Complement in breast milk confers protection against enteric infection via shaping offspring gut microbiota

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Presentation Time: 02:15 PM - 03:30 PM
Poster Board Number: B104
Abstract ID: 4775

Presenting Author:
Dongqing Xu , Assistant Scientist at Johns Hopkins Bloomberg Sch. of Pub. Hlth.

Abstract:

Breastfeeding offers demonstrable benefits to newborns and infants by providing nourishment, immune protection, and shaping offspring gut commensal microbiota. Although it has been appreciated for decades that breast milk contains complement components, the physiological relevance of complement in breast milk remains undefined. Our recent work revealed that complement in breast milk shapes offspring gut microbiota, thus conferring protection against enteric bacterial infection. Specifically, weanling mice fostered by complement-deficient dams rapidly succumb when exposed to murine pathogen Citrobacter rodentium (CR), whereas pups receiving complement-sufficient breast milk are refractory to CR challenge. Mechanistically, complement in breast milk directly lyses selective gram-positive bacteria in infant gut commensal community via an antibody-independent pathway that leads to complement activation. The reshaped offspring gut microbiota, with altered abundance of gram-positive Staphylococcus, is correlated with the sensitivity of weanling mice to CR infection. Together, our findings reveal that complement in breast milk performs a critical function in shaping the offspring gut microbiota via eliminating selective microbe, thus protecting against environmental pathogens and promoting infant health.