ANALYSIS OF EARLY AND LATE EPSTEIN-BARR VIRUS ASSOCIATED POLYPEPTIDES BY IMMUNOPRECIPITATION

The Epstein-Barr virus-producing cell lines P3HR-1 and B95-8 and the nonproducer cell lines Raji clone No. 7 and NC37 were induced to viral antigen synthesis by the tumor promoter TPA and then analyzed by immunoprecipitation with human sera for early and late virus-associated polypeptides. After labeling of producer cells for a 4-day period with [35S]methionine, two polypeptides with molecular weights of 140,000 and 150,000 were identified reacting predominately with virus capsid antigen (VCA+) sera. Analysis of purified Epstein-Barr virus demonstrated that the 140,000 polypeptide presumably represents an envelope protein while the 150,000 polypeptide is a nucleocapsid protein. In 4-hr radioactively labeled producer cells an additional polypeptide with a molecular weight of 130,000 was found to be immunoreactive with VCA+ sera. Immunoprecipitation of [35S]methionine-labeled cell extracts from nonproducer cells resulted in the specific precipitation of two polypeptides with molecular weights of 85,000 and 35,000 which most likely represent early EBV-associated proteins. Producer cells exhibit three additional apparently early EBV-associated polypeptides with molecular weights of 120,000, 18,000, and 16,000. None of these polypeptides could be detected in EBV genome-negative Ramos cells after TPA treatment. © 1979.