Cytopathogenic effect of Trichomonas vaginalis on human vaginal epithelial cells cultured in vitro

The L-Rhamnose Biosynthetic Pathway in Trichomonas vaginalis: Identification and Characterization of UDP-D-Glucose 4,6-dehydratase

Trichomonas vaginalis is the causative agent of one of the most widespread sexually transmitted diseases in the world. The adhesion of the parasite to the vaginal epithelial cells is mediated by specific proteins and by a complex glycan structure, the lipoglycan (TvLG), which covers the pathogen surface. L-rhamnose is an important component of TvLG, comprising up to 40% of the monosaccharides. Thus, the inhibition of its production could lead to a severe alteration in the TvLG structure, making the L-rhamnose biosynthetic pathway an attractive pharmacologic target. We report the identification and characterization of the first committed and limiting step of the L-rhamnose biosynthetic pathway, UDP-D-glucose 4,6-dehydratase (UGD, EC 4.2.1.76). The enzyme shows a strong preference for UDP-D-glucose compared to dTDP-D-glucose; we propose that the mechanism underlying the higher affinity for the UDP-bound substrate is mediated by the differential recognition of ribose versus the deoxyribose of the nucleotide moiety. The identification of the enzymes responsible for the following steps of the L-rhamnose pathway (epimerization and reduction) was more elusive. However, sequence analyses suggest that in T. vaginalis L-rhamnose synthesis proceeds through a mechanism different from the typical eukaryotic pathways, displaying intermediate features between the eukaryotic and prokaryotic pathways and involving separate enzymes for the epimerase and reductase activities, as observed in bacteria. Altogether, these results form the basis for a better understanding of the formation of the complex glycan structures on TvLG and the possible use of L-rhamnose biosynthetic enzymes for the development of selective inhibitors.

Characterisation of Trichomonas vaginalis Isolates Collected from Patients in Vienna between 2019 and 2021

Trichomonas vaginalis (TV) is the causative agent of trichomoniasis, the most common nonviral sexually transmitted disease. TV can carry symbionts such as Trichomonas vaginalis virus (TVV) or Mycoplasma hominis. Four distinct strains of TV are known: TVV1, TVV2, TVV3, and TVV4. The aim of the current study was to characterise TV isolates from Austrian patients for the presence of symbionts, and to determine their effect on metronidazole susceptibility and cytotoxicity against HeLa cells. We collected 82 TV isolates and detected presence of TVV (TVV1, TVV2, or TVV3) in 29 of them (35%); no TVV4 was detected. M. hominis was detected in vaginal/urethral swabs by culture in 37% of the TV-positive patients; M. hominis DNA was found in 28% of the TV isolates by PCR. In 15% of the patients, M. hominis was detected in the clinical samples as well as within the respective TV isolates. In 22% of the patients, M. hominis was detected by culture only. In 11 patients, M. hominis was detected only within the respective cultured TV isolates (13%), while the swab samples were negative for M. hominis. Our results provide a first insight into the distribution of symbionts in TV isolates from Austrian patients. We did not observe significant effects of the symbionts on metronidazole susceptibility, cytotoxicity, or severity of symptoms.

Local cytokine/chemokine profiles in BALB/c and C57BL/6 mice in response to T. vaginalis infection

