Fig. 2: SARS-CoV-2 specific antibody detection in COVID-19 and convalescent plasma samples.

a Measurement of spike protein and nucleocapsid protein-specific IgG and spike protein-specific IgM and IgA antibodies as described in Fig. 1. Area under the curve (AUC) values of plasma antibodies were calculated from reciprocal dilution curves in antibody detection assay (n = 256 for S-RBD IgG and Nucleocapsid IgG, n = 50 for S-RBD IgM, n = 144 for S-RBD IgA). Dotted lines indicate the negative threshold calculated by adding 1 standard deviation to the mean AUC values of healthy controls’ plasma. Horizontal bars show the mean value. Green, blue, salmon, red and yellow dots indicate negative controls, outpatient, hospitalized, ICU/deceased and plasma donor subjects, respectively. b S-RBD-specific IgG subclass AUC levels (n = 144 for S-RBD IgG1, n = 74 for S-RBD IgG2, S-RBD IgG3 and S-RBD IgG4) c S-RBD IgG AUC values of subject plasma grouped by outpatient, hospitalized, ICU or deceased and plasma donors (n = 115) d Nucleocapsid protein IgG AUC values of subject plasma grouped by outpatient, hospitalized, ICU or deceased and convalescent plasma donors (n = 115). e S-RBD IgA AUC values of subject plasma grouped by outpatient, hospitalized, ICU or deceased and plasma donors (n = 115). f S-RBD IgG AUC values of severity groups and plasma donors subdivided into males and females (n = 115). Green dots show female subjects while purple squares indicate male subjects. Statistical significances were determined using two-tailed Mann–Whitney U test.