Alderete J F, Garza G E
Infect Immun. 1985 Dec;50(3):701-8. doi: 10.1128/iai.50.3.701-708.1985.
The adherence of Trichomonas vaginalis NYH 286 to host cells was evaluated by using monolayer cultures of HeLa and HEp-2 epithelial cells and human fibroblast cell lines. Saturation of sites on HeLa cells was achieved, yielding a maximal T. vaginalis NYH 286-to-cell ratio of two. The ability of radiolabeled NYH 286 to compete with unlabeled trichomonads for attachment and the time, temperature, and pH-dependent nature of host cell parasitism reinforced the idea of specific parasite-cell associations. Other trichomonal isolates (JH31A, RU375, and JHHR) were also found to adhere to cell monolayers, albeit to different degrees, and all isolates produced maximal contact-dependent HeLa cell cytotoxicity. The avirulent trichomonad, Trichomonas tenax, did not adhere to cell monolayers and did not cause host cell damage. Interestingly, parasite cytadherence was greater with HeLa and HEp-2 epithelial cells than with fibroblast cells. In addition, cytotoxicity with fibroblast cells never exceeded 20% of the level of cell killing observed for epithelial cells. Elucidation of properties of the pathogenic human trichomonads that allowed for host cell surface parasitism was also attempted. Treatment of motile T. vaginalis NYH 286 with trypsin diminished cell parasitism. Incubation of trypsinized organisms in growth medium allowed for regeneration of trichomonal adherence, and cycloheximide inhibited the regeneration of attachment. Organisms poisoned with metronidazole or iodoacetate failed to attach to host cells, and adherent trichomonads exposed to metronidazole or iodoacetate were readily released from parasitized cells. Coincubation experiments with polycationic proteins and sugars and pretreatment of parasites or cells with neuraminidase or periodate had no effect on host cell parasitism. Colchicine and cytochalasin B, however, did produce some inhibition of adherence to HeLa cells. The data suggest that metabolizing T. vaginalis adheres to host cells via parasite surface proteins in a specific receptor-ligand fashion. Furthermore, parasitism of epithelial cells appears to render this cell type more susceptible than fibroblast cell types to contact-dependent cytotoxicity.
利用HeLa细胞、HEp - 2上皮细胞和人成纤维细胞系的单层培养物，评估阴道毛滴虫NYH 286对宿主细胞的黏附情况。HeLa细胞上的位点达到饱和，阴道毛滴虫NYH 286与细胞的最大比例为2。放射性标记的NYH 286与未标记的滴虫竞争附着的能力，以及宿主细胞寄生的时间、温度和pH依赖性特性，强化了特定寄生虫 - 细胞关联的观点。还发现其他滴虫分离株（JH31A、RU375和JHHR）也能黏附于细胞单层，尽管程度不同，且所有分离株均产生最大程度的接触依赖性HeLa细胞细胞毒性。无毒的口腔毛滴虫不黏附于细胞单层，也不引起宿主细胞损伤。有趣的是，阴道毛滴虫对HeLa细胞和HEp - 2上皮细胞的细胞黏附性比对成纤维细胞的黏附性更强。此外，成纤维细胞的细胞毒性从未超过上皮细胞观察到的细胞杀伤水平的20%。还尝试阐明致病性人毛滴虫允许宿主细胞表面寄生的特性。用胰蛋白酶处理活动的阴道毛滴虫NYH 28能减少细胞寄生。将经胰蛋白酶处理的生物体在生长培养基中孵育可使滴虫黏附再生，而环己酰亚胺可抑制黏附的再生。用甲硝唑或碘乙酸中毒的生物体无法黏附于宿主细胞，暴露于甲硝唑或碘乙酸的黏附滴虫很容易从寄生细胞中释放出来。与聚阳离子蛋白和糖的共孵育实验以及用神经氨酸酶或高碘酸盐对寄生虫或细胞进行预处理对宿主细胞寄生没有影响。然而，秋水仙碱和细胞松弛素B确实对黏附于HeLa细胞有一定抑制作用。数据表明，代谢活跃的阴道毛滴虫通过寄生虫表面蛋白以特定的受体 - 配体方式黏附于宿主细胞。此外，上皮细胞的寄生似乎使这种细胞类型比成纤维细胞类型更容易受到接触依赖性细胞毒性的影响。
