Evaluation of a New Spike (S)-Protein-Based Commercial Immunoassay for the Detection of Anti-SARS-CoV-2 IgG

• Published in: Microorganisms (Basel) Vol. 9; no. 4; p. 733
• Main Authors: Eberhardt, Kirsten Alexandra, Dewald, Felix, Heger, Eva, Gieselmann, Lutz, Vanshylla, Kanika, Wirtz, Maike, Kleipass, Franziska, Johannis, Wibke, Schommers, Philipp, Gruell, Henning, Brensing, Karl August, Müller, Roman-Ulrich, Augustin, Max, Lehmann, Clara, Koch, Manuel, Klein, Florian, Di Cristanziano, Veronica
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 31.03.2021; MDPI
• Subjects: Antibodies; antibody formation; Antibody response; blood serum; Coronaviruses; COVID-19; COVID-19 infection; Enzyme-linked immunosorbent assay; humoral response; Immunoassay; Immunoglobulin G; Infections; Investigations; Neutralization; non-responder; nucleocapsid; Nucleocapsids; pandemic; Pandemics; protection; Proteins; Sensitivity analysis; Serology; Severe acute respiratory syndrome coronavirus 2; Spikes; titer; Viral diseases; Viral infections; viruses; United States > US; Germany; COVID-19; antibody; neutralization; titer; coronavirus; protection; sensitivity; pandemic; non-responder; humoral response
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms9040733

Background: The investigation of the antibody response to SARS-CoV-2 represents a key aspect in facing the COVID-19 pandemic. In the present study, we compared the new Immundiagnostik IDK® anti-SARS-CoV-2 S1 IgG assay with four widely-used commercial serological assays for the detection of antibodies targeting S (spike) and NC (nucleocapsid) proteins. Methods: Serum samples were taken from an unbiased group of convalescent patients and from a negative control group. Sample were simultaneously analyzed by the new Immundiagnostik IDK® anti-SARS-CoV-2 S1 IgG assay, by the DiaSorin LIAISON® SARS-CoV-2 S1/S2 IgG assay, and by the Euroimmun anti-SARS-CoV-2 S1 IgG ELISA. Antibodies binding NC were detected by the Abbott SARS-CoV-2 IgG assay and by the pan-immunoglobulin immunoassay Roche Elecsys® anti-SARS-CoV-2. Moreover, we investigated samples of a group of COVID-19 convalescent subjects that were primarily tested S1 IgG non-reactive. Samples were also tested by live virus and pseudovirus neutralization tests. Results: Overall, the IDK® anti-SARS-CoV-2 S1 IgG assay showed the highest sensitivity among the evaluated spike (S) protein-based assays. Additionally, the Immundiagnostik assay correlated well with serum-neutralizing activity. Conclusions: The novel IDK® anti-SARS-CoV-2 S1 IgG assay showed high sensitivity and specificity, representing a valid option for use in the routine diagnostic.