This mimics human IBD as shown in several mouse models where Hh elicits spontaneous colitis.16–18,20,57 Although all of our conventionally housed mice were positive for the Helicobacter genus, only control mice remained consistently positive for Hh. In contrast, young DC-LMP1/CD40 mice showed already reduced prevalence, while Hh was hardly detectable in older DC-LMP1/CD40 mice. Here, CD40 is linked to colitis.