Trichomonas vaginalis is the causative agent of Trichomoniasis (a sexually transmitted infection). Recent reports have shown that stimulation of cellular immunity can reduce trichomoniasis infection. Animal studies are essential to understanding the pathogenesis of infection and developing new potential drugs and vaccines to treat the infection. Therefore, we have tried to understand the pathogenesis of T. vaginalis infection by investigating the differences in the expression of chemokine/cytokine levels in vaginal and cervical tissues of BALB/c and C57BL/6 mice. Different pathological symptoms, like desquamation, neutrophil infiltration, and hemorrhage, were recorded in BALB/c and C57BL/6 in response to T. vaginalis infection. Vaginal and cervical tissues of BALB/c showed these symptoms on 2nd dpi, which became severe on 7th dpi and turned to mild or normal till 14th dpi compared to C57BL/6 strain. Immunohistochemistry in the vagina and cervical tissues of BALB/c and C57BL/6 mice was done to assess cytokines at different time intervals post-infection. Significant expression of Interleukin-1β (IL-1β) (a pro-inflammatory cytokine) was found in BALB/c compared to the C57BL/6 mice, on 7th dpi and 2nd dpi in vaginal and cervical tissues, respectively. Higher expression of MIP-2 (neutrophil chemoattractant) was observed in the vaginal tissues of BALB/c mice on 7th dpi compared to the C57BL/6 group. In addition, higher expression of TGF-β (immune-suppressor) was observed on 7th dpi in the vaginal tissue of BALB/c mice. The present study demonstrates that more pathological signs of T. vaginalis infection developed in BALB/c mice than C57BL/6 mice. Also, significant levels of IL-1β and MIP-2 were measured in BALB/c mice in response to T. vaginalis compared to C57BL/6.

Protozoan-Viral-Bacterial Co-Infections Alter Galectin Levels and Associated Immunity Mediators in the Female Genital Tract

Co-infections with sexually transmittable pathogens are common and more likely in women with disturbed vaginal bacteriome. Among those pathogens, the protozoan parasite Trichomonas vaginalis (TV) is most common after accounting for the highly persistent DNA viruses human papillomavirus (HPV) and genital herpes. The parasitic infection often concurs with the dysbiotic syndrome diagnosed as bacterial vaginosis (BV) and both are associated with risks of superimposed viral infections. Yet, the mechanisms of microbial synergisms in evading host immunity remain elusive. We present clinical and experimental evidence for a new role of galectins, glycan-sensing family of proteins, in mixed infections. We assessed participants of the HIV Epidemiology Research Study (HERS) at each of their incident TV visits (223 case visits) matched to controls who remained TV-negative throughout the study. Matching criteria included age, race, BV (by Nugent score), HIV status, hysterectomy, and contraceptive use. Non-matched variables included BV status at 6 months before the matched visit, and variables examined at baseline, within 6 months of and/or at the matched visit e.g. HSV-2, HPV, and relevant laboratory and socio-demographic parameters. Conditional logistic regression models using generalized estimating equations calculated odds ratios (OR) for incident TV occurrence with each log₁₀ unit higher cervicovaginal concentration of galectins and cytokines. Incident TV was associated with higher levels of galectin-1, galectin-9, IL-1β and chemokines (ORs 1.53 to 2.91, p <0.001). Galectin-9, IL-1β and chemokines were up and galectin-3 down in TV cases with BV or intermediate Nugent versus normal Nugent scores (p <0.001). Galectin-9, IL-1β and chemokines were up in TV-HIV and down in TV-HPV co-infections. In-vitro, TV synergized with its endosymbiont Trichomonasvirus (TVV) and BV bacteria to upregulate galectin-1, galectin-9, and inflammatory cytokines. The BV-bacterium Prevotella bivia alone and together with TV downregulated galectin-3 and synergistically upregulated galectin-1, galectin-9 and IL-1β, mirroring the clinical findings of mixed TV–BV infections. P. bivia also downregulated TVV+TV-induced anti-viral response e.g. IP-10 and RANTES, providing a mechanism for conducing viral persistence in TV-BV co-infections. Collectively, the experimental and clinical data suggest that galectin-mediated immunity may be dysregulated and exploited by viral–protozoan–bacterial synergisms exacerbating inflammatory complications from dysbiosis and sexually transmitted infections.

