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Antigenicity of Trichomonas vaginalis heat-shock proteins in human infections.

Patients infected with Trichomonas vaginalis mount humoral and cellular immune responses that often do not protect against reinfection. The oxidative stressors produced by leukocytes may trigger a heat-shock-like response in T. vaginalis trophozoites, helping the parasite to survive host immune defenses. The antigenicity of T. vaginalis heat-shock proteins (HSPs) was examined by immunoprecipitation of T. vaginalis heat-induced proteins with sera from infected patients and controls. When T. vaginalis was heat-shocked, HSPs of 169-167 and 140-137 kDa were specifically recognized by sera from infected male and female patients. However, the majority of T. vaginalis HSPs were also immunoprecipitated by control sera; all sera recognized 72- to 71-kDa, 47- to 45-kDa, 38- to 37-kDa, 35-kDa, and 31-kDa heat-induced proteins. At least 15 proteins from non-heat-shocked T. vaginalis were immunoprecipitated by sera from infected patients and controls, indicating that natural or cross-reacting antibodies could participate in host responses to trichomoniasis. Molecules of 158, 135, 89, and 74-72 kDa were immunoprecipitated from some non-heat-shocked parasites only by patients' sera. A 38-kDa T. vaginalis protein was immunoprecipitated only by sera from infected females and may be specific for infection in women.

Animals↗

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 well established. Adhesion of T. vaginalis to human epithelial cells is considered a prerequisite for parasitic infection and its pathogenic effect. To investigate cytopathological changes in the host caused by T. vaginalis infection, human amnion membrane was used as an in vitro model. T. vaginalis strain WAA38 from axenic culture was allowed to interact with the epithelial layer of the human amnion membrane for 6 and 9 h. Structural changes resulting from the interaction between parasite and host cells were studied with transmission (TEM) and scanning (SEM) electron microscopy. Analysis of the electron microscope data showed that T. vaginalis established contact with the host cells as early as after 6 h of incubation; however, a close attachment of parasites to the epithelial cells occurred only after 9 h. Amoeboid T. vaginalis formed numerous cytoplasmic extensions and adhered to the epithelial cells mostly through the portions of their body opposite the undulating membrane. A dense network of microfilaments was seen at the site of contact between T. vaginalis and epithelial cells. Damaged and desquamated epithelial cells were seen with TEM and SEM only in the areas where parasites were in direct contact with target cells.

Amnion↗

Relationship of the virulence of Trichomonas vaginalis and the major histocompatibility complex in murine trichomonad infection.

A biological assay based upon the induction of abscesses in mice injected subcutaneously with Trichomonas vaginalis was shown to be a valid method for comparing the virulence of two isolates of T. vaginalis cultured from two patients, one suffering from severe vaginitis and the other exhibiting only mild disease. The data showed excellent correlation between the physical dimensions of abscesses in mice injected with each trichomonad isolate and the severity of vaginitis produced in the women from whom the isolates were obtained. The assay employed in our study incorporated measurement of the mean abscess volumes from day 1 to day 6 post-inoculation with T. vaginalis. We found that the abscess assay was clearly superior to a murine intraperitoneal assay for virulence evaluation of trichomonad isolates. We then used the murine abscess assay to determine the susceptibility of different strains of mice to infection with a virulent T. vaginalis isolate so as to test whether the genetic constitution of the host would influence the pathogenesis of the disease. BALB/c (H-2d) mice were susceptible to infection with T. vaginalis, but both CBA/CaH (H-2k) and BALB/c-H-2k mice were shown to be resistant. The quantitation of abscess formation in these inbred and congeneic resistant mouse strains demonstrates that the severity of infection with T. vaginalis is governed by genes mapping within the major histocompatibility complex.

Abscess↗

Cryosurvival of Trichomonas vaginalis during cryopreservation of human semen.

