Kathyayini P. Gopalakrishna

Abstract Group B Streptococcus (GBS; Streptococcus agalactiae) is an important pathobiont capable of colonizing various host environments, contributing to severe perinatal infections. Surface proteins play critical roles in GBS-host interactions, yet comprehensive studies of these proteins' functions have been limited by genetic manipulation challenges.

Immunoglobulin A (IgA) is secreted into breast milk and is critical for both protecting against enteric pathogens and shaping the infant intestinal microbiota. The efficacy of breast milk–derived maternal IgA (BrmIgA) is dependent upon its specificity; however, heterogeneity in BrmIgA binding ability to the infant microbiota is not known.

1. Introduction Mammals feed their infants milk for the period before they are capable of acquiring food on their own. Milk is also a mechanism by which a mother can protect the mucosal surfaces of their immunologically inexperienced infants from infection. In addition, maternal milk shapes the acquisition and development of the bacteria, archaea, viruses, protists, and fungi, collectively termed the microbiome, that colonize our barrier surfaces.