Effect of in vivo administration of the carcinogen benzo(a)pyrene on interleukin-2 and interleukin-3 production.

B6C3F1 mice were exposed to the environmental carcinogen benzo(a)pyrene, a well known immunosuppressant. The ability of isolated splenocytes to produce and respond to the immunoregulatory molecules interleukin-2 (IL-2) and interleukin-3 (IL-3) was measured. Significant suppression by BaP of IL-2, but not IL-3, production following BaP exposure was observed. Further, exogenous recombinant IL-2 reconstituted the ability of splenocytes from benzo(a)pyrene treated mice to generate IgM antibody producing cells to the T-dependent antigens of sheep red blood cells. These results indicate that one of the cellular target(s) of BaP induced immunosuppression may be the mechanism(s) responsible for lymphokine production and regulation by activated T cells.