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

Abstract

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.

Comparative evaluation of Luminex based assays for detection of SARS-CoV-2 antibodies in a transplantation laboratory

“…This indicates that Luminex technology is a suitable testing technique for SARS-CoV-2 antibody detection, however in this instance the assays provided a mildly decreased sensitivity than the control ELISA. This is in keeping with recent studies that have identified the use of individual Luminex assays can have comparable performance as compared to commercial ELISA assays ( Becker et al, 2021 ; Hoffman et al, 2021 ). However, to our knowledge, this is the first study providing a direct comparison of Luminex based assays for the detection of SARS-CoV-2 antibodies.…”

COVID‐19 seroprevalence and clinical picture in Swedish pediatric oncology and hematology patients

“…Sera were analyzed for wild‐type SARS‐CoV‐2 S1‐specific IgG and IgM antibodies using a COVID‐19 suspension immunoassay 17 . Briefly, S1 protein was coupled to carboxylated differentially color‐marked magnetic beads (MagPlex microspheres, Luminex Corp., TX, USA).…”

“…Sera were analyzed for wild‐type SARS‐CoV‐2 S1‐specific IgG and IgM antibodies using a COVID‐19 suspension immunoassay. 17 Briefly, S1 protein was coupled to carboxylated differentially color‐marked magnetic beads (MagPlex microspheres, Luminex Corp., TX, USA). For IgM determination, sera were pre‐incubated with GullSORB (Meridian Life Science, TN, USA) to remove IgG, mixed with PBS‐T (0.05% Tween‐20) and microsphere mixture to a final serum dilution of 1:50, then incubated with biotinylated anti‐human IgM (Sigma Aldrich, Merck, Darmstedt, Germany) or biotinylated protein G (Pierce Biotechnology, ThermoFisher Scientific, MA, USA), followed by addition of streptavidin–phycoerythrin (Invitrogen, ThermoFisher Scientific).…”

Acute and long-term immune responses to SARS-CoV-2 infection in unvaccinated children and young adults with inborn errors of immunity

“…Plates were read using a Luminex xMAP 100 analyzer; positive values were assigned with Median Fluorescent Intensity (MFI) ratio 2 SD higher to a serum pool from pre-COVID pandemic samples; value ≥1 was considered to be positive. Sensitivity more than 10 days after onset of COVID-19 symptoms was 97% for IgG and 75% for IgM, and 100% specificity for both IgM and IgG (51,52) The positive ratios (onwards "Index": case or control sample MFI/pre-COVID sample MFI) were also considered for the analysis.…”