Impact of Pertussis-Specific IgA, IgM and IgG Antibodies in Mother’s Own Breast Milk and Donor Breast Milk during Preterm Infant Digestion

BACKGROUND: The survival of antibody isotypes specific to pertussis toxin (PT) and filamentous hemagglutinin (FHA) from mother’s own milk (MBM) and donor breast milk (DBM) during preterm infant digestion was investigated. METHODS: Feed, gastric and stool samples were collected from 20 preterm mother-infant pairs at 8–9 days and 21–22 days postpartum. Samples were analyzed via ELISA for anti-FHA or anti-PT immunoglobulin A (IgA), IgM and IgG. RESULTS: Anti-PT IgA, anti-FHA IgG and anti-PT IgG were lower in MBM than DBM at 8–9 days postpartum, whereas anti-FHA IgM was higher in MBM than DBM. Anti-PT IgA, anti-PT IgG and anti-FHA IgG in DBM decreased in gastric contents at both postpartum times but those antibodies in MBM were stable or increased during gastric digestion. Anti-FHA specific IgA and IgM were higher in gastric contents from infants fed MBM than that fed DBM at 8–9 days. All pertussis antibodies were detected in infant stools at both postpartum times. CONCLUSION: Pertussis-specific antibodies from MBM were stable during infant digestion, whereas anti-pertussis IgA and IgG from DBM decreased in gastric contents. The constant region and variable region of antibodies and maternal immunization appear to be the critical factors for their stability to proteolytic digestion and pasteurization.