Human milk sIgA antibody in relation to maternal nutrition and infant vulnerability in northern Kenya

Abstract

Background The maternal buffering hypothesis posits that human lactation biology can buffer milk against the mild-to-moderate malnutrition that occurred routinely in evolutionary history through the mobilization of maternal body reserves. This perspective may provide insights for understanding human milk immune content variation, such as milk sIgA, which protects infants’ intestines from microbial colonization and prevents diarrheal disease. Objective To investigate how maternal delivery of sIgA to milk may vary in a way that can buffer milk against maternal malnutrition, while taking into consideration infants’ varying needs for immune protection across age or by sex. Methodology A cross-sectional study analyzed archived milk specimens from breastfeeding mothers in Ariaal communities of northern Kenya surveyed during the 2006 Horn-of-Africa drought. Multiple regression models for ln-transformed sIgA were constructed using maternal nutrition, infant age/sex and their interactions as predictors. Maternal nutrition variables included iron-deficiency anemia (IDA), vitamin A deficiency (VAD) and mid-upper arm circumference (MUAC). Infant vulnerability was considered high in young age and/or male sex. Results and implications Milk sIgA did not significantly differ by maternal IDA. Milk sIgA increased with infant age and maternal MUAC (n = 202). Significant interactions were observed between infant age and maternal VAD and between infant sex and maternal MUAC, such that milk sIgA content was low for younger infants particularly among VAD mothers, while among mothers with low MUAC, sIgA was lower for male infants. Results imply that mothers’ ability to deliver/buffer milk sIgA may be lowered when nutritional stress is combined with high infant vulnerability to infection. Lay Summary Human milk sIgA antibody content was low for younger infants among vitamin A deficient mothers. Among mothers with small arm-circumference, milk sIgA was lower for sons. Double burden of raising young or male infants with high needs for immune protection and being malnourished, might lower maternal sIgA delivery to milk.

Impact of maternal antibodies and microbiota development on the immunogenicity of oral rotavirus vaccine in African, Indian, and European infants

“…The high maternal RV-IgA levels in the UK may reflect the immunogenic nature of early rotavirus exposures and the subsequent boosting of antibodies by mild or asymptomatic re-infection 22 . Nutritional stress has also been linked with lower secretory IgA levels in breastmilk 23 , 24 . Consistent with this, we observed maternal breastmilk/serum RV-IgA ratios to be lowest in India and highest in the UK, with intermediate levels in Malawi.…”

Cell-Mediated Immune Ontogeny Is Affected by Sex but Not Environmental Context in a Long-Lived Primate Species

“…Apart from maternal effects caused by caregiving behavior (Bercovitch, 2002;Koskela et al, 2004), maternal milk composition may vary in relation to offspring sex (Hinde, 2009;Galante et al, 2018). Of particular relevance to immune ontogeny is the finding that human mothers provide less secretory immunoglobulin to sons than to daughters with their milk (Fujita et al, 2019). Intriguingly, the sex-specific differences in neopterin levels found in our study diminish around weaning age in apes (de Lathouwers and Van Elsacker, 2006;Fahy et al, 2014;Bãdescu et al, 2016).…”

In Vitro Stimulation of Whole Milk Specimens: A Field-Friendly Method to Assess Milk Immune Activity

“…Some of the patterns we observed in cytokine responses are counter-intuitive. Child age was positively associated with IL-6 responses to many stimuli (Negative, Escherichia, Lactobacillus, and Ascaris), indicating stronger proinflammatory responses for older children; this contrasts with the expectation that milk immune protection should be enhanced for vulnerable children (Breakey et al, 2015;Fujita et al, 2019), such as young infants, whose immature immune systems leave them particularly vulnerable to infectious diseases (Simon et al, 2015).…”

“…Cytokine concentrations of IL-4, IL-6, IL-10,and IFN-γ were estimated in all baseline and stimulated aqueous specimens using the Quansys Biosciences 4-plex High Sensitivity Human Cytokine (112549HU) kit. Baseline milk specimens were further characterized with estimation of two established biomarkers: secretory immunoglobulin A (sIgA), which is frequently interpreted to reflect the protective immune capacity of milk, and interleukin-1 receptor antagonist (IL-1ra), which is interpreted to reflect the anti-inflammatory capacity of milk (Breakey et al, 2015; Fujita et al, 2019; Hassiotou et al, 2013; Miller, 2018). Concentrations of sIgA were estimated in baseline aqueous specimens with an in-house assay following Hassiotou and colleagues (2013).…”