Diagnostic Potential of a Luminex-Based Coronavirus Disease 2019 Suspension Immunoassay (COVID-19 SIA) for the Detection of Antibodies against SARS-CoV-2

• Published in: Viruses Vol. 13; no. 6; p. 993
• Main Authors: Hoffman, Tove, Kolstad, Linda, Lindahl, Johanna F., Albinsson, Bo, Bergqvist, Anders, Rönnberg, Bengt, Lundkvist, Åke
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 26.05.2021; MDPI
• Subjects: Antibodies; Antigens; Asymptomatic; Bacterial infections; Blood donors; Coronavirus; Coronaviruses; COVID-19; Encephalitis; Enzyme immunoassay; Enzymes; Epstein-Barr virus; Genes; IgG; IgM; Immunoassay; Immunoglobulin G; Immunoglobulin M; Immunoglobulins; Infections; Insect cells; Middle East respiratory syndrome; Pandemics; Proteins; Reproducibility; Respiratory diseases; SARS-CoV-2; Serology; Severe acute respiratory syndrome coronavirus 2; Thermal cycling; United Kingdom > UK; United States > US; China; Germany
• ISSN: 1999-4915; 1999-4915
• DOI: 10.3390/v13060993

Due to the current, rapidly increasing Coronavirus disease 2019 (COVID-19) pandemic, efficient and highly specific diagnostic methods are needed. The receptor-binding part of the spike (S) protein, S1, has been suggested to be highly virus-specific; it does not cross-react with antibodies against other coronaviruses. Three recombinant partial S proteins of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) expressed in mammalian or baculovirus-insect cells were evaluated as antigens in a Luminex-based suspension immunoassay (SIA). The best performing antigen (S1; amino acids 16-685) was selected and further evaluated by serum samples from 76 Swedish patients or convalescents with COVID-19 (previously PCR and/or serologically confirmed), 200 pre-COVID-19 individuals (180 blood donors and 20 infants), and 10 patients with acute Epstein-Barr virus infection. All 76 positive samples showed detectable antibodies to S1, while none of the 210 negative controls gave a false positive antibody reaction. We further compared the COVID-19 SIA with a commercially available enzyme immunoassay and a previously evaluated COVID-19 rapid antibody test. The results revealed an overall assay sensitivity of 100%, a specificity of 100% for both IgM and IgG, a quantitative ability at concentrations up to 25 BAU/mL, and a better performance as compared to the commercial assays, suggesting the COVID-19 SIA as a most valuable tool for efficient laboratory-based serology.