Extended Data Fig. 1: Specificity of subjects’ antibodies for SARS-CoV-2 S protein.
The specificity of antibodies for SARS-CoV-2 S protein compared to SARS-CoV-1 and MERS S protein was assayed in a cell-based IgG binding assay. HEK293T cells were transfected with S protein and its common variants from the indicated coronaviruses. The transfected cells were then incubated with human plasma from the indicated study groups and bound human IgG was detected using fluorescently tagged protein G (Methods). Shown are the percentage of the S protein transfected cells that are positive for human IgG in each patient group: CPD, black squares, n = 19; COVID-ARDS, red squares, n = 13; pediatric non-MIS-C, n = 28; MIS-C, green circles, n = 16; and control plasma from pre-pandemic donors (grey triangles; Neg, n = 6). Black bar indicates the median+interquartile range. P values were calculated by one-way ANOVA with Dunnett’s multiple comparisons test (CPD, SARS-CoV-2 vs. SARS-CoV-1: P = 0, SARS-CoV-2 vs. MERS: P = 0; COVID-ARDS, SARS-CoV-2 vs. SARS-CoV-1: P = 0, SARS-CoV-2 vs. MERS: P = 0; Ped non-MIS-C, SARS-CoV-2 vs. SARS-CoV-1: P = 0, SARS-CoV-2 vs. MERS: P = 0; MIS-C, SARS-CoV-2 vs. SARS-CoV-1: P = 0, SARS-CoV-2 vs. MERS: P = 0; Negative control, SARS-CoV-2 vs. SARS-CoV-1: P = 0.32, SARS-CoV-2 vs. MERS: P = 0.52).