PCR Detection and Sequencing of Trichomonas vaginalis in Women with Suspected Vaginitis in Southwestern Iran

INTRODUCTION

The human being is considered a natural host for Trichomonas vaginalis (T. vaginalis), which causes trichomoniasis, the most frequent non-viral sexually transmitted infectious disease in the world. The current study aimed to evaluate the prevalence and sequencing of T. vaginalis in women with vaginitis. ; Methods: In the current research, 514 vaginal discharge samples were obtained from women with vaginitis. The specimens were evaluated by the direct wet mount examination, Dorset culture medium, and PCR technique. Primers were designed for the detection of TVK3/TVK7, TVA5/TVA6 genes specific for the identification of T. vaginalis. The PCR-positive samples were sequenced and compared with the sequences registered in the GenBank database. ; Results: Among the collected samples, 30 (5.83%), 45 (8.75%), 90 (17.50%), and 62 (12.06%) cases were positive for T. vaginalis when assayed by the direct wet mount examination, Dorset culture medium, and PCR technique (TVK3/TVK7, TVA5/TVA6 genes), respectively. There was no significant relationship between trichomoniasis and demographic characteristics of women, such as age, occupational status, mode of delivery, number of deliveries, educational level, and contraceptive methods (p˃0.05). The range of vaginal pH was between 5-7 in women with vaginitis, and there was a significant statistical correlation between the pH values and the infection rate (p<0.05). The PCR-positive samples had 100% sequence homology with the reference sequence in the GenBank database (accession number L23861.1). ; Conclusion: This study confirmed a relatively high prevalence of T. vaginalis in the southwestern region of Iran. According to our results, the PCR method, especially detecting TVK3/TVK7 genes, was more sensitive than the direct wet mount examination and Dorset culture medium methods.

Demonstration and Characterization of Cyst-Like Structures in the Life Cycle of Trichomonas vaginalis

Trichomonas vaginalis is the parasitic protozoan residing in human urogenital tract causing trichomoniasis, which is the leading non-viral sexually transmitted disease. It has cosmopolitan distribution throughout the globe and affects both men and women. Lifecycle of the parasite has been traditionally described as consisting of motile and symptom-causing trophozoites. Chemical and temperature perturbations in trophozoites have been shown to aid conversion to pseudocysts, which is poorly investigated. In the current study, we show the formation of viable cyst-like structures (CLS) in stationary phase of T. vaginalis axenic culture. We used a fluorescent stain called calcofluor white, which specifically binds to chitin and cellulose-containing structures, to score for T. vaginalis CLS. Using flow cytometry, we demonstrated and quantitated the processes of encystation as well as excystation; thus, completing the parasite's lifecycle in vitro without any chemical/temperature alterations. Like cysts from other protozoan parasites such as Entamoeba histolytica and Giardia lamblia, T. vaginalis CLS appeared spherical, immotile, and resistant to osmotic lysis and detergent treatments. Ultrastructure of CLS demonstrated by Transmission Electron Microscopy showed a thick electron-dense deposition along its outer membrane. To probe the physiological role of CLS, we exposed parasites to vaginal pH and observed that trophozoites took this as a cue to convert to CLS. Further, upon co- culturing with cells of cervical origin, CLS rapidly excysted to form trophozoites which abrogated the cervical cell monolayer in a dose-dependent manner. To further corroborate the presence of two distinct forms in T. vaginalis, we performed two-dimensional gel electrophoresis and global, untargeted mass spectrometry to highlight differences in the proteome with trophozoites. Interestingly, CLS remained viable in chlorinated swimming pool water implicating the possibility of its role as environmentally resistant structures involved in non-sexual mode of parasite transmission. Finally, we showed that symptomatic human patient vaginal swabs had both T. vaginalis trophozoites and CLS; thus, highlighting its importance in clinical infections. Overall, our study highlights the plasticity of the pathogen and its rapid adaption when subjected to stressful environmental cues and suggests an important role of CLS in the parasite's life cycle, pathogenesis and transmission.

