Evaluation of potential immunity against the novel severe acute respiratory syndrome (SARS) coronavirus that emerged in 2019 (SARS-CoV-2) is essential for health, as well as social and economic recovery. Generation of antibody response to SARS-CoV-2 (seroconversion) may inform on acquired immunity from prior exposure, and antibodies against the SARS-CoV-2 spike protein receptor binding domain (S-RBD) are speculated to neutralize virus infection. Some serology assays rely solely on SARS-CoV-2 nucleocapsid protein (N-protein) as the antibody detection antigen; however, whether such immune responses correlate with S-RBD response and COVID-19 immunity remains unknown. Here, we generated a quantitative serological ELISA using recombinant S-RBD and N-protein for the detection of circulating antibodies in 138 serial serum samples from 30 reverse transcription PCR–confirmed, SARS-CoV-2–hospitalized patients, as well as 464 healthy and non–COVID-19 serum samples that were collected between June 2017 and June 2020. Quantitative detection of IgG antibodies against the 2 different viral proteins showed a moderate correlation. Antibodies against N-protein were detected at a rate of 3.6% in healthy and non–COVID-19 sera collected during the pandemic in 2020, whereas 1.9% of these sera were positive for S-RBD. Approximately 86% of individuals positive for S-RBD–binding antibodies exhibited neutralizing capacity, but only 74% of N-protein–positive individuals exhibited neutralizing capacity. Collectively, our studies show that detection of N-protein–binding antibodies does not always correlate with presence of S-RBD–neutralizing antibodies and caution against the extensive use of N-protein–based serology testing for determination of potential COVID-19 immunity. Detection of SARS-CoV-2 nucleocapsid protein binding antibodies does not always correlate with the presence of spike protein receptor binding domain neutralizing antibodies.
【저자키워드】 COVID-19, immunology, Adaptive immunity, 【초록키워드】 SARS-CoV-2, coronavirus, immune response, pandemic, Immunity, Neutralizing antibodies, antibody, Antibody Response, detection, ELISA, Spike protein, Receptor binding domain, Protein, Health, Seroconversion, IgG antibody, Antibody detection, serology testing, sera, S-RBD, reverse transcription, neutralizing capacity, virus infection, correlation, serological, Quantitative, moderate, patients, binding antibody, COVID-19 immunity, acute respiratory syndrome, Viral protein, circulating antibody, individual, positive, SARS-CoV-2 nucleocapsid, N-protein, serum sample, Generation, neutralize, collected, healthy, exhibited, serology assay, the SARS-CoV-2, 【제목키워드】 antibody, Receptor binding domain, nucleocapsid, SARS-CoV-2 spike, COVID-19 immunity, implication,