Severe Acute Respiratory Syndrome Coronavirus 2-Specific Antibody Responses in Coronavirus Disease Patients

Emerg Infect Dis. 2020 Jul;26(7):1478-1488. doi: 10.3201/eid2607.200841. Epub 2020 Jun 21.

Abstract

A new coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has recently emerged to cause a human pandemic. Although molecular diagnostic tests were rapidly developed, serologic assays are still lacking, yet urgently needed. Validated serologic assays are needed for contact tracing, identifying the viral reservoir, and epidemiologic studies. We developed serologic assays for detection of SARS-CoV-2 neutralizing, spike protein-specific, and nucleocapsid-specific antibodies. Using serum samples from patients with PCR-confirmed SARS-CoV-2 infections, other coronaviruses, or other respiratory pathogenic infections, we validated and tested various antigens in different in-house and commercial ELISAs. We demonstrated that most PCR-confirmed SARS-CoV-2-infected persons seroconverted by 2 weeks after disease onset. We found that commercial S1 IgG or IgA ELISAs were of lower specificity, and sensitivity varied between the 2 assays; the IgA ELISA showed higher sensitivity. Overall, the validated assays described can be instrumental for detection of SARS-CoV-2-specific antibodies for diagnostic, seroepidemiologic, and vaccine evaluation studies.

Keywords: COVID-19; ELISA; HCoV; RBD; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; antibodies; coronavirus; coronavirus disease 2019; human coronavirus; neutralization; nucleocapsid protein; receptor-binding domain; respiratory infections; serologic analysis; spike protein; viruses; zoonoses.

MeSH terms

  • Antibodies, Viral / blood*
  • Betacoronavirus / immunology*
  • Clinical Laboratory Techniques / methods*
  • Coronavirus Infections / diagnosis*
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Neutralization Tests
  • Pandemics
  • Pneumonia, Viral / diagnosis*
  • Sensitivity and Specificity
  • Serologic Tests

Substances

  • Antibodies, Viral

Supplementary concepts

  • COVID-19
  • COVID-19 diagnostic testing
  • severe acute respiratory syndrome coronavirus 2