Interferon independence of genetically controlled resistance to flaviviruses.

Flavivirus-resistant C3H/RV mice injected with sheep anti-interferon globulin and then infected with either West Nile or yellow fever virus survived and displayed no disease symptoms. Also, treatment of embryo fibroblast cultures prepared from C3H/RV or congenic susceptible C3H/HE mice with anti-interferon serum resulted in an increased yield of West Nile virus from both types of cultures, but the amount of infectious virus produced by resistant cultures remained 1 to 1.5 logs lower than that produced by susceptible cell cultures. These results indicate that the mode of expression of the flavivirus resistance gene differs significantly from that of the Mx gene conferring resistance to influenza virus-induced disease in A2G mice.