Efficacy of netropsin dihydrochloride against the viability, cytopathogenicity and hemolytic activity of Trichomonas vaginalis clinical isolates

Trichomonas vaginalis (T. vaginalis) is a common sexually transmitted infection, affecting the urogenital tract. Trichomoniasis is customarily treated with metronidazole (MTZ). MTZ is known to cause undesirable side effects and there is several reports on MTZ resistant T. vaginalis. Thus, the present study aimed to in-vitro evaluate the activity of DNA minor groove binder drug ''Netropsin dihydrochloride'' against metronidazole-sensitive T. vaginalis isolates (G and U isolates) and resistant T. vaginalis isolate (ATCC50138) (R isolate). Netropsin was tested at concentrations ranging from 3.5 to 200 μg/ml. It showed effectiveness against all isolates with MLC of 12.5 μg/ml for G and U isolates and of 25 μg/ml for R isolate. Cytotoxicity assay of isolates exposed to the respective MLC of netropsin for 42 h showed a highly significant reduction in the death percentage of MCDK cell line as compared to the effect elicited by drug free controls. The hemolytic activity was evaluated by hemolytic assay and by monitoring the interaction of T. vaginalis isolates with human erythrocytes by inverted microscopy and scanning electron microscopy. The hemolytic assay showed (0%) hemolysis of RBCs incubated with T. vaginalis isolates treated with the corresponding MLC of netropsin for 24 h. Scanning electron microscopy revealed cytoskeletal deformities of netropsin treated isolates. Taken together, these observations suggest that netropsin is a promising therapy for T. vaginalis infection affecting its viability, virulence, cytopathogenic and hemolytic activity with a mechanism of action that might overcome T. vaginalis resistance to metronidazole.

Lactobacillus crispatus accelerates re-epithelialization in vaginal epithelial cell line MS74

PROBLEM

The functions of vaginal lactobacilli in susceptibility to infectious diseases as regards epithelial barrier integrity and wound healing remain incompletely understood.

METHOD OF STUDY

Lactobacillus crispatus, one of the most common Lactobacillus species in the vagina and among the most protective against sexually transmitted infections, was cocultured with an immortalized human vaginal epithelial cell line (MS74), and a scratch assay was performed to evaluate re-epithelialization. The concentration of vascular endothelial growth factor A (VEGF) was measured using enzyme-linked immunosorbent assay (ELISA). An immunofluorescence assay was performed to locate the expression of VEGF and VEGF receptor (VEGFR) 1 and 2. The effects of the bacterial supernatant of L. crispatus were also evaluated.

RESULTS

Lactobacillus crispatus significantly accelerated re-epithelialization of MS74 cells, accompanied by an increase in VEGF concentration. In contrast, heat-killed L. crispatus did not show this effect. The bacterial supernatant of L. crispatus also induced re-epithelialization. The immunoreactivity of VEGF was higher at the scratched edge, whereas VEGFR1 and 2 stained site-independently. Recombinant VEGF induced cell migration in a dose-dependent manner. The bacterial supernatant of L. crispatus also significantly accelerated re-epithelialization in MS74 cells and increased the concentration of VEGF in the culture 24 hours after the scratch.

CONCLUSION

These results may enhance our knowledge of the importance of L. crispatus in the healing of damaged vaginal epithelium and protection against the consequent risk of pathogenic infections, such as human immunodeficiency virus (HIV), and improve our understanding of vaginal epithelial barrier integrity maintenance by this bacterium.

Trichomonicidal and parasite membrane damaging activity of bidesmosic saponins from Manilkara rufula

The infection caused by Trichomonas vaginalis is the most common but overlooked non-viral sexually transmitted disease worldwide. Treatment relies on one class of drugs, the 5-nitroimidazoles, but resistance is widespread. New drugs are urgently needed. We reported the effect of crude and purified saponin fractions of Manilkara rufula against Trichomonas vaginalis. The compound responsible for antitrichomonal activity was isolated and identified as an uncommon bidesmosic saponin, Mi-saponin C. This saponin eliminated parasite viability without toxicity against the human vaginal epithelial line (HMVII). In addition, the isolated saponin fraction improved the metronidazole effect against a metronidazole-resistant isolate and dramatically reduced the cytoadherence of T. vaginalis to human cells. Investigation of the mechanism of death showed that the saponin fraction induced the parasite death due to profound membrane damage, inducing a disturbance of intracellular content without nuclear damage. To the best of our knowledge, this is the first report of antitrichomonal activity in the bidesmosic saponins of Manilkara rufula.

