Simian varicella virus: characterization of virion and infected cell polypeptides and the antigenic cross-reactivity with varicella-zoster virus.

Simian varicella virus (SVV) causes a varicella-like disease in non-human primates. In this study, SVV virions were purified from SVV-infected BSC-1 cells by zonal and differential gradient centrifugation and the virion polypeptide composition was analysed by SDS-PAGE. SVV virions had a buoyant density of 1.21 g/ml, identical to the value obtained for varicella-zoster virus (VZV) virions purified by the same method. Electron microscopy of the concentrated SVV virions revealed characteristic herpesvirus morphology. SVV virions consisted of at least 30 polypeptide species ranging from 16K to greater than 200K. The electrophoretic profiles of radiolabelled SVV and VZV virion polypeptides were very similar. Immunoprecipitations of solubilized SVV-infected cell preparations using SVV immune sera revealed at least 18 viral polypeptides with an Mr range of 12K to 142K and six glycoproteins ranging from 46K to 115K. In addition, extensive cross-reactivity between SVV and VZV proteins and glycoproteins was demonstrated by immunoprecipitation with heterologous immune sera. The high degree of antigenic relatedness between SVV and VZV provides further support for simian varicella as a model for VZV infections.