Impact of pertussis-specific IgA, IgM, and IgG antibodies in mother's own breast milk and donor breast milk during preterm infant digestion

Abstract

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 from infants fed DBM at 8-9 days. All pertussis antibodies were detected in infant stools at both postpartum times.

Conclusions: 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.

Impact: Pertussis-specific antibodies from mother's breast milk were stable during infant digestion, whereas anti-pertussis IgA and IgG from donor breast milk decreased in gastric contents. The constant region and variable region of pertussis-specific antibodies and the maternal immunization (previous infections and vaccinations) appear to be the critical factors for their stability to proteolytic digestion and pasteurization. Pertussis-specific antibodies from either mother's breast milk or donor breast milk survived during preterm infant digestion and both types of milk will compensate for the lower IgG transplacental transfer in preterm infants compared with term infants.

Fig. 1

Schema of the study design to determine the difference of pertussis-specific antibodies in mother’s own breast milk (MBM) and donor breast milk (DBM) in gastric contents and stool samples from preterm infants.

Fig. 2

Milk IgA specific to Bordetella pertussis filamentous hemagglutinin (anti-FHA) and pertussis toxin (anti-PT) in mother’s own breast milk (MBM) and donor breast milk (DBM) and gastric samples from preterm infants fed MBM and DBM (26–36 weeks of gestational age (GA)). a–d Relative abundance of anti-FHA IgA at 8–9 days postpartum, anti-PT IgA at 8–9 days postpartum, anti-FHA IgA at 21–22 days postpartum and anti-PT IgA at 21–22 days postpartum. Values are means ± SD, n = 20 for 8–9 days and n = 16 for 21–22 days postpartum. Asterisks show statistically significant differences between variables (***p < 0.001; **p < 0.01; *p < 0.05) using the Wilcoxon matched-pairs signed-rank test. EU, ELISA Units/mL.

Fig. 3

Milk IgM specific to Bordetella pertussis filamentous hemagglutinin (anti-FHA) and pertussis toxin (anti-PT) in mother’s own breast milk (MBM) and donor breast milk (DBM) and gastric samples from preterm infants fed MBM and DBM (26–36 weeks of gestational age (GA)). a–d Relative abundance of anti-FHA IgM at 8–9 days postpartum age, anti-PT IgM at 8–9 days postpartum, anti-FHA IgM at 21–22 days postpartum and anti-PT IgM at 21–22 days postpartum. Values are means ± SD, n = 20 for 8–9 days and n = 16 for 21–22 days postpartum. Asterisks show statistically significant differences between variables (***p < 0.001; **p < 0.01; *p < 0.05) using the Wilcoxon matched-pairs signed-rank test. EU, ELISA Units/mL.

Fig. 4

Milk IgG specific to Bordetella pertussis filamentous hemagglutinin (anti-FHA) and pertussis toxin (anti-PT) in mother’s own breast milk (MBM) and donor breast milk (DBM) and gastric samples from preterm infants fed MBM and DBM (26–36 weeks of gestational age (GA)). a–d Relative abundance of anti-FHA IgM at 8–9 days postpartum, anti-PT IgM at 8–9 days postpartum, anti-FHA IgM at 21–22 days postpartum and anti-PT IgM at 21–22 days postpartum. Values are means ± SD, n = 20 for 8–9 days and n = 16 for 21–22 days postpartum. Asterisks show statistically significant differences between variables (***p < 0.001; **p < 0.01; *p < 0.05) using the Wilcoxon matched-pairs signed-rank test. EU, ELISA Units/mL.

Fig. 5

Comparison of anti-pertussis reactivity antibodies (EU/mL) between raw human milk (RHM) and pasteurized whole human milk (PWHM) or pasteurized skimmed human milk (PSHM). a–f Reactivity of anti-formaldehyde-treated filamentous hemagglutinin (anti-FHA) IgA, IgM, IgG and of anti-pertussis toxin (anti-PT) IgA, IgM, IgG in RHM, PWHM or PSHM. Milk samples are from one mother who delivered one term infants with 38 wks of gestational age and 12 days postpartum. Values are means ± SD (n = 3). Asterisks show statistically significant differences between variables (*** p < 0.001;** p < 0.01;* p < 0.05).