Enveloped virus-like particle expression of human cytomegalovirus glycoprotein B antigen induces antibodies with potent and broad neutralizing activity

Clin Vaccine Immunol. 2014 Feb;21(2):174-80. doi: 10.1128/CVI.00662-13. Epub 2013 Dec 11.

Abstract

A prophylactic vaccine to prevent the congenital transmission of human cytomegalovirus (HCMV) in newborns and to reduce life-threatening disease in immunosuppressed recipients of HCMV-infected solid organ transplants is highly desirable. Neutralizing antibodies against HCMV confer significant protection against infection, and glycoprotein B (gB) is a major target of such neutralizing antibodies. However, one shortcoming of past HCMV vaccines may have been their failure to induce high-titer persistent neutralizing antibody responses that prevent the infection of epithelial cells. We used enveloped virus-like particles (eVLPs), in which particles were produced in cells after the expression of murine leukemia virus (MLV) viral matrix protein Gag, to express either full-length CMV gB (gB eVLPs) or the full extracellular domain of CMV gB fused with the transmembrane and cytoplasmic domains from vesicular stomatitis virus (VSV)-G protein (gB-G eVLPs). gB-G-expressing eVLPs induced potent neutralizing antibodies in mice with a much greater propensity toward epithelial cell-neutralizing activity than that induced with soluble recombinant gB protein. An analysis of gB antibody binding titers and T-helper cell responses demonstrated that high neutralizing antibody titers were not simply due to enhanced immunogenicity of the gB-G eVLPs. The cells transiently transfected with gB-G but not gB plasmid formed syncytia, consistent with a prefusion gB conformation like those of infected cells and viral particles. Two of the five gB-G eVLP-induced monoclonal antibodies we examined in detail had neutralizing activities, one of which possessed particularly potent epithelial cell-neutralizing activity. These data differentiate gB-G eVLPs from gB antigens used in the past and support their use in a CMV vaccine candidate with improved neutralizing activity against epithelial cell infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Neutralizing / blood*
  • Antibodies, Viral / blood*
  • Cytomegalovirus / immunology
  • Cytomegalovirus Infections / immunology
  • Cytomegalovirus Infections / prevention & control*
  • Cytomegalovirus Vaccines / genetics
  • Cytomegalovirus Vaccines / immunology*
  • Cytomegalovirus Vaccines / metabolism
  • Epithelial Cells / virology
  • Female
  • Mice
  • Mice, Inbred BALB C
  • Vaccines, Virus-Like Particle / administration & dosage
  • Vaccines, Virus-Like Particle / genetics
  • Vaccines, Virus-Like Particle / immunology*
  • Vaccines, Virus-Like Particle / metabolism
  • Viral Envelope Proteins / administration & dosage
  • Viral Envelope Proteins / genetics
  • Viral Envelope Proteins / immunology*
  • Viral Envelope Proteins / metabolism

Substances

  • Antibodies, Neutralizing
  • Antibodies, Viral
  • Cytomegalovirus Vaccines
  • Vaccines, Virus-Like Particle
  • Viral Envelope Proteins
  • glycoprotein B, Simplexvirus