SNAP23-Dependent Surface Translocation of Leukotriene B4 (LTB4) Receptor 1 Is Essential for NOX2-Mediated Exocytotic Degranulation in Human Mast Cells Induced by Trichomonas vaginalis-Secreted LTB4

Trichomonas vaginalis is a sexually transmitted parasite that causes vaginitis in women and itself secretes lipid mediator leukotriene B₄ (LTB₄). Mast cells are important effector cells of tissue inflammation during infection with parasites. Membrane-bridging SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complexes are critical for fusion during exocytosis. Although T. vaginalis-derived secretory products (TvSP) have been shown to induce exocytosis in mast cells, information regarding the signaling mechanisms between mast cell activation and TvSP is limited. In this study, we found that SNAP23-dependent surface trafficking of LTB₄ receptor 1 (BLT1) is required for nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2)-mediated exocytotic degranulation of mast cells induced by TvSP. First, stimulation with TvSP induced exocytotic degranulation and reactive oxygen species (ROS) generation in HMC-1 cells. Next, TvSP-induced ROS generation and exocytosis were strongly inhibited by transfection of BLT1 small interfering RNA (siRNA). TvSP induced trafficking of BLT1 from the cytosol to the plasma membrane. We also found that knockdown of SNAP23 abrogated TvSP-induced ROS generation, exocytosis, and surface trafficking of BLT1 in HMC-1 cells. By coimmunoprecipitation, there was a physical interaction between BLT1 and SNAP23 in TvSP-stimulated HMC-1 cells. Taken together, our results suggest that SNAP23-dependent surface trafficking of BLT1 is essential for exocytosis in human mast cells induced by T. vaginalis-secreted LTB₄ Our data collectively demonstrate a novel regulatory mechanism for SNAP23-dependent mast cell activation of T. vaginalis-secreted LTB₄ involving surface trafficking of BLT1. These results can help to explain how the cross talk mechanism between parasite and host can govern deliberately tissue inflammatory responses.

Trichomonas vaginalis: a possible foe to prostate cancer

Prostate cancer (PCA) is the most common malignancy in men in USA, and the role of Trichomonas vaginalis (T. vag) in the development of PCA is still controversial. Clonogenic assay, PCNA staining, TUNEL staining and caspase-3 activity assay were used to investigate the in vitro role of T. vag in human prostate cancer. We further investigated the possible molecular mechanisms using RT-PCR and immunohistochemical staining. Culture supernatant of T. vag inhibits growth of PC-3 prostate cancer cells, and this correlated with upregulation of p21. Culture supernatant of T. vag induced apoptosis of PC-3 cells, and this correlated with downregulation of Bcl-2. The growth inhibition effect of culture supernatant of T. vag is also demonstrated in another prostate cancer cell line DU145, suggesting that its effect is not specific to one prostate cancer cell line. Culture supernatant of T. vag inhibits growth of prostate cancer by inhibition of proliferation and promotion of apoptosis. Such a study might be helpful to address the association between PCA and infection of T. vag.

Bulky Trichomonad Genomes: Encoding a Swiss Army Knife

The trichomonads are a remarkably successful lineage of ancient, predominantly parasitic protozoa. Recent molecular analyses have revealed extensive duplication of certain genetic loci in trichomonads. Consequently, their genomes are exceptionally large compared to other parasitic protozoa. Retention of these large gene expansions across different trichomonad families raises the question: do these duplications afford an advantage? Many duplicated genes are linked to the parasitic lifestyle and some are regulated differently to their paralogues, suggesting they have acquired new functions. It is proposed that these large genomes encode a Swiss army knife of sorts, packed with a multitude of tools for use in many different circumstances. This may have bestowed trichomonads with the extraordinary versatility that has undoubtedly contributed to their success.

