Pregnancy associates with alterations to the host and microbial proteome in vaginal mucosa

PROBLEM: Pregnant women are at increased risk of HIV acquisition, but the biological mechanisms contributing to this observation are not well understood. METHOD OF STUDY: Here, we assessed host immune and microbiome differences in the vaginal mucosa of healthy pregnant and non‐pregnant women using a metaproteomics approach. Cervicovaginal lavage (CVL) samples were collected from 23 pregnant and 25 non‐pregnant women. RESULTS: Mass spectrometry analysis of CVL identified 550 human proteins and 376 bacterial proteins from 11 genera. Host proteome analysis indicated 56 human proteins (10%) were differentially abundant (P < .05) between pregnant and non‐pregnant women, including proteins involved in angiogenesis (P = 3.36E‐3), cell movement of phagocytes (P = 1.34E‐6), and permeability of blood vessels (P = 1.27E‐4). The major bacterial genera identified were Lactobacillus, Gardnerella, Prevotella, Megasphaera, and Atopobium. Pregnant women had higher levels of Lactobacillus species (P = .017) compared with non‐pregnant women. Functional pathway analysis indicated that pregnancy associated with changes to bacterial metabolic pathway involved in energy metabolism, which were increased in pregnant women (P = .035). CONCLUSION: Overall, pregnant women showed differences in the cervicovaginal proteome and microbiome that may be important for HIV infection risk.