Epitope mapping and biological function analysis of antibodies produced by immunization of mice with an inactivated Chinese isolate of severe acute respiratory syndrome-associated coronavirus (SARS-CoV)

Virology. 2005 Mar 30;334(1):134-43. doi: 10.1016/j.virol.2005.01.035.

Abstract

Inactivated severe acute respiratory syndrome-associated coronavirus (SARS-CoV) has been tested as a candidate vaccine against the re-emergence of SARS. In order to understand the efficacy and safety of this approach, it is important to know the antibody specificities generated with inactivated SARS-CoV. In the current study, a panel of twelve monoclonal antibodies (mAbs) was established by immunizing Balb/c mice with the inactivated BJ01 strain of SARS-CoV isolated from the lung tissue of a SARS-infected Chinese patient. These mAbs could recognize SARS-CoV-infected cells by immunofluorescence analysis (IFA). Seven of them were mapped to the specific segments of recombinant spike (S) protein: six on S1 subunit (aa 12-798) and one on S2 subunit (aa 797-1192). High neutralizing titers against SARS-CoV were detected with two mAbs (1A5 and 2C5) targeting at a subdomain of S protein (aa 310-535), consistent with the previous report that this segment of S protein contains the major neutralizing domain. Some of these S-specific mAbs were able to recognize cleaved products of S protein in SARS-CoV-infected Vero E6 cells. None of the remaining five mAbs could recognize either of the recombinant S, N, M, or E antigens by ELISA. This study demonstrated that the inactivated SARS-CoV was able to preserve the immunogenicity of S protein including its major neutralizing domain. The relative ease with which these mAbs were generated against SARS-CoV virions further supports that subunit vaccination with S constructs may also be able to protect animals and perhaps humans. It is somewhat unexpected that no N-specific mAbs were identified albeit anti-N IgG was easily identified in SARS-CoV-infected patients. The availability of this panel of mAbs also provided potentially useful agents with applications in therapy, diagnosis, and basic research of SARS-CoV.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antibodies, Monoclonal / biosynthesis
  • Antibodies, Viral / biosynthesis
  • Antigens, Viral / genetics
  • China
  • Chlorocebus aethiops
  • Epitope Mapping
  • Humans
  • Immunization
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / immunology
  • Mice
  • Mice, Inbred BALB C
  • Neutralization Tests
  • Rabbits
  • Severe acute respiratory syndrome-related coronavirus / genetics
  • Severe acute respiratory syndrome-related coronavirus / immunology*
  • Severe acute respiratory syndrome-related coronavirus / isolation & purification
  • Spike Glycoprotein, Coronavirus
  • Vaccines, Inactivated / immunology
  • Vero Cells
  • Viral Envelope Proteins / genetics
  • Viral Envelope Proteins / immunology
  • Viral Vaccines / immunology*

Substances

  • Antibodies, Monoclonal
  • Antibodies, Viral
  • Antigens, Viral
  • Membrane Glycoproteins
  • Spike Glycoprotein, Coronavirus
  • Vaccines, Inactivated
  • Viral Envelope Proteins
  • Viral Vaccines
  • spike glycoprotein, SARS-CoV
  • spike protein, mouse hepatitis virus