Depression of hepatic biotransformations by chemical immunoadjuvants.

Administration of BCG and Corynebacterium parvum is known to cause depression of the hepatic microsomal enzyme system (HMES) in mice. In the present study we explored the effects on HMES of two chemical immunoadjuvants, one of which (pyran copolymer) with peculiarly long-lasting biological activities. The two synthetic immunoadjuvants proved to be potent HMES inhibitors and, for pyran copolymer, peak levels of inhibition concurred with maximal macrophage activation. The inhibition was largely dose-dependent and could not be prevented by immunopharmacologic maneuvers that are known to block the C. parvum effect on HMES. The possibility is discussed that common mechanism(s) underlie the depression of HMES by immunoactive substances of both bacterial and chemical origin.