However, whole microbiota from mice on the AhR ligand-free diet were able to recapitulate the IgA-reducing, but not the AhR ligand consuming, effects of F. rodentium. Given the greater susceptibility of mice with low fecal IgA levels to chemically-induced colitis30,54, future work will determine if the AhR ligand-free diet makes mice more susceptible to DSS colitis and if the microbiota in general and F. rodentium in particular directly contribute to the higher susceptibility. Here, AHR is linked to colitis.