 and IFN-γ were elevated (p < 0.01 and p < 0.001, respectively; Fig. 6b, d), which also held true for nitric oxide and IFN-γ concentrations in ex vivo biopsies derived from mesenteric lymph nodes (MLN) at day 6 p.i. (p < 0.001 and p < 0.01, respectively; Fig. 6e, f).