Despite a 90% cryosurvival of Trichomonas vaginalis in their growth medium trypticase yeast maltose (TYM) with DMSO, none of these parasites have previously been observed to survive during cryopreservation of infected human semen with glycerol (Andrologia 18, 323 (1986)). This could have been due to the failure of the culture method used to detect low numbers of survivors. The prospects of possible transmission of T. vaginalis by artificial insemination with cryobanked (-196 degrees C) semen prompted an investigation of the cryosurvival of this parasite in the presence of semen with the cryoprotectant glycerol, using a more sensitive culture method for viability evaluation. Semen and seminal fluid from the same 23 ejaculates, as well as culture medium, were inoculated with small clinical numbers of T. vaginalis and evaluated as to their survival before and after cryopreservation. Results indicated: (i) The highest cryosurvival of T. vaginalis (4.5%) was in cryobanked (glycerolated) semen, (ii) semen, as well as glycerol, shows cryoprotective action, and (iii) glycerol reduced survival of parasites in semen, seminal fluid, and TYM medium during exposure prior to freezing. Clinical information on infectivity of small numbers of T. vaginalis and the data presented here suggests that these organisms could be transmitted by artificial insemination with infected cryobanked human semen.

Animals↗

The relationship of experimental pathogenicity in vivo with in vitro cytoadherence and cytotoxicity of 6 different isolates of Trichomonas vaginalis.

The experimental pathogenic effects in vivo and in vitro of 6 different isolates of Trichomonas vaginalis were studied following their inoculation into NMRI mice and on to adherent cultures of HeLa cells. Contact between the parasite and the adherent monolayer of cells was necessary to induce the monolayer to detach. The strains which were more virulent to mice also showed a greater weighted index of adherence; the weighted index of cytotoxicity in vitro did not, on the other hand, correlate with experimental pathology in vivo.

Animals↗

Trichomonas vaginalis: alternative pathway activation of complement.

Serum from adult human donors lysed Trichomonas vaginalis. The lytic effect was eliminated by heat-inactivation of serum (56 degrees C, 30 min). No serum donor exhibited significantly increased antibody against the parasite as measured by indirect immunofluorescence. Treatment of serum with ethylene glycol-bis (B-aminoethyl ether)-N, N-tetraacetic acid to eliminate classical pathway complement activation did not prevent C3 leads to C3i conversion in serum incubated with T. vaginalis. Release of complement products during alternative pathway activation may contribute to pathogenesis of trichomonal vaginitis.

Adult↗

Trichomonas vaginalis and Tritrichomonas foetus secrete neuraminidase into the culture medium.

Supernatants taken from axenic cultures of Trichomonas vaginalis and Tritrichomonas foetus contain a neuraminidase activity, the detection of which is augmented when the trichomonad culture media are supplemented with 30% supernatant of confluent epithelial cultures. The enzyme was active against human erythrocytes, which became highly reactive to peanut agglutinin lectin. The specificity of the enzyme was checked by using a substrate specific to neuraminidase: 2'-(4-methylumbelliferyl)-alpha-D-N-acetylneuramic acid.

Animals↗

Pre-existing chronic infraepithelial Trichomonas invasion with consecutive immunodepression enables progression of human immunodeficiency virus: a new concept of acquired immunodeficiency syndrome pathogenesis.

All three existing species of human trichomonads cause similar immune and histopathological host responses. The elicited crossimmunity causes interspecific competition of trichomonal infections in their typical localizations, which results in very rare simultaneous colonization of the same host by different species. This phenomenon points to the existence of a unique immune disorder or subclinical sensitization, regardless of which trichomonas species is in question. The total percentage of infestations in all three species points to the most widespread parasitosis, i.e. the immunodepression of human beings. Trichomonaemia has a very strong immunodepressive action. All the other agents, including viruses act only as opportunists.

Acquired Immunodeficiency Syndrome↗

Selective elution and purification of living Trichomonas vaginalis using gravitational field-flow fractionation.

Gravitational field-flow fractionation is one of the simplest separation methods for biological materials. Its potential in parasitology is demonstrated for Trichomonas vaginalis, a parasite responsible for one of the most widespread sexually transmitted diseases. It was observed that this unicellular parasite can be purified in a culture medium with a recovery of 85% for the living trophozoites. The parasite retention characteristics were different when motile living and non-motile dead cells were eluted, motile cells being less retained than the non-motile cells.

