IL6 and infection: Furthermore, IFN-γ, nitric oxide (NO), and IL-6 levels measured in colonic ex vivo biopsies increased until day six following CCUG 30485 strain (p<0.05–0.0005; Fig 4B–4D), but not C1 strain infection, whereas at day 16 p.i. respective mediators were comparable to those observed in colons of uninfected mice (Fig 4B–4D).