Nucleocapsid Specific Diagnostics for the Detection of Divergent SARS-CoV-2 Variants

• Published in: Frontiers in immunology Vol. 13; p. 926262
• Main Authors: Isaacs, Ariel, Amarilla, Alberto A., Aguado, Julio, Modhiran, Naphak, Albornoz, Eduardo A., Baradar, Alireza A., McMillan, Christopher L. D., Choo, Jovin J. Y., Idris, Adi, Supramaniam, Aroon, McMillan, Nigel A. J., Muller, David A., Young, Paul R., Woodruff, Trent M., Wolvetang, Ernst J., Chappell, Keith J., Watterson, Daniel
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 10.06.2022
• Subjects: Antibodies, Monoclonal; Antibodies, Neutralizing; COVID-19 - diagnosis; Humans; immunoassays; immunofluorescence; Immunology; immunoplaque assay; nanobody; nucleocapsid; Nucleocapsid - genetics; Nucleocapsid Proteins; Pandemics; SARS-CoV-2; SARS-CoV-2 - genetics; Single-Domain Antibodies; nucleocapsid; SARS-CoV-2; diagnostics; immunoassays; nanobody; immunoplaque assay; immunofluorescence
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2022.926262

Since the start of the COVID-19 pandemic, multiple waves of SARS-CoV-2 variants have emerged. Of particular concern is the omicron variant, which harbors 28 mutations in the spike glycoprotein receptor binding and N-terminal domains relative to the ancestral strain. The high mutability of SARS-CoV-2 therefore poses significant hurdles for development of universal assays that rely on spike-specific immune detection. To address this, more conserved viral antigens need to be targeted. In this work, we comprehensively demonstrate the use of nucleocapsid (N)-specific detection across several assays using previously described nanobodies C2 and E2. We show that these nanobodies are highly sensitive and can detect divergent SARS-CoV-2 ancestral, delta and omicron variants across several assays. By comparison, spike-specific antibodies S309 and CR3022 only disparately detect SARS-CoV-2 variant targets. As such, we conclude that N-specific detection could provide a standardized universal target for detection of current and emerging SARS-CoV-2 variants of concern.