IL21 and infection: In this study we discovered a previously unknown collaboration between IL-21 and IFN-γ inducing interferon-stimulated genes (ISGs), in the course of studies on the role of the IL-21/IL-21R signaling pathway in resistance to and clearance of infection with a minimally-invasive murine intestinal pathogen C. rodentium. Deficiency in this pathway leads to attenuated inflammation in the colon following infection with this pathogen and impaired clearance of the pathogen.