AHR and infection: To investigate AhR-mediated pharmacological modulation during IBV infection, Vero and H1299 cell cultures were treated with dimethyl sulfoxide (vehicle), CH223191 (2.5 μM, 5 μM, 10 μM, and 20 μM), or kynurenine (5 μM, 10 μM, 20 μM, and 40 μM), administered during pre- and post-infection phases.