VERTICAL TRANSFER of the oral microbiome occurs from mother to child, with less dysbiosis by vaginal birth, no use of antibiotics, and breast feeding. This microbiome continues “a dialogue” with the host immune system via host pattern recognition receptors (PPRs) and Toll-like receptors (TLR) playing a key role.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4071637/