· Flagellin (ligand for TLR5 or NLRC4) is necessary to exacerbate DSS-induced mouse colitis · LF82 adhesion is mediated by binding of the type 1 pili of AIEC to the host glycoprotein CEACAM6 on IECs · Flagellin produced by AIEC is a key molecule that promotes the expression of IL1RL1 in IECs, which associates with intestinal fibrosis. Here, CEACAM6 is linked to colitis.