FLG and coinfection: Non-motile R20291 fliC (flagellin), fliD (flagellar cap), or flgE (hook protein) mutants showed reduced adherence to Caco-2 intestinal epithelial cells in vitro, and in a co-infection with wildtype R20291, the fliC mutant colonized mice in fewer numbers.35 In the current study, the mouse model was more effective at revealing differences between flg-Δ3 ON and flg-Δ3 OFF.