Adult↗

Trichomonas vaginalis and cervical cancer. A prospective study in China.

The relationship between Trichomonas vaginalis infection and cervical cancer was investigated prospectively in a cohort of 16,797 women aged 25 years or more who were followed from 1974 to 1985 within the framework of a cervical screening program in Jingan, China. Personal interviews were conducted by trained interviewers when the women first entered the screening program. At initial screening, 421 (2.51%) women had a positive cytologic diagnosis of T. vaginalis infection. Ninety-nine incident cases of pathologically confirmed squamous cell carcinoma were identified from the cohort, with a total of 140,018 person-years of observation. T. vaginalis infection was found to contribute to the risk of cervical cancer, as determined by crude estimates and after adjustment for potential confounding effects. In a multiple proportional hazards model, the relative risk for cervical cancer was 3.3 (95% confidence interval: 1.5 to 7.4) among women with T. vaginalis infection. Furthermore, in the multivariate analysis, increased risk of cervical cancer was associated with the following factors: number of extramarital sexual partners of both the subjects and their spouses, cigarette smoking, and irregular menstruation. Having a large number of negative Pap smears was associated with lower risk. This study suggests that there might be an association between T. vaginalis infection and the risk of cervical cancer, but only 4 to 5% of cervical cancer in Chinese women may be attributable to T. vaginalis infection.

Adult↗

Is the presence of Trichomonas vaginalis a reliable predictor of coinfection with Chlamydia trachomatis and/or Neisseria gonorrhoeae in female ED patients?

OBJECTIVE: The aim of the study was to determine if the presence of Trichomonas vaginalis (TV) is associated with an increased risk of coinfection with Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (NG) in female patients presenting to the ED with symptoms consistent with a sexually transmitted disease (STD). METHODS: This was a retrospective observational study of female patients tested for the presence of TV by wet mount preparation in the ED from January 1998 through January 2001. Only patients that had the complete results of the wet preparation for TV, DNA probe for CT, and culture for NG were included. RESULTS: A total of 690 patients were enrolled in the study. Four hundred twenty (61%) patients tested positive for TV by wet mount preparation and 270 (39%) tested negative. Of the 420 TV-positive patients, 41 (9.8%) tested positive for NG, 35 (8.3%) tested positive for CT, and 16 (3.8%) for both. For the 270 TV-negative patients, 16 (5.9%) tested positive for NG, 91 (33.7%) tested positive for CT, and 16 (5.9%) for both. By chi 2 testing, there was a strong negative association between the presence of TV and coinfection with CT and/or NG. The presence of TV made it 2.9 times less likely to have coinfection with NG and/or CT. CONCLUSION: The presence of TV in female patients presenting to the ED with symptoms consistent with an STD is not associated with an increased risk of coinfection with NG and/or CT.

Animals↗

Apoptosis of macrophages induced by Trichomonas vaginalis through the phosphorylation of p38 mitogen-activated protein kinase that locates at downstream of mitochondria-dependent caspase activation.

Trichomonas vaginalis, a flagellated protozoan parasite, is the causative organism of trichomoniasis. We have recently demonstrated that T. vaginalis induces apoptotic cell death via a Bcl-x(L)-dependent pathway in RAW264.7 macrophages. In this study, we attempted to characterize in detail the signaling cascades resulting in T. vaginalis-induced macrophage apoptosis, focusing particularly on mitochondrial changes and the role of p38 mitogen-activated protein kinase (p38 MAPK) activation. We found that T. vaginalis induced mitochondrial changes including the release of cytochrome c and the serial activation of caspases, leading to the activation of p38 MAPK in macrophages. These biochemical changes culminated in the apoptosis of the host cells. Caspase inhibitors induced a significant inhibition of T. vaginalis-induced nuclear damage, as well as the activation of p38 MAPK. Treatment with the p38 MAPK inhibitor, SB203580, or the overexpression of kinase-inactive p38 MAPK, induced an attenuation of T. vaginalis-induced apoptosis but not cytochrome c release, the activation of caspase-9 and caspase-3, or PARP cleavage. Furthermore, SB203580 treatment to human macrophages consistently blocked T. vaginalis-induced apoptosis. Collectively, our findings indicate that p38 MAPK signaling cascade is requisite to apoptosis of T. vaginalis-infected macrophage, and this apoptotic process occurs via the phosphorylation of p38 MAPK, which is located downstream of mitochondria-dependent caspase activation, conferring insight into the plausible molecular mechanism of T. vaginalis-immune evasion from macrophage attack.

