Adhesion of Trichomonas vaginalis to plastic surfaces: requirement for energy and serum constituents

The ability of Trichomonas vaginalis to adhere to plastic surfaces in the presence of various agents and under different growth conditions was examined in wells of microtitre plates containing unsupplemented TYI medium or the same, with various supplements. Following incubation, the wells were thoroughly washed and adhesion was determined by microscopic counting of the adherent organisms. There was no detectable adhesion in the absence of both serum and carbohydrate. Optimal adhesion (about 10–20% of the total number of parasites) was obtained throughout the growth curve in culture media supplemented with either serum or serum Cohn fractions IV–I (rich in α-globulin) or IV-4 (rich in α + β-globulin) and 25 mM glucose, maltose or fructose, but not in plates pre-coated with the Cohn fractions. Cohn fraction II + III (rich in β + γ-globulin) moderately enhanced adhesion while Cohn fractions II (rich in γ-globulin) or V (albumin), fibronectin, Tamm-Horsfall glycoproteins and polylysine were without effect. Non-metabolizable sugars (methyl derivatives of glucose, mannose or fucose) did not support growth, but, surprisingly, enhanced adhesion. At 4 °C, the trichomonads were not able to adhere and pre-adherent organisms detached from the plastic surface. Optimal adhesion was obtained at a pH range of 6·5–7·5 but was already detectable at pH 5·5. Cytochalasin E markedly suppressed adhesion. The data taken together suggest that the firm, serum-dependent adhesion of T. vaginalis to plastic surfaces is apparently not influenced by the rate of multiplication, requires energy and the binding by the organisms of certain serum proteins, which possibly enhances their hydrophobic interaction with the plastic substratum.