Trichomonas vaginalis Lipophosphoglycan Exploits Binding to Galectin-1 and -3 to Modulate Epithelial Immunity

Trichomoniasis is the most common non-viral sexually transmitted infection caused by the vaginotropic extracellular protozoan parasite Trichomonas vaginalis. The infection is recurrent, with no lasting immunity, often asymptomatic, and linked to pregnancy complications and risk of viral infection. The molecular mechanisms of immune evasion by the parasite are poorly understood. We demonstrate that galectin-1 and -3 are expressed by the human cervical and vaginal epithelial cells and act as pathogen-recognition receptors for the ceramide phosphoinositol glycan core (CPI-GC) of the dominant surface protozoan lipophosphoglycan (LPG). We used an in vitro model with siRNA galectin knockdown epithelial clones, recombinant galectins, clinical Trichomonas isolates, and mutant protozoan derivatives to dissect the function of galectin-1 and -3 in the context of Trichomonas infection. Galectin-1 suppressed chemokines that facilitate recruitment of phagocytes, which can eliminate extracellular protozoa (IL-8) or bridge innate to adaptive immunity (MIP-3α and RANTES (regulated on activation normal T cell expressed and secreted)). Silencing galectin-1 increased and adding exogenous galectin-1 suppressed chemokine responses to Trichomonas or CPI-GC/LPG. In contrast, silencing galectin-3 reduced IL-8 response to LPG. Live Trichomonas depleted the extracellular levels of galectin-3. Clinical isolates and mutant Trichomonas CPI-GC that had reduced affinity to galectin-3 but maintained affinity to galectin-1 suppressed chemokine expression. Thus via CPI-GC binding, Trichomonas is capable of regulating galectin bioavailability and function to the benefit of its parasitic survival. These findings suggest novel approaches to control trichomoniasis and warrant further studies of galectin-binding diversity among clinical isolates as a possible source for symptom disparity in parasitic infections.

Activation of MAPK Is Required for ROS Generation and Exocytosis in HMC-1 Cells Induced by Trichomonas vaginalis-Derived Secretory Products

Trichomonas vaginalis is a flagellated protozoan parasite that causes vaginitis and cervicitis in women and asymptomatic urethritis and prostatitis in men. Mast cells have been reported to be predominant in vaginal smears and vaginal walls of patients infected with T. vaginalis. Mitogen-activated protein kinase (MAPK), activated by various stimuli, have been shown to regulate the transcriptional activity of various cytokine genes in mast cells. In this study, we investigated whether MAPK is involved in ROS generation and exocytotic degranulation in HMC-1 cells induced by T. vaginalis-derived secretory products (TvSP). We found that TvSP induces the activation of MAPK and NADPH oxidase in HMC-1 cells. Stimulation with TvSP induced phosphorylation of MAPK and p47^phox in HMC-1 cells. Stimulation with TvSP also induced up-regulation of CD63, a marker for exocytosis, along the surfaces of human mast cells. Pretreatment with MAPK inhibitors strongly inhibited TvSP-induced ROS generation and exocytotic degranulation. Finally, our results suggest that TvSP induces intracellular ROS generation and exocytotic degranulation in HMC-1 via MAPK signaling.

Trichomonas vaginalis infection among Iranian general population of women: a systematic review and meta-analysis

Trichomonas vaginalis (T. vaginalis) is one of the main causes of vaginitis, prostatitis, and cervicitis all over the world. Little information is available regarding the burden of T. vaginalis infection in Iranian women. This systematic review and meta-analysis were carried out to determine the prevalence of T. vaginalis among general population of Iranian women. Data were systematically collected from 1992 to 2012 in Iran on such electronic databases as PubMed, Google Scholar, Science Direct, Scopus, Web of Science, Magiran, Irandoc, Iran medex, Scientific Information Database (SID), Global Health, and LILACS. Additionally, abstracts of national scientific congresses and dissertations were included. A total of 30 articles attempted to examine 70,373 individuals and reported the prevalence of trichomoniasis from different regions of Iran. The overall prevalence rate of trichomoniasis in Iran was estimated to be 8% (95% confidence interval (CI) = 0.07 to 0.09) with the maximum 38.8% (95% CI = 0.036 to 0.042) and the minimum 0.009% (95% CI = 0.008 to 0.010), respectively. Also, it was found that the prevalence in Central provinces is higher than other ones. In all studies, the average of age was 24.5 with the maximum and the minimum of 45 and 22.5 years old, respectively. The present review revealed that infection rate is relatively high among Iranian women, and risk factors such as hygienic situation, behavior and local culture, poor socioeconomic condition, feeble moral considerations, and increase in marriage age must be considered in the management of controlling programs.

