The manner in which interferon treatment results in antiviral, anticellular, antitumor, immunomodulatory, and many other effects is not understood. We plan to identify and characterize the proteins which are induced in various mouse and human cells upon interferon treatment. Cells will be labelled with radioactive amino acids during interferon treatment, and their extracts will be fractionated by various techniques such as ammonium sulfate fractionation, ion-exchange chromatography, gel filtration, chromatography on double-stranded RNA columns, etc., and various fractions will be analyzed by SDS-polyacrylamide gel electrophoresis in slab gels to identify induced proteins. In such studies, we have already detected certain proteins that are induced in mouse cells (Ehrlich ascites, L929) and in human cells (FS4, GM258) upon treatment with homologous interferon. We suspect that these proteins may be the products of the cellular genetic information that is required to be induced for the development of the antiviral effect of interferon. We plan to investigate the association of these induced proteins with the biological effects of interferon using the antiviral effect as a criterion, and to examine their possible correlation with the known interferon-induced enzymes (a protein kinase and 2'-5' oligoadenylate synthetase) and the kinetics of their induction during interferon treatment and de-induction upon withdrawal of interferon. We also plan to raise antibodies against several of these induced proteins for future studies on the induction process.