SARS-CoV-2 infection-induces human milk antibodies capable of mediating multiple functional activities

Authors: SHEEHAN, JARED - Louisiana State University; ANDRES, ALINE - Arkansas Children'S Nutrition Research Center (ACNC); Yeruva, Laxmi; RAMSAY, ALISTAIR - Louisiana State University

Submitted to: Clinical Nutrition Open Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/2024
Publication Date: 10/15/2024
Citation: Sheehan, J., Andres, A., Yeruva, V., Ramsay, A. 2024. SARS-CoV-2 infection-induces human milk antibodies capable of mediating multiple functional activities. Clinical Nutrition Open Science. https://doi.org/10.1016/j.nutos.2024.10.009.
DOI: https://doi.org/10.1016/j.nutos.2024.10.009

Interpretive Summary: Human milk provides a continuous source of antibodies to infant’s gut, which are protective against a variety of pathogens. Passive transfer of antibodies is a potential mode of protection for newborns and infants following maternal viral infections. It this study we characterized SARS-CoV-2 Spike (S)-specific antibodies in human milk samples collected longitudinally from COVID19 diagnosed mothers. Our findings indicated that human milk from virus infected mothers has the capacity to transfer viral-specific antibodies to neutralize the virus in newborns via breastfeeding.

Technical Abstract: Breastfeeding provides a continuous source of antibodies to infant’s gastrointestinal mucosa that are protective against a variety of pathogens. Passive transfer of antibodies is a potential mode of protection for newborns and infants following maternal SARS-CoV-2 infection. The primary goal of this study was to evaluate and characterize SARS-CoV-2 Spike (S)-specific antibodies in human milk samples collected longitudinally from a cohort of convalescent mothers. Robust S-reactive IgM, IgG and IgA ELISA titers were found at day 7 after enrollment , with IgG and IgA levels persisting through 6 months. The majority of S-reactive IgA in milk was secretory in nature. S-reactive IgG and IgA antibodies were also found in paired mother-infant sera, with no significant differences in titers between mothers and infants. This was also the case for S pseudovirus neutralizing antibody (nAb) activity in these sera, correlating most strongly with S-specific serum IgG. Human milk purified IgG and IgA showed limited nAb activity against S-pseudovirus and was present in three of twelve subjects at 3 days after the onset of symptoms. In contrast, strong IgG (mean IC50 value 29.19'g/ml) and IgA (mean IC50 value 10.17'g/ml) nAb activity was found in all samples at 14 days with a decline by 3 months after the onset of symptoms, which was not present in pre-pandemic controls. Purified human milk IgG and IgA antibodies showed limited phagocytic activity at day 3 but increased significantly in all subjects by day 14 after the onset of symptoms. Taken together, our findings indicate that human milk from SARS-CoV-2 infected mothers has the capacity to transfer SARS-CoV-2-specific antibodies with multiple functional activities to newborns via breastfeeding.