Animals↗

Trichomonas vaginalis infection activates cells through toll-like receptor 4.

While Trichomonas vaginalis infection can cause inflammation and influx of leukocytes into the female genital tract, the molecular pathways important in inducing these effects are not known. This study determined if infection with T. vaginalis activates cells through toll-like receptor 4 (TLR4). Genital tract secretions from infected women stimulated TNF-alpha production by cells with functional TLR4 (350 pg/ml) but significantly less by cells that are unresponsive to TLR4 ligands (44 pg/ml, P = 0.001). Secretions collected after clearance of infection also induced significantly lower responses by cells with functional TLR4 (136 pg/ml, P = 0.008). TNF-alpha responses were not reduced by Polymyxin B and did not correlate with beta(2)-defensin levels, indicating that stimulation of cells was not through lipopolysaccharide or beta(2)-defensin. These studies show that T. vaginalis infection results in the appearance in the genital tract of substance(s) that stimulate cells through TLR4, suggesting a mechanism for the inflammation caused by this infection.

Animals↗

Increased sensitivity of Trichomonas vaginalis isolation from vaginal secretions by subsequent blind passage of preliminary negative cultures.

Trichomonas vaginalis is a vaginal protozoon causing the most prevalent nonviral sexually transmitted disease. Culture is considered as the most reliable and gold standard among conventional diagnostic methods in the detection of T. vaginalis. In the present study, the diagnostic effect of subsequent blind culturing of vaginal secretion samples in Diamond's complete medium at every 48 h was investigated in 93 women. Vaginal secretion samples were examined by wet mount and inoculated into Diamond's complete medium. All tubes were subcultured to a new culture tube blindly 5 times at 48-h interval and checked microscopically everyday for the presence of T. vaginalis trophozoites. Three of 93 women were found to be positive both by wet mount and standard culture methods. Five more positive results were detected with subsequent blind culturing among 90 negative results. This system appears to be a useful method for the detection of T. vaginalis.

Adolescent↗

Diagnosis of Trichomonas vaginalis infection: The sensitivities and specificities of microscopy, culture and PCR assay.

OBJECTIVES: The aim of this study was to compare wet mount-, Giemsa stain-, acridine orange fluorescent stain-, cultivation- and polymerase chain reaction (PCR)-based approaches to establish which method or combination of methods was most effective in the laboratory diagnosis of trichomoniasis. STUDY DESIGN: Out of 200 investigated patients with various gynecological complaints, Trichomonas vaginalis infection was detected in 27 (13.5%) by any of methods investigated. Among women with trichomonads, a typical clinical finding was presented in only nine. For analysis of sensitivity and specificity of the methods used, the receiver operating characteristic (ROC) curve concept with culture as a gold standard was applied. RESULTS: Infection was diagnosed by wet mount in 14 (7.0%) women, by Giemsa stain in 11 (5.5%) and by acridine orange stain in 16 (8.0%) women. In 21 (10.5%) women, it was diagnosed by culture in Diamond's medium, and in 22 (11.0%) by PCR. For the initial diagnosis of trichomoniasis, wet preparation is the test that is widely available in most STD clinics, but its sensitivity is poor (66.67%). Giemsa stain shows a low sensitivity of 52.38%. Acridine orange shows reasonable sensitivity and specificity of 71.43% and 99.44%, respectively. The sensitivity and specificity of PCR (80.95% and 97.21%) did not exceed that of culture. CONCLUSION: With regard to the fact that trichomoniasis can have an atypical or even asymptomatic course, in order to accurately diagnose this disease, microbiological investigation is necessary. Comparison of different methods showed that at least two techniques, such as culture and acridine orange staining, have the potential for better diagnosis of T. vaginalis infection. PCR detection of infection has been demonstrated to be highly specific and sensitive, but its availability and cost effectiveness are in question. PCR could provide an alternative for laboratory diagnosis of trichomoniasis by culture.

