Serological profiles of pan-coronavirus-specific responses in COVID-19 patients using a multiplexed electro-chemiluminescence-based testing platform

PLoS One. 2021 Jun 3;16(6):e0252628. doi: 10.1371/journal.pone.0252628. eCollection 2021.


Serological assessment of SARS-CoV-2 specific responses are an essential tool for determining the prevalence of past SARS-CoV-2 infections in the population especially when testing occurs after symptoms have developed and limited contact tracing is in place. The goal of our study was to test a new 10-plex electro-chemiluminescence-based assay to measure IgM and IgG responses to the spike proteins from multiple human coronaviruses including SARS-CoV-2, assess the epitope specificity of the SARS-CoV-2 antibody response against full-length spike protein, receptor-binding domain and N-terminal domain of the spike protein, and the nucleocapsid protein. We carried out the assay on samples collected from three sample groups: subjects diagnosed with COVID-19 from the U.S. Army hospital at Camp Humphreys in Pyeongtaek, South Korea; healthcare administrators from the same hospital but with no reported diagnosis of COVID-19; and pre-pandemic samples. We found that the new CoV-specific multiplex assay was highly sensitive allowing plasma samples to be diluted 1:30,000 with a robust signal. The reactivity of IgG responses to SARS-CoV-2 nucleocapsid protein and IgM responses to SARS-CoV-2 spike protein could distinguish COVID-19 samples from non-COVID-19 and pre-pandemic samples. The data from the three sample groups also revealed a unique pattern of cross-reactivity between SARS-CoV-2 and SARS-CoV-1, MERS-CoV, and seasonal coronaviruses HKU1 and OC43. Our findings show that the CoV-2 IgM response is highly specific while the CoV-2 IgG response is more cross-reactive across a range of human CoVs and also showed that IgM and IgG responses show distinct patterns of epitope specificity. In summary, this multiplex assay was able to distinguish samples by COVID-19 status and characterize distinct trends in terms of cross-reactivity and fine-specificity in antibody responses, underscoring its potential value in diagnostic or serosurveillance efforts.

Publication types

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

MeSH terms

  • Adult
  • Antibodies, Viral / analysis
  • Antibodies, Viral / immunology*
  • Antibody Formation
  • COVID-19 / immunology*
  • Cross Reactions
  • Female
  • Humans
  • Immunoglobulin G / analysis
  • Immunoglobulin G / immunology
  • Immunoglobulin M / analysis
  • Immunoglobulin M / immunology
  • Luminescence
  • Male
  • Middle Aged
  • Middle East Respiratory Syndrome Coronavirus / immunology
  • Military Personnel
  • Nucleocapsid Proteins / immunology
  • SARS-CoV-2 / immunology*
  • SARS-CoV-2 / pathogenicity
  • Sensitivity and Specificity
  • Severe acute respiratory syndrome-related coronavirus / immunology
  • Spike Glycoprotein, Coronavirus / immunology
  • United States


  • Antibodies, Viral
  • Immunoglobulin G
  • Immunoglobulin M
  • Nucleocapsid Proteins
  • Spike Glycoprotein, Coronavirus
  • spike protein, SARS-CoV-2

Grants and funding

The work was funded by the Military Infectious Disease Research program (MIDRP), which was not in the online database of funders. The funders did not have any influence on this study and the experimental plan.