Selective Transfer of Maternal Antibodies in Preterm and Term Children

Preterm newborns are more likely to suffer from infectious diseases at birth compared to children delivered at term. Whether this is due to compromised cellular, humoral, or organ-specific development remains unclear. Recent studies have shown that while preterm children have an aberrant cellular immune response, these infants receive similar maternal anti-viral IgG repertoires compared to term children, albeit at lower concentrations. These data point to selectivity in placental transfer at distinct gestational ages, to ensure that children are endowed with the most robust humoral immunity even if born preterm. To begin to define the mechanism by which preterm selective transfer may occur, the overall quantity and functional quality of an array of vaccine-, endemic pathogen-, and common antigen-specific antibodies were assessed across a cohort of 11 preterm and 12 term-delivered mother:infant pairs from birth through week 12. Although higher antibody levels were present in term infants, the overall functional profiles of antigen-specific antibodies were very similar. Temporal transfer differences were ascertained across distinct antibody subpopulations, with early transfer of functional antibodies capable of binding to FcRn and FcγR2-3 receptors followed by the transfer of distinct IgG subclasses. These results provide new insights on maternal:fetal immunity, highlighting novel immune axes that may be manipulated to enhance neonatal immune transfer of antibodies through gestation.