Abstract
Large-scale serosurveillance of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) will only be possible if serological tests are sufficiently reliable, rapid and affordable. Many assays are either labour-intensive and require specialised facilities (e.g. virus neutralization assays), or are expensive with suboptimal specificity (e.g. commercial ELISAs and RDTs). Bead-based assays offer a cost-effective alternative and allow for multiplexing to test for antibodies against multiple antigens and against other pathogens. Here, we compare the performance of spike (S) and nucleocapsid (NP) antigens for the detection of SARS-CoV-2 specific IgG, IgM and IgA antibodies in a panel of sera that includes recent (up to six weeks after symptom onset, severe n = 44; and mild cases n = 52) and old infections (five months after symptom onset, mild n = 104), using a Luminex-bead based assay and comparison to a virus neutralization test. While we show that neutralizing antibody levels are significantly lower in mild than in severe cases, we demonstrate that a combination of the recombinant nucleocapsid protein (NP) and receptor-binding domain (RBD) results in highly specific (99 %) IgG antibody detection five months after infection in 96 % of cases. Although most severe Covid-19 cases developed a clear IgM and IgA response, titers fell below the detection threshold in more than 20 % of mild cases in our bead-based assay. In conclusion, our data supports the use of RBD and NP for the development of SARS-CoV-2 serological IgG bead-based assays.
Keywords: Bead-based assay; Luminex antibody test; Sars-CoV-2; Serosurveillance; Virus neutralization test.
【저자키워드】 SARS-CoV-2, Serosurveillance, virus neutralization test, Bead-based assay, Luminex antibody test, 【초록키워드】 neutralizing antibody, serological test, IgG, IgM, coronavirus, antibody, neutralization, Multiplexing, Infection, ELISA, nucleocapsid protein, Antigen, specificity, Recombinant nucleocapsid protein, IgG antibody, Receptor-binding domain, Serological tests, nucleocapsid, RBD, sera, virus neutralization test, neutralization test, severe cases, Mild, Pathogens, Antibody test, respiratory, threshold, serological, Combination, RDTs, titers, Support, symptom onset, acute respiratory syndrome, acute respiratory syndrome coronavirus, IgA antibodies, domain, mild cases, while, offer, significantly lower, IgA response, multiple antigens, virus neutralization assays, FIVE, include, assays, IgA antibody, mild case, multiple antigen, 【제목키워드】 nucleocapsid protein, Antibody detection, Mild, target, SARS-CoV-2 spike, COVID-19 case, Evaluating,