Neutralization epitope of the varicella-zoster virus gH:gL glycoprotein complex

Varicella-zoster virus (VZV) glycoprotein gpIII is the homolog of herpes simplex virus gH. Through the use of panels of monoclonal antibodies, VZV gpIII is known to possess a complement-independent neutralization epitope which is conformational in nature. Monoclonal antibody to this same epitope, when added postinfection, inhibits both syncytia formation and egress of virus. The nature of the neutralization epitope was investigated to determine whether its formation was dependent on gpIII alone or required a second VZV glycoprotein. To this end, VZV ORF 37 (gH) and VZV ORF 60 (gL homolog) were cloned into a vaccinia virus-pTM1 expression system. Analyses of the transfected products demonstrated that gpIII alone was not fully glycosylated nor was it transported to the cell surface. When both ORF 37 and ORF 60 were cotransfected, the gpIII product was transported to the cell surface, where it formed a neutralization epitope recognized by a previously characterized monoclonal antibody reagent. In summary, the VZV homologs of the herpes simplex virus gH:gL complex included a M(r) 118,000 product (gpIII or gH) and a M(r) 20,000 product (ORF 60 or gL).