AN ELECTRON-MICROSCOPE STUDY OF THE INTERACTION BETWEEN TRICHOMONAS-VAGINALIS AND EPITHELIAL-CELLS OF THE HUMAN AMNION MEMBRANE

The mechanism of cytopathogenicity of Trichomonas vaginalis is not wel l established. Adhesion of T. vaginalis to human epithelial cells is c onsidered a prerequisite for parasitic infection and its pathogenic ef fect. To investigate cytopathological changes in the host caused by T. vaginalis infection, human amnion membrane was used as an in vitro mo del. T. vaginalis strain WAA38 from axenic culture was allowed to inte ract with the epithelial layer of the human amnion membrane for 6 and 9 h. Structural changes resulting from the interaction between parasit e and host cells were studied with transmission (TEM) and scanning (SE M) electron microscopy. Analysis of the electron microscope data showe d that T. vaginalis established contact with the host cells as early a s after 6 h of incubation; however, a close attachment of parasites to the epithelial cells occurred only after 9 h. Amoeboid T. vaginalis f ormed numerous cytoplasmic extensions and adhered to the epithelial ce lls mostly through the portions of their body opposite the undulating membrane. A dense network of microfilaments was seen at the site of co ntact between T. vaginalis and epithelial cells. Damaged and desquamat ed epithelial cells were seen with TEM and SEM only in the areas where parasites were in direct contact with target cells.