AHR and immune system toxicity: Moreover, for CDE 77, 101, 118, 126, 153 and 156, an excellent linear correlation was observed between their immunotoxicity and induced ethoxyresorufin-O-deethylase (EROD) or aryl hydrocarbon hydroxylase (AHH) activity as markers of AHR activation in mice (Mus musculus) [56].