Trichomonas vaginalis haemolysis: Evidence of functional pores formation on red cell membranes

Fiori, Pier Luigi

doi:10.1016/0378-1097(93)90435-5

Cited by 25 publications

(46 citation statements)

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“…Moreover, trichomoniasis is associated with an enhanced risk of neoplastic transformation in cervical tissues (38) and increased human immunodeficiency virus seroconversion in women (22,31). The mechanisms by which T. vaginalis exerts its pathogenic effects involve adhesion to host cells (1,2,19) and the activity of pH-dependent pore-forming proteins (14,15) and of cytoskeleton-disrupting proteases (16). M. hominis can be isolated from the genital tracts of both symptomatic and asymptomatic individuals.…”

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Long-Term Survival and Intracellular Replication of Mycoplasma hominis in Trichomonas vaginalis Cells: Potential Role of the Protozoon in Transmitting Bacterial Infection

et al. 2005

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The existence of a symbiotic relationship between Trichomonas vaginalis and Mycoplasma hominis, which is the first reported example of symbiosis between two obligate human pathogens, has been recently reported by our research group. In this work, we examined the cellular location of M. hominis in respect to T. vaginalis. By using gentamicin protection assays, double immunofluorescence, and confocal microscopy, we obtained strong evidence that M. hominis is located within protozoan cells. 5-Bromodeoxyuridine incorporation assays showed that intracellularly located mycoplasmas actively synthesize DNA. Our results demonstrate that M. hominis has the capability of entering trichomonad cells and of replicating inside the protozoon. These findings suggest that symbiosis might provide the bacteria, during human infection, with the capability to resist to environmental stresses, such as host defense mechanisms and pharmacological therapies.Trichomonas vaginalis is a parasitic protozoon responsible for trichomoniasis, one of the most common sexually transmitted diseases in humans, estimated to affect at least 200 million people worldwide (37). Studies carried out with large groups of women suffering from vaginitis showed that T. vaginalis is clinically associated with Mycoplasma hominis (18, 35), a bacterium that, like the protozoon, resides exclusively in the human genital tract. The association is strictly species specific, since is not observed with Ureaplasma urealyticum, another Mollicutes species that is a much more common inhabitant of the human genital tract. The clinical association between the two pathogens has been recently explained by the demonstration of a symbiotic relationship between T. vaginalis and M. hominis (27). More than 90% of T. vaginalis clinical isolates from our collection proved to be infected by M. hominis independent of their geographic origin. Our recent work has allowed us to shed light on some aspects of the phenomenon (28).The presence of endosymbionts in free-living protozoa is frequently described, but it has been never reported in obligate parasitic protozoa. The first example of symbiosis involving a human pathogen was described for Legionella pneumophila, a bacterial pathogen that is responsible for Legionnaire's disease, and Acanthamoeba sp., a free-living opportunistic amoeba (30). The relationship between T. vaginalis and M. hominis is the only one described so far involving two obligate human pathogens. T. vaginalis is responsible for severe vaginitis accompanied by abdominal pain, itching, and foul-smelling discharge (29) and is mainly asymptomatic in men (20). Moreover, trichomoniasis is associated with an enhanced risk of neoplastic transformation in cervical tissues (38) and increased human immunodeficiency virus seroconversion in women (22,31). The mechanisms by which T. vaginalis exerts its pathogenic effects involve adhesion to host cells (1, 2, 19) and the activity of pH-dependent pore-forming proteins (14, 15) and of cytoskeleton-disrupting proteases (16). M. hominis c...

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Long-Term Survival and Intracellular Replication of Mycoplasma hominis in Trichomonas vaginalis Cells: Potential Role of the Protozoon in Transmitting Bacterial Infection

et al. 2005

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“…Moreover, experiments were also performed after trypsinization of erythrocytes for digestion of the external protein domains (17). Erythrocytes were washed and prepared as described previously (18).…”

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Host and Tissue Specificity of Trichomonas vaginalis Is Not Mediated by Its Known Adhesion Proteins

