A virus inhibitor circulating in the blood of chickens, induced byFrancisella tularensis andListeria monocytogenes

Following the intravenous inoculation of chickens with large doses of livingFrancisella tularensis andListeria monocytogenes organisms, a virus inhibitor appeared in their serum. The first traces of the inhibitor were found four hours and the maximum levels eight and 24 hours after inoculation with a bacterial suspension. The administration of heat-inactivated microorganisms did not induced formation of the inhibitor. The dynamics of formation of the inhibitor and its properties resembled those of virus interferon.