Virus particles and glycoprotein excreted from cultured cells infected with varicella-zoster virus (VZV)

Abstract

Virus particles and virus proteins excreted from cultured human embryonic lung (HEL) cells infected with varicella-zoster virus (VZV) were examined by electron microscopy and affinity column chromatography using an antibody to VZV followed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Approximately 1 X 10(9) to 2 X 10(9) virus particles/ml with no detectable infectivity, of which 30 to 80% were enveloped, were observed in the culture fluid 48 to 72 h after infection, when cytopathic effect (c.p.e.) appeared. In the sonicated infected cell suspension, 1 X 10(9) to 2 X 10(9) virus particles/ml, of which 30 to 50% were enveloped, were observed and the virus particle/infectivity ratio was approx. 10(6):1. The culture fluid of infected HEL cells labelled with [35S]methionine or [3H]glucosamine was centrifuged at 1000000 g for 2 h to remove virus particles and the supernatant was examined for excreted virus proteins. Affinity column chromatography of the supernatant using immobilized human zoster convalescent serum, led to the isolation of virus antigens which were analyzed by SDS-PAGE. Polypeptides with mol. wt. of approx. 115K and 45K, both of which were glycosylated, were detected, suggesting that these VZV glycoproteins were excreted from the infected cells.