Fig. 3: SARS-CoV-2 IgM, IgG and IgA epitope repertoires in children.

IgM, IgG and IgA antibody epitope repertoire recognized in the SARS-CoV-2-infected sera from children with mild/moderate (M) or severe (S) COVID-19 or MIS-C across the whole proteome of SARS-CoV-2 encoding four structural proteins (S, E, M and N) as well as 16 NSPs and 9 accessory proteins. The schematic on top shows various proteins in the full proteome of SARS-CoV-2. The ORF1ab polypeptide encoding various NSPs (numbered sequentially based on occurrence) is shown. Other proteins are labeled as spike (S), ORF3a (3a), ORF4 (E), ORF5 (M), ORF7a (7a), ORF8 (8), ORF9a (N), ORF9b (9b), ORF9c (9c) and ORF10 (10). Epitope coverage map shows alignment position (amino acid position) on the x axis and coverage (phage clone frequency) of each position on the y axis defined by epitopes recognized by IgG, IgM and IgA in mild/moderate and severe COVID-19 (orange and red, respectively) and in mild/moderate and severe MIS-C (cyan and blue, respectively). The y axis shows phage clone frequency in the range of 0–200 for IgM, IgG or IgA selections with these samples, 0–1,000 for IgM clones with severe COVID-19 and 0–500 for severe MIS-C. Owing to higher frequency of selected phage clones, the original clone frequencies (y axis) of spike and ORF3a antigenic sites were scaled (a scaling ratio of 5.25 was applied for spike sites 7,738–7,799 and 3.05 for ORF3a sites 8,407–8,438) to aid in data visualization. Samples were fresh and not frozen and thawed. All samples were run in one batch at the same time for each assay. The GFPDL affinity selection was performed in duplicate (two independent experiments were performed by a researcher in the laboratory, who was blinded to sample identity). Similar numbers of bound phage clones and epitope repertoire were observed in the GFPDL panning.

Source data