Objective The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic challenges national health systems and the global economy. Monitoring of infection rates and seroprevalence can guide public health measures to combat the pandemic. This depends on reliable tests on active and former infections. Here, we set out to develop and validate a specific and sensitive enzyme linked immunosorbent assay (ELISA) for detection of anti-SARS-CoV-2 antibody levels. Methods In our ELISA, we used SARS-CoV-2 receptor-binding domain (RBD) and a stabilized version of the spike (S) ectodomain as antigens. We assessed sera from patients infected with seasonal coronaviruses, SARS-CoV-2 and controls. We determined and monitored IgM-, IgA- and IgG-antibody responses towards these antigens. In addition, for a panel of 22 sera, virus neutralization and ELISA parameters were measured and correlated. Results The RBD-based ELISA detected SARS-CoV-2-directed antibodies, did not cross-react with seasonal coronavirus antibodies and correlated with virus neutralization ( R 2 = 0.89). Seroconversion started at 5 days after symptom onset and led to robust antibody levels at 10 days after symptom onset. We demonstrate high specificity (99.3%; N = 1000) and sensitivity (92% for IgA, 96% for IgG and 98% for IgM; > 10 days after PCR-proven infection; N = 53) in serum. Conclusions With the described RBD-based ELISA protocol, we provide a reliable test for seroepidemiological surveys. Due to high specificity and strong correlation with virus neutralization, the RBD ELISA holds great potential to become a preferred tool to assess thresholds of protective immunity after infection and vaccination. Electronic supplementary material The online version of this article (10.1007/s15010-020-01503-7) contains supplementary material, which is available to authorized users.
【저자키워드】 COVID-19, SARS-CoV-2, S protein, serology, ELISA, Spike protein, Receptor binding domain, Virus neutralization, Antibody test, Assay validation, 【초록키워드】 antibodies, IgG, coronavirus, vaccination, pandemic, protocol, antibody, Seroprevalence, Infection, severe acute respiratory syndrome Coronavirus, ELISA, serum, sensitivity, specificity, infections, Seroconversion, anti-SARS-CoV-2 antibody, protective immunity, RBD, IgA, sera, response, Patient, Virus neutralization, antigens, monitoring, infection rate, seasonal coronaviruses, respiratory, correlation, threshold, public health measure, symptom onset, acute respiratory syndrome, supplementary material, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, infection rates, enzyme, domain, public health measures, ectodomain, thresholds, parameter, RBD ELISA, RBD-based ELISA, objective, controls, robust, national health system, Result, described, develop, addition, correlated, the RBD, were measured, cross-react, immunosorbent, R 2, 【제목키워드】 neutralization, Serological assay, SARS-CoV-2 antibody, COVID-19 patient, detect,