Is Trichomonas tenax a Parasite or a Commensal?

Trichomonas tenax is considered a commensal organism found under poor oral hygiene conditions. T. tenax presents morphological similarities with T. vaginalis, and there are doubts concerning whether this protist is a parasite and whether it is a genetic variant of T. vaginalis. This study aimed to investigate the capacity of T. tenax to cause mammalian cell damage and compare its cytotoxicity with that of T. vaginalis. Protozoan-host cell interaction assays were performed with Madin-Darby canine kidney, HeLa, and gum cells and 3D spheroids, which were examined by scanning electron and transmission electron microscopy. Cellular viability experiments were also performed. T. tenax attached and had different forms when interacting with mammalian cells and caused damage with time-dependent host-cell viability. We observed that T. tenax produced plasma membrane projections and phagocytosed portions of the mammalian cells. In addition, T. tenax caused membrane blebbing and apoptotic bodies in HeLa cells, thus inducing cell death. Spheroids were also used in interaction assays with T. tenax and they were damaged by these cells. This study shows that T. tenax fulfills the requisites of a parasite, causing damage to different mammalian cells and behaving similarly to T. vaginalis when in contact with target cells in vitro.

The Marine Biological Laboratory (Woods Hole) and the scientific advancement of women in the early 20th century: the example of Mary Jane Hogue (1883-1962)

The Marine Biological Laboratory (MBL) in Woods Hole, MA provided opportunities for women to conduct research in the late 19th and early 20th century at a time when many barriers existed to their pursuit of a scientific career. One woman who benefited from the welcoming environment at the MBL was Mary Jane Hogue. Her remarkable career as an experimental biologist spanned over 55 years. Hogue was born into a Quaker family in 1883 and received her undergraduate degree from Goucher College. She went to Germany to obtain an advanced degree, and her research at the University of Würzburg with Theodor Boveri resulted in her Ph.D. (1909). Although her research interests included experimental embryology, and the use of tissue culture to study a variety of cell types, she is considered foremost a protozoologist. Her extraordinary demonstration of chromidia (multiple fission) in the life history of a new species of Flabellula associated with diseased oyster beds is as important as it is ignored. We discuss Hogue's career path and her science to highlight the importance of an informal network of teachers, research advisors, and other women scientists at the MBL all of whom contributed to her success as a woman scientist.

Trichomonas vaginalis induces cytopathic effect on human lung alveolar basal carcinoma epithelial cell line A549

Trichomonas vaginalis, the causative agent of trichomoniasis is generally known to inhabit the genitourinary tract. However, several case reports with supporting molecular and immunological identifications have documented its occurrence in the respiratory tract of neonates and adults. In addition, the reports have documented that its occurrence is associated with respiratory failures. The medical significance or consequence of this association is unclear. Thus, to establish the possible outcome from the interaction of T. vaginalis with lung cells, the cytopathic effects of the parasites were evaluated using monolayer cultures of the human lung alveolar basal carcinoma epithelial cell line A549. The possible effect of association of T. vaginalis with A549 epithelial cells was analyzed using phase-contrast, scanning electron microscopy and fluorescence microscopy. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), crystal-violet and TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling) assays were conducted for cytotoxicity testing. The results demonstrate that T. vaginalis: (1) adheres to A549 epithelial cells, suggesting a density-dependent parasite-cell association; (2) adherence on A549 is through flagella, membrane and axostyle; (3) causes cell detachment and cytotoxicity (50-72.4%) to A549 and this effect is a function of parasite density; and (4) induces apoptosis in A549 about 20% after 6 h of incubation. These observations indicate that T. vaginalis causes cytopathic effects on A549 cell. To date, this is the first report showing a possible interaction of T. vaginalis with the lung cells using A549 monolayer cultures. Further studies are recommended to completely elucidate this association.

