Production of Interferon in Embryonated Eggs and in Cell Cultures Infected with Simian Virus 5. ∗

Summary

SV5, a strain of parainfluenza 5, was adapted to grow in 7-8-day-old embryo-nated eggs. SV5 infected egg fluid proved to be capable of inhibiting the growth of Sindbis virus in CE tissue culture both under agar overlay and in fluid medium. The inhibitor substance was found to be acid resistant, sensitive to trypsin digestion, but could not be neutralized by specific SV5 antiserum, and was characterized as an interferon. The yield of SV5 interferon in embryonated eggs was dependent on the dosage of inoculum, and the days of virus growth in the embryonated eggs. Chick embryo cell cultures infected with SV5 or CE fibroblast cultures adsorbed with SV5 supernatant fluid from infected CE cells were resistant to plaque formation by Sindbis virus. SV5 infected CE culture fluid did not protect AG monkey cultures from superinfection with Sindbis virus. AG monkey cells infected with SV5 were resistant to super-infection with Sindbis virus, but these SV5 infected monkey cells did not interfere with the multiplication of poliovirus type 1. SV5 produces interferon in both avian and primate cell systems but the presence of SV5 interferon requires a highly sensitive test system.