The 89th Annual Meeting of the American Association of Physical Anthropologists (2020)

Reactive vs. proactive strategies for milk immunity


1Anthropology, Binghamton University (SUNY), 2Kilimanjaro Clinical Research Institute, Kilimanjaro Clinical Research Institute

April 17, 2020 4:45PM, Diamond 2 Add to calendar

Immune factors in human milk are numerous, and together constitute the immune system of milk. The immune system of milk represents a substantial maternal investment, which is important to infant survival. We have observed that stronger pro-inflammatory responses in milk (in vitro interleukin-6, IL-6, production during incubation with Salmonella) decrease infants’ risk for infectious disease (ID). We further predict that ID in a breastfeeding infant will lead mothers to bolster milk pro-inflammatory responses. We evaluated this hypothesis among mother-infant dyads in Kilimanjaro, Tanzania. Milk IL-6 responses to Salmonella were characterized at baseline and during infant ID among 55 mother-infant dyads. The median change in IL-6 response (sick - baseline) was 0 (range: -55, 162), and it was inversely associated with the strength of the baseline visit IL-6 response (B: -7.7; p: 0.001): those with the lowest initial IL-6 responses exhibited the most positive change in IL-6 response for children undergoing an ID. This may reflect a constraint on milk immunity: the higher the initial IL-6 response, the less it could be further increased. This may also reflect a divergence in strategies: a “proactive” strategy of high milk pro-inflammatory responses to decrease infants’ risk for ID vs. a “reactive” strategy of increasing milk pro-inflammatory responses for a sick infant. Additional independent predictors of the change in IL-6 response to Salmonella were maternal anemia (B: 13.22; p: 0.064) and prior pregnancy loss (B: 15.69; p: 0.034); these may be indicators of poor maternal condition, which could push mothers toward a “reactive” strategy.

Funding for this project was provided by the Wenner-Gren Foundation, the Leakey Foundation, The American Philosophical Society, and Binghamton University (SUNY)

Slides/Poster (pdf)