Suppression of T lymphocyte proliferation to antigenic and mitogenic stimuli by Benzo(alpha)pyrene and 2-aminofluorene metabolites.

Here, we attempt to reveal how 2-aminofluorene (AF), benzo(alpha)pyrene (BP) and their major metabolites affect T-cell responses to antigenic and mitogenic stimuli. P-450-related metabolism of these parent compounds to metabolites seems to precede the observed immunosuppression; therefore, we investigated the influence of alpha-naphthoflavone (P-450 inhibitor) and beta-naphthoflavone (P-450 inducer) on BP and AF immunosuppression. We used proliferative responses to concanavalin A and the allogeneic mixed lymphocyte response as correlates of immunosuppression. We also attempted to correlate DNA-adduction to the extent of observed immunosuppression for AF and BP metabolites. These data show that the pathway to the strongest immunosuppressive agents for polycyclic aromatic hydrocarbons and arylamines are divergent and related to metabolism by P450 enzymes.