Comparison of Interferon Induction in Mice by Purified Penicillium chrysogenum Virus and Derived Double-stranded RNA

Biochemistry Department, Imperial College of Science and Technology, London, S.W.7 A virus preparation, obtained from the mycelium of Penicillium chrysogenum , strain Q176, was purified by isopycnic centrifugation on linear gradients of potassium tartrate. Double-stranded RNA, prepared from the virus particles, revealed three components on electrophoresis on polyacrylamide gels. The serum interferon levels in mice after intravenous injection of free virus RNA were higher and earlier than for purified virus particles, containing an equivalent amount of RNA. After reaching their maxima, the interferon activities declined at similar rates to very low levels after 45 hr for free RNA and 39 hr for virus particles. Received 17 November 1970; accepted 29 March 1971.