THE IN-VIVO ANTIVIRAL ACTIVITY OF INTERLEUKIN-12 IS MEDIATED BY GAMMA-INTERFERON

The injection of 20 ng of mouse interleukin-12 (IL-12) protects mice f rom a lethal infection with encephalomyocarditis virus. In vitro, an a nti-gamma interferon (anti-IFN-gamma) monoclonal antibody but not an a nti-IL-12 monoclonal antibody neutralizes the antiviral activity prese nt in the supernatants of splenocytes stimulated with IL-12. Finally, IL-12 fails to protect 129 Sv/Ev IFN-gamma R(0/0) mice against encepha lomyocarditis virus infection. These results demonstrate that IL-12 ex erts its antiviral activity through the induction of endogenous IFN-(g )amma.