Herpesviruses have been implicated as etiological agents of some forms of animal and human cancers. This has raised the possibility of prevention of these cancers through the use of viral vaccines. Because of the potential danger of using attenuated or inactivated herpesviruses containing intact viral genetic information for the induction of immunity in human populations, it would appear to be more realistic to consider using purified viral proteins free of viral DNA for inducing a protective immune response against the oncogenic virus or the virus-induced transformed cell. This requires the purification and characterization of the appropriate viral antigens. In some of the herpesvirus systems, including Herpes simplex virus and Epstein-Barr virus, these antigens appear to be expressed in the membranes of infected cells. The major objectives of this research proposal are: 1) to continue the isolation and purification of membrane antigens induced by EBV and Herpesvirus saimiri, an oncogenic nonhuman primate virus; 2) to produce monospecific antisera against these components for utilization in studies directed at defining the relationship of MA to other virus-associated antigens; 3) to identify the EBV antigens expressed in infected or transformed cells that serve as targets for antibody dependent cellular cytotoxicity (ADCC); and 4) to assess the potential use of purified MA components as possible subviral vaccines for prevention of tumor induction by these 2 viruses in owl monkeys. Membrane fragments prepared by solubilization of virus-infected cells with Triton X-100 will serve as the main source of MA. Radioimmune precipitation will serve as the main assay for identifying viral-induced glycoproteins. Purification schemes will employ primarily immuno-affinity and lectin chromatography and preparative polyacrylamide gel electrophoresis.