Studies on glycoproteins of varicella-zoster virus and their biological functions.

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Varicella-zoster virus (VZV) contains four major glycoproteins designated as gpI,gpII,gpIII and gpIV. Firstly, the presence and role of fatty acids in these glycoproteins were examined. The incorporation of fatty acid into the glycoproteins that span the membranes of VZV was studied using infected cells labeled with [^3H]-palmitic acid. An extract of the cells was treated with monoclonal antibodies to VZV glycoproteins and the precipitate was analyzed by sodium-dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The electrophoretic pattern showed that gpI was heavily labeled, and gpII and IV were lightly labeled. Cerulenin, an antibiotic that inhibits de novo fatty acid biosynthesis, was used to examine the effects of fatty acids on replication of VZV and posttranslational processing of glycoproteins. Treatment of the cells with cerulenin significantly inhibited viral growth, but did not affect protein synthesis in the cells. Examination of processing of viral glycoproteins … More in treated cells revealed the accumulation of the precursor proteins, and decrease in the amount of mature glycoproteins. these data suggest that fatty acid acylation of VZV glycoproteins is necessary for formation of complete infectious virions. Next, plasmid DNAs encoding gpI,gpII, gpIII and gpIV were inseted into vaccinia virus DNA and the recombinant viruses were used for immunological analysis. In consequence, the gpI derived from cells infected with virus showed have very similar antigenic characteristics as gpI derived from VZV infected cells by immunoprecipitation pattern, and antibody produced in rabbits infected with recombinant virus had high neutralizing activity, when the reaction was performed with complement. However, no virus specific polypeptides were detected in cells infected with other recombinant viruses, although RNAs were detected in infected cells. This result suggested that gpI has important role for protection and recovery from VZV infection. Finally, specificity of the skin test with VZV glycoprotein was examined in guinea pigs infected with herpes simplex virus(HSV) type 1 and VZV and in children with a history of HSV infection who developed varicella. No cross-reaction between HSV and VZV was detected and the skin test was specific for immunity to VZV infection in children. These results suggested that VZV skin test is specific for immunity to VZV infection. This specificity will be of value in screening or immunity to VZV, irrespective of prior HSV infection. Less