Glycoprotein C of Herpes Simplex Virus Type 1 Prevents Complement-Mediated Cell Lysis and Virus Neutralization

Abstract

Glycoprotein gCl of herpes simplex virus type 1 (HSV-l) binds complement component C3b. To determine if gCl modifies the interaction of complement with virus-infected cells or cell-free virus, ns-l, a mutant HSV-l strain that does not express gCl at the cell surface and does not bind C3b, was compared with its parental strain, NS. Cells infected with the gCl mutant were more susceptible to cytolysis mediated by antibody and complement or complement alone. The gCl or gDl genes were expressed in mammalian cells under the control ofan inducible promoter. Cells induced to express gCl resisted complement cytolysis, while cells expressing gDl did not. gCl modified cytolysis of virus-infected or -transfected cells by blocking alternative complement pathway activation. gCl also modified complement-dependent virus neutralization, which was mediated by inhibiting the classical complement pathway. These results indicate a protective role for gCl on the virion and at the cell surface.