摘要：SummaryThe SARS-CoV-2 immune response in human milk has not yet been examined, although protecting infants and young children from COVID-19 is critical for limiting community transmission and preventing serious illness and death. Here, milk samples from eight COVID-19-recovered and seven COVID-19-suspected donors were tested for antibody (Ab) binding to the SARS-CoV-2 Spike protein. All samples exhibited significant specific IgA reactivity to the full Spike, whereas 80% exhibited significant IgA and secretory (s)Ab binding to the Receptor-Binding Domain (RBD). Additionally, 67% samples exhibited IgG and/or IgM binding to RBD. IgA and sAb titers were highly correlated, indicating most IgA to be sIgA. Overall, these data indicate that a robust sIgA-dominant SARS-CoV-2 Ab response in human milk after infection should be expected in a significant majority of individuals. Further research is highly warranted to determine Ab functionality and the potential for exploiting extracted milk sIgA for therapeutic use.Graphical AbstractDisplay OmittedHighlights•All milk from recovered donors contained significant SARS-CoV-2-specific IgA•Most IgA could bind the Receptor-Binding Domain (important neutralization epitope)•Most Receptor-Binding Domain-specific IgA was in secretory (s) form•sIgA is durable in the mucosa, and thus potentially as a respiratory therapeuticPediatrics; Immunology; Virology