2000

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Adhesion of Trichomonas vaginalis is believed to be dependent on four adhesion proteins, which are thought to bind to vaginal epithelial cells in a specific manner with a ligand-receptor type of interaction. However, the specific receptors on the host cell have not yet been identified. In this work, the ability of the T. vaginalis adhesins to bind to cells of different histologic derivations and from different species has been studied. HeLa, CHO, and Vero cell lines; erythrocytes from different species; and a prokaryote without a cell wall, Mycoplasma hominis, were employed in order to investigate the cell specificity of the T. vaginalis adhesins. We observed that the T. vaginalis adhesins are able to bind to the different cell types to the same extent, suggesting that the host and tissue specificity of T. vaginalis adhesion should not be due to specificity of the parasite adhesins. Our results suggest that the data published to date on the subject are probably artifactual and that the experiments reported in the literature are not appropriate for identification of protozoan adhesins.Trichomonas vaginalis is a flagellated protozoan parasite responsible for one of the most diffused sexually transmitted diseases. The microorganism parasitizes the urogenital tract in humans, with high tissue and host specificity (19). Adhesion of the protozoan to the host cell is the primary step leading to cytopathogenicity, which is contact dependent (16). In the past, several reports have described the molecular characterization of the different steps involved in interaction of the parasite with the human vaginal epithelial cells. Adhesion of the parasite is thought to be mediated by four trichomonad surface proteins, reportedly AP65, AP51, AP33, and AP23 (5, 6), which are believed to recognize specific proteins of the host by a ligand-receptor type of interaction (3,7,8), although the receptors in the host cell have not yet been identified. The putative role of these proteins in adhesion has been characterized by using HeLa cells, because of their epithelial nature and the genital epithelium origin. Moreover, these cells appear more susceptible to in vitro destruction by live T. vaginalis than other cell types (4). Although Arroyo et al. (7,8) were able to partially inhibit the binding of T. vaginalis to epithelial cells and to detect the adhesins on the protozoan surface by using polyclonal antibodies, Brugerolle et al. (10) recently demonstrated by immunogold staining with monoclonal antibodies that the putative adhesins are not localized on the trichomonad surface, but are restricted to a hydrogenosomal function.In this report, we have investigated the ability of the four putative adhesins in binding to cells of different species and histologic derivations in an attempt to assess whether the recognition of a specific receptor in a particular cell type could be responsible for the well-known tissue specificity of the parasite. Different cell types, of human and nonhuman derivation, have been used: HeLa, CHO, and Vero cell lin...

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“…In addition, Fiori et al [14] also proposed a mechanism to explain that the hemolytic activity of T. vaginalis was a contact and temperature dependent phenomenon and hypothesised that cytopathic effects could be related to pore-forming in the membrane of erythrocytes. Multiple activities of cysteine proteinases (CP) have been found among parasitic protozoa [26], including T. foetus [24].…”

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confidence: 99%

Tritrichomonas foetus: a scanning electron microscopy study of erythrocyte adhesion associated with hemolytic activity

2004

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-The in vitro hemolytic activity of Tritrichomonas foetus was investigated. The parasite was tested against human erythrocytes of groups A, B, AB, and O, and against erythrocytes of nine adult animals of different species (the rabbit, rat, chicken, cat, dog, swine, horse, bovine, and sheep). The results showed that T. foetus strains (ATCC KV1, K, PAL, 5022, RJ, 90) did not present any hemolytic activity against any human erythrocyte group nor against rabbit, rat, chicken, cat, dog and swine erythrocytes. T. foetus strains, however, lysed horse, bovine, and sheep erythrocytes. No hemolysin released by the parasites could be identified. Hemolysis did not occur with trichomonad culture supernatants, with sonicated extracts of T. foetus, nor with killed organisms. Scanning electron microscopy (SEM) showed that human erythrocytes did not adhere to the trophozoites, in contrast horse erythrocytes adhered to the surface of the parasites and were phagocytosed for up to 90 min. The parasites are able to exert their cytopathic effects through: (a) physical contact established between the two cell surfaces, (b) toxins released from parasites into the interaction media, or (c) the association of both mechanisms. Further studies are necessary to clarify the importance of the hemolytic activity in the biology of T. foetus.Tritrichomonas foetus / hemolytic activity / scanning electron microscopy / erythrophagocytosis / cytopathic effects

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Trichomonas vaginalis haemolysis: Evidence of functional pores formation on red cell membranes

Cited by 25 publications

References 13 publications

Long-Term Survival and Intracellular Replication of Mycoplasma hominis in Trichomonas vaginalis Cells: Potential Role of the Protozoon in Transmitting Bacterial Infection

Long-Term Survival and Intracellular Replication of Mycoplasma hominis in Trichomonas vaginalis Cells: Potential Role of the Protozoon in Transmitting Bacterial Infection

Host and Tissue Specificity of Trichomonas vaginalis Is Not Mediated by Its Known Adhesion Proteins

Tritrichomonas foetus: a scanning electron microscopy study of erythrocyte adhesion associated with hemolytic activity

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