Recombinant nucleocapsid protein-based IgG enzyme-linked immunosorbent assay for the serological diagnosis of SARS

J Virol Methods. 2005 May;125(2):181-6. doi: 10.1016/j.jviromet.2005.01.028.


The recombinant nucleocapsid protein (rNP) of severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) was expressed in a baculovirus system. The purified SARS-CoV rNP was used as an antigen for detection of SARS-CoV antibodies in IgG enzyme-linked immunosorbent assay (ELISA). The ELISA was evaluated in comparison with neutralizing antibody assay and the authentic SARS-CoV antigen-based IgG ELISA. Two-hundred and seventy-six serum samples were collected from health care workers in a hospital in which a nosocomial SARS outbreak took place and used for evaluation. The SARS-CoV rNP-based IgG ELISA has 92% of sensitivity and specificity compared with the neutralizing antibody assay and 94% sensitivity and specificity compared with the authentic SARS-CoV antigen-based IgG ELISA. The results suggest that the newly developed SARS-CoV rNP-based IgG ELISA is a valuable tool for the diagnosis and seroepidemiological study of SARS. The SARS-CoV rNP-based IgG ELISA has an advantage over the conventional IgG ELISA in that the antigen can be prepared by laboratory workers without the risk of infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Viral*
  • Chlorocebus aethiops
  • Coronavirus Nucleocapsid Proteins
  • Enzyme-Linked Immunosorbent Assay / methods*
  • Immunoglobulin G / blood
  • Nucleocapsid Proteins / immunology*
  • Recombinant Proteins / immunology
  • SARS Virus / immunology
  • SARS Virus / isolation & purification*
  • Severe Acute Respiratory Syndrome / diagnosis*
  • Severe Acute Respiratory Syndrome / immunology
  • Vero Cells


  • Antibodies, Viral
  • Coronavirus Nucleocapsid Proteins
  • Immunoglobulin G
  • Nucleocapsid Proteins
  • Recombinant Proteins