Heritable Vaginal Bacteria Relate to Allergic Sensitization

Perturbed infant gut microbiota associates with risk of childhood allergic diseases. Maternal asthma status and exposures during pregnancy further increase childhood asthma risk, which suggests these observations are linked by inter-generational microbial transmission. Using maternal vaginal (n=184) and paired infant stool (n=172) samples, we identified four compositionally and functionally distinct Lactobacillus-dominated vaginal microbiota clusters (VCs), differentially related with maternal exposures and infant allergic sensitization. Variance in inherited vaginal bacteria correlated with VC, maternal allergy and asthma status and with infant serum IgE. Inherited IgE-discriminatory bacterial pathways were identified and fatty acid synthesis, histamine and tryptophan degradation bacterial pathways were associated with lower IgE. Two strains of vertically-transmitted Lactobacillus were isolated from fetal meconium and induced immunosuppressive phenotypes on human antigen presenting cells in vitro. In vivo, supplementation with Lactobacillus jensenii reduced lung eosinophils, neutrophilic expansion and the proportion of IL4+ CD4+ T cells. Thus, bacterial and asthma heritability are intimately linked, and implicate a microbial basis of inter-generational disease transmission.