Fig. 3: Unique longitudinal profiles of mothers’ breast milk IgA response to SARS-CoV-2 show heterogeneity in antibody recognition.

a The line plots show breast milk IgA responses to SARS-CoV-2 and human common cold coronavirus selected full-length and protein fragments produced by the cell-free E. coli in vitro transcription and translation system. Antigens were selected to illustrate differences in reactivity profiles of four unique responders to SARS-CoV-2. The timing of breast milk sampling in days since onset of symptoms is shown on a free x-axis, and the normalized IgA signal intensity is shown in the y-axis. Each colored line represents an antigen’s IgA response measured for each of the longitudinal samples of one of the four mothers (each displayed in separate panels). aa amino acid, FL full-length, SCoV2 SARS-CoV-2, HCoV common cold human coronavirus. b The line plots show the log2 signal intensity of IgA responses to SARS-CoV-2 proteins assayed on the ECLIA platform (only SARS-CoV-2 proteins were assayed by ECLIA), where each panel is a unique mother’s responses to the four antigens. The number of days since onset of symptoms when samples were taken is shown on a free x-axis.