Prenatal Priming of Cord Blood T Lymphocytes by Microbiota in the Maternal Vagina

In the vagina of women at the reproductive age, more than 170 strains of bacteria and yeasts are found. The effect of vaginal flora on neonatal T cells is yet to be investigated. We analyzed CD45RA and CD45RO expression on neonatal CD4+ T cells and cytokine production in CBMC cultures (interferon-gamma (IFN-gamma ), interleukin-4 (IL-4) and IL-12) related to vaginal bacteria isolated from a maternal vagina. We collected vaginal swabs from 36 women at the first stage of the delivery and cord blood from their newborns. IFN-gamma, IL-4, and IL-12 in stimulated CBMC were measured and the expression of CD45RA/CD45RO on CD4+ T cells was assessed. We noted the difference in CD45RO CD4+ expression and IL-12 levels between the newborns whose mothers were or were not colonized with Lactobacillus in the vagina (newborns whose mothers were colonized with Lactobacillus: CD45RO-10%+/- 3; IL-12-0.2 pg/mL +/- 0.05; newborns whose mothers were not colonized with Lactobacillus: CD45RO-6%+/- 3; IL-12-2.0 pg/mL +/- 0.7). Our results may indicate that lactobacilli in maternal vagina influence the development of neonatal immune system. Yet, more research is needed using specified bacterial antigens.