Endogenous C-type viral expression in primates

Abstract

C-TYPE viruses are genetically transmitted in species representing several orders of vertebrates (for review see refs 1 and 2). So far the isolation of endogenous viruses of primates has been limited to species of Papio3–5 although related viral nucleic acid sequences have been detected in cellular DNAs of several other Old World monkeys6. The extent of divergence of known endogenous primate viruses should be useful in predicting properties of the gene products of evolutionary related endogenous viruses of primates from which such viruses have yet to be isolated. We report here an investigation of the antigenic divergence of different structural proteins of prototype endogenous primate C-type virus isolates. Endogenous viral antigen expression was also examined in tissues of primate species, representing the major genera of the order Anthropoidea. Immunologically divergent gene products of endogenous viruses were found to be expressed in tissues of Old World monkeys, including many species that have not yet yielded complete virus. These findings, together with the marked variations in viral antigen expression demonstrated among different primate genera, have implications for endogenous virus regulation in primates and the search for related viruses of humans.