Isolation of a cell-detaching factor of Trichomonas vaginalis

The pathogenetic role of soluble products of Trichomonas vaginalis growth in culture is controversial. To evaluate this role, T. vaginalis was grown in broth and cell culture and the cell-free filtrate was applied to fresh cell culture monolayers. When adjusted to pH 6.5, filtrates obtained from 22-h culture growth totally disrupted McCoy, HEp-2, human foreskin fibroblast, and Chinese hamster ovary cell monolayers within 6 h. These detached cells remained greater than 90% viable. This cell-detaching factor (CDF) was heat and acid labile, with a pH optimum of 6.5. CDF has trypsinlike activity which disrupts monolayer cells, but cells do not die if the pH is controlled. CDF was purified by ethanol precipitation, ammonium sulfate fractionation, and ion-exchange and gel filtration column chromatography. A 200,000-molecular-weight glycoprotein which was also immunogenic by immunoblot with human sera reactive to T. vaginalis was isolated in this manner. This confirms the presence of a specific soluble CDF derived from T. vaginalis whose application may be important as a diagnostic tool and in further studies of pathogenesis.