ORF8 and ORF3b antibodies are accurate serological markers of early and late SARS-CoV-2 infection
Asmaa Hachim, Niloufar Kavian, Carolyn A. Cohen, Alex W. H. Chin, Daniel K. W. Chu, Chris K. P. Mok, Owen T. Y. Tsang, Yiu Cheong Yeung, Ranawaka A. P. M. Perera, Leo L. M. Poon, J. S. Malik Peiris & Sophie A. Valkenburg
Nature Immunology (2020)
Abstract
The SARS-CoV-2 virus emerged in December 2019 and has caused a worldwide pandemic due to the lack of any pre-existing immunity. Accurate serology testing is urgently needed to help diagnose infection, determine past exposure of populations and assess the response to a future vaccine. The landscape of antibody responses to SARS-CoV-2 is unknown. In this study, we utilized the luciferase immunoprecipitation system to assess the antibody responses to 15 different SARS-CoV-2 antigens in patients with COVID-19. We identified new targets of the immune response to SARS-CoV-2 and show that nucleocapsid, open reading frame (ORF)8 and ORF3b elicit the strongest specific antibody responses. ORF8 and ORF3b antibodies, taken together as a cluster of points, identified 96.5% of COVID-19 samples at early and late time points of disease with 99.5% specificity. Our findings could be used to develop second-generation diagnostic tests to improve serological assays for COVID-19 and are important in understanding pathogenicity.
