Blocking antibody access to neutralizing domains on glycoproteins involved in entry as a novel mechanism of immune evasion by herpes simplex virus type 1 glycoproteins C and E

J Virol. 2008 Jul;82(14):6935-41. doi: 10.1128/JVI.02599-07. Epub 2008 May 14.

Abstract

Herpes simplex virus type 1 (HSV-1) glycoprotein C (gC) blocks complement activation, and glycoprotein E (gE) interferes with IgG Fc-mediated activities. While evaluating gC- and gE-mediated immune evasion in human immunodeficiency virus (HIV)-HSV-1-coinfected subjects, we noted that antibody alone was more effective at neutralizing a strain with mutations in gC and gE (gC/gE) than a wild-type (WT) virus. This result was unexpected since gC and gE are postulated to interfere with complement-mediated neutralization. We used pooled human immunoglobulin G (IgG) from HIV-negative donors to confirm the results and evaluated mechanisms of the enhanced antibody neutralization. We demonstrated that differences in antibody neutralization cannot be attributed to the concentrations of HSV-1 glycoproteins on the two viruses or to the absence of an IgG Fc receptor on the gC/gE mutant virus or to enhanced neutralization of the mutant virus by antibodies that target only gB, gD, or gH/gL, which are the glycoproteins involved in virus entry. Since sera from HIV-infected subjects and pooled human IgG contain antibodies against multiple glycoproteins, we determined whether differences in neutralization become apparent when antibodies to gB, gD, or gH/gL are used in combination. Neutralization of the gC/gE mutant was greatly increased compared that of WT virus when any two of the antibodies against gB, gD, or gH/gL were used in combination. These results suggest that gC and gE on WT virus provide a shield against neutralizing antibodies that interfere with gB-gD, gB-gH/gL, or gD-gH/gL interactions and that one function of virus neutralization is to prevent interactions between these glycoproteins.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antibodies, Viral / immunology*
  • Antibodies, Viral / metabolism*
  • Chlorocebus aethiops
  • Epitopes / immunology
  • Herpesvirus 1, Human / immunology*
  • Humans
  • Immunoglobulin G / immunology
  • Immunoglobulin G / metabolism
  • Neutralization Tests
  • Protein Binding
  • Vero Cells
  • Viral Envelope Proteins / immunology*
  • Viral Envelope Proteins / metabolism

Substances

  • Antibodies, Viral
  • Epitopes
  • Immunoglobulin G
  • Viral Envelope Proteins
  • glycoprotein E, herpes simplex virus type 1
  • glycoprotein gC, herpes simplex virus type 1