Effect of 7,12-Dimethylbenz[a]anthracene on Production and Action of Gamma Interferon

Spleens were removed from Swiss Webster mice, and cultures of spleen cells were prepared. Gamma (type II immune) interferon (IFN) production was induced in these cells by addition of the purified protein form of phytohemagglutinin (PHA-P) to the cultures. When 7,12-dimethylbenz[a]anthracene (DMBA) was added to the cultures either before or after addition of PHA-P, the production of gamma IFN was inhibited. The degree of inhibition was greater when the cells were treated with DMBA before addition of PHA-P. In experiments to determine the effects of DMBA on the antivirus activity of previously prepared gamma IFN preparations, DMBA was either added to target cells before the addition of exogenous gamma IFN or mixed together with exogenous gamma IFN. In both cases, the antivirus activity of this exogenous gamma IFN was not affected. These data suggest that DMBA treatment can inhibit the production but not the antivirus activity of murine gamma IFN.