Amelioration of Friend Virus Leukemia by Sequential Administration of Viral and Nonviral Interferon Inducers

This study was designed to test the effect of the sequential administration of a series of viral and nonviral inducers of interferon on the progression of Friend virus leukemia in DBA/2 mice. The inducers, Poly I:C, SV, statolon, and tilorone hydrochloride, were given at 6-day intervals following injection of Friend virus, beginning 7 days postinfection until the 25th day. Mean splenomegaly, hepatomegaly, virus titer, and interferon titer were monitored periodically during the treatment regimen. Mice dying from the leukemia were autopsied and their liver and spleen weights recorded. The treatment regimen used was successful in increasing mean survival time and in decreasing hepatomegaly and splenomegaly. Decreases in virus titer and splenomegaly were associated with increased interferon levels in the spleens of experimental animals following administration of Poly I:C, statolon, and tilorone hydrochloride, while an enhancement phenomenon was observed after inoculation of SV. The amelioration of established Friend's disease observed using this program of therapy seems to offer promise, but other combinations of inducers (viral and nonviral) and protracted periods of treatment must be explored.