Comparison of Human Milk Immunoglobulin Survival during Gastric Digestion between Preterm and Term Infants.

Veronique Demers-Mathieu,Robert L Beverly,Mark A Underwood,David C Dallas,Søren D Nielsen

doi:10.3390/nu10050631

Veronique Demers-Mathieu, Robert L Beverly + Show 3 more

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https://doi.org/10.3390/nu10050631

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Abstract

Human milk provides immunoglobulins (Igs) that supplement the passive immune system of neonates; however, the extent of survival of these Igs during gastric digestion and whether this differs between preterm and term infants remains unknown. Human milk, and infant gastric samples at 2 h post-ingestion were collected from 15 preterm (23–32 week gestational age (GA)) mother-infant pairs and from 8 term (38–40 week of GA) mother-infant pairs within 7–98 days postnatal age. Samples were analyzed via ELISA for concentration of total IgA (secretory IgA (SIgA)/IgA), total secretory component (SC/SIgA/SIgM), total IgM (SIgM/IgM), and IgG as well as peptidomics. Total IgA concentration decreased by 60% from human milk to the preterm infant stomach and decreased by 48% in the term infant stomach. Total IgM and IgG concentrations decreased by 33% and 77%, respectively, from human milk to the term infant stomach but were stable in the preterm infant stomach. Release of peptides from all Ig isotypes in the term infant stomach was higher than in the preterm stomach. Overall, the stability of human milk Igs during gastric digestion is higher in preterm infant than in term infants, which could be beneficial for assisting the preterm infants’ immature immune system.

Highlights

Immunoglobulins (Igs) are important effectors of the adaptive immune system [1]
Total IgA concentration in preterm milk and gastric samples decreased with increased postnatal age, postmenstrual age (PMA), and body weight at sampling (BWs) (p < 0.05) but did not change in term samples (p > 0.05) (Table S3)
Total IgA concentration in human milk or gastric contents did not change across gestational age (GA) and feed volume within preterm and term infants (p > 0.05, Table S3)

Summary

Introduction

The mother’s placenta transports IgG to the fetus via a neonatal Fc receptor. These maternal IgG antibodies protect the infant during the first 6 months of postnatal age while the infant’s own immune system is developing [2]. Human milk provides another form of protection against pathogens for infants, as it contains an array of Igs, including IgA, secretory IgA (SIgA), IgM, secretory IgM (SIgM), and IgG [3,4]. Though human milk provides different Ig isotypes, milk SIgA is thought to be the most important in the infant gut as it neutralizes bacterial and viral pathogens by binding to them, reducing their ability to interact with epithelial cells and infect [6,7]. The presence of SIgA in human milk temporarily replaces the normal intestinal SIgA secretion that is lacking in the infant until 4 weeks of postnatal age [8]

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