Adult↗

Trichomonas vaginalis: characterization of a 39-kDa cysteine proteinase found in patient vaginal secretions.

Trichomonosis, a chronic sexually transmitted disease, remains a public health problem affecting yearly over 170 million people worldwide. This disease is caused by Trichomonas vaginalis, a protozoan flagellate rich in cysteine proteinases (CPs). Although CPs are involved in trichomonal cytopathogenicity, only few of them have been defined as virulence factors. In this study, we characterize a T. vaginalis 39-kDa proteinase (CP39) found in vaginal secretions from patients with trichomonosis. The CP39 proteinase bound to HeLa epithelial cells, vaginal epithelial cells (VECs), and human prostatic cancer cells (DU-145). CP39 did not bind to a human colon cancer (CaCo) cell line, suggesting tissue-specific binding. CP39 was found in six fresh trichomonad isolates tested. In two-dimensional gels, CP39 appeared as a single spot with a pI 4.5. CP39 is inhibited by E-64, stable at 50 degrees C, and active in a wide pH range (3.6-9.0), with an optimum pH at 7.0. In addition, CP39 degraded collagens I, III, IV, and V, human fibronectin, human hemoglobin, and human immunoglobulins A and G. Indirect immunofluorescence detected CP39 on the parasite surface with specific polyclonal antibody to purified CP39. Finally, CP39 was found to be immunogenic, as evidenced by detection on immunoblots with serum of patients with trichomonosis, but not control individuals. These data suggest that CP39 may play a role during trichomonal infection.

Animals↗

Trichomonas vaginalis: intrastrain polymorphisms within the ribosomal intergenic spacer do not correlate with clinical presentation.

Trichomoniasis presents a broad spectrum of clinical patterns ranging from asymptomatic to severe vaginitis and cervicitis. Despite its importance, very little is known about the genetic relatedness of its causative agent, Trichomonas vaginalis, and the clinical phenotypes. To address this question, analysis of restriction length polymorphism (RFLP) within the intergenic spacer of the ribosomal DNA (IGS) from 60 clinically defined isolates of T. vaginalis was performed. This is the first description of the IGS polymorphism of T. vaginalis. As expected, a considerable number of patients were asymptomatic (28%) while only 12% presented both leukorrhea and macular colpitis, the most evident symptoms of trichomoniasis. The IGS-RFLP with the use of eight restriction enzymes showed absence of correlation between the genetic relatedness of the isolates and symptomatology. Further studies are necessary to evaluate the importance of the IGS polymorphism to the parasite virulence and clinical phenotype.

Animals↗

Genetic variability between Trichomonas vaginalis isolates and correlation with clinical presentation.

The random amplified polymorphic DNA (RAPD) technique was used to determine genetic differences among isolates of Trichomonas vaginalis and these genetic data were correlated with patient records. A panel of 10 random primers was used to determine the type and extent of intraspecific polymorphism in 40 isolates of T. vaginalis. All primers detected DNA polymorphism among isolates. Numerical analysis of 124 RAPD amplified bands generated by these 10 primers were carried out with the unweighted pair group methods analysis (UPGMA) using Jaccard's Similarity Coefficient and data were used to construct a dendrogram. Four main groups can be distinguished by RAPD data, these groups coincide with four different patient categories (asymptomatic and symptomatic: light, moderate, and severe infection). These patients did not have any concomitant vaginal infection. Each of the four groups can be characterized by specific genetic markers, but a specific 490bp marker was found to be specific for all symptomatic isolates, not the asymptomatic isolates. This is the first description of a possible virulence marker for T. vaginalis. Further studies will be necessary to ascertain the importance and function of this genetic marker in clinical infection.

Adolescent↗