Indeed, neutralization of IL-23 has been shown to ameliorate and cure colitis in a number of mouse models of IBD, including colitis induced by naive T cell transfer (Elson et al., 2007; Hue et al., 2006) in which the role for IL-23 has been linked to control of Th17 cell responses (Leppkes et al., 2009). This evidence concerns the gene IL23A and colitis.