Non-pregnant CVF protome and peptidome

Cervical-vaginal fluid (CVF) covers the lower part of the female reproductive system and functions in the homeostasis and immunity of the surrounding tissues. The proteome of this proximal fluid has mainly been studied in pregnant women, whereas the CVF proteome of non-pregnant women has not been analyzed in great detail. The CVF peptidome has not been reported to date. In the current study, we separated pooled CVF samples from healthy non-pregnant women into proteomic and peptidomic fractions, followed by mass spectrometry analysis. In total, we identified 1,087 unique proteins in CVF, of which 801 proteins were not previously identified. The presence of the tissue specific proteins oviductal glycoprotein-1 (OVGP-1) and tubulin polymerization-promoting protein family member 3 (TPPP3) in CVF strongly suggests that the tissues of the upper female reproductive tract contribute to the protein composition of CVF. The tremendous catalytic potential of CVF was highlighted by the identification of 85 proteases. The majority of identified proteases belong to the serine protease catalytic type. Over 1,000 endogenous peptides were detected in the CVF peptidome, and 39 peptides are predicted to have antimicrobial activity. The detailed proteomic and peptidomic analysis of CVF will further aid in the delineation of physiological and pathobiological pathways related to reproduction, immunity and host defense, and assist in developing new biomarkers for malignant and other diseases of the female reproductive tract.