Cysteine protease activity of feline Tritrichomonas foetus promotes adhesion-dependent cytotoxicity to intestinal epithelial cells

Trichomonads are obligate protozoan parasites most renowned as venereal pathogens of the reproductive tract of humans and cattle. Recently, a trichomonad highly similar to bovine venereal Tritrichomonas foetus but having a unique tropism for the intestinal tract was recognized as a significant cause of colitis in domestic cats. Despite a high prevalence, worldwide distribution, and lack of consistently effective drugs for treatment of the infection, the cellular mechanisms of T. foetus pathogenicity in the intestinal tract have not been examined. The aims of this study were to determine the pathogenic effect of feline T. foetus on porcine intestinal epithelial cells, the dependence of T. foetus pathogenicity on adhesion of T. foetus to the intestinal epithelium, and the identity of mediators responsible for these effects. Using an in vitro coculture approach to model feline T. foetus infection of the intestinal epithelium, these studies demonstrate that T. foetus promotes a direct contact-dependent activation of intestinal epithelial cell apoptosis signaling and progressive monolayer destruction. Moreover, these pathological effects were demonstrated to be largely dependent on T. foetus cell-associated cysteine protease activity. Finally, T. foetus cysteine proteases were identified as enabling cytopathic effects by promoting adhesion of T. foetus to the intestinal epithelium. The present studies are the first to examine the cellular mechanisms of pathogenicity of T. foetus toward the intestinal epithelium and support further investigation of the cysteine proteases as virulence factors in vivo and as potential therapeutic targets for ameliorating the pathological effects of intestinal trichomonosis.

Genetic predictors of cervical dysplasia in African American HIV-infected women: ACTG DACS 268

OBJECTIVE

To examine genome-wide associations in HIV-infected women with a history of cervical dysplasia compared with HIV-infected women with no history of abnormal Papanicolaou (Pap) tests.

DESIGN

Case-control study using data from women analyzed for the HIV Controllers Study and enrolled in HIV treatment-naïve studies in the AIDS Clinical Trials Group (ACTG).

METHODS

Genotyping utilized Illumina HumanHap 650 Y or 1MDuo platforms. After quality control and principal component analysis, ~610,000 significant single nucleotide polymorphisms (SNPs) were tested for association. Threshold for significance was P < 5 × 10(-8) for genome-wide associations.

RESULTS

No significant genomic association was observed between women with low-grade dysplasia and controls. The genome-wide association study (GWAS) analysis between women with high-grade dysplasia or invasive cervical cancer and normal controls identified significant SNPs. In the analyses limited to African American women, 11 SNPs were significantly associated with the development of high-grade dysplasia or cancer after correcting for multiple comparisons. The model using significant SNPs alone had improved accuracy in predicting high-grade dysplasia in African American women compared to the use of clinical data (area under the receiver operating characteristic curve for genetic and clinical model = 0.9 and 0.747, respectively).

CONCLUSIONS

These preliminary data serve as proof of concept that there may be a genetic predisposition to developing high-grade cervical dysplasia in African American HIV-infected women. Given the small sample size, the results need to be validated in a separate cohort.

Trichomonas vaginalis acidic phospholipase A2: isolation and partial amino acid sequence

Sexually transmitted diseases are a major cause of acute disease worldwide, and trichomoniasis is the most common and curable disease, generating more than 170 million cases annually worldwide. Trichomonas vaginalis is the causal agent of trichomoniasis and has the ability to destroy in vitro cell monolayers of the vaginal mucosa, where the phospholipases A2 (PLA2) have been reported as potential virulence factors. These enzymes have been partially characterized from the subcellular fraction S30 of pathogenic T. vaginalis strains. The main objective of this study was to purify a phospholipase A2 from T. vaginalis, make a partial characterization, obtain a partial amino acid sequence, and determine its enzymatic participation as hemolytic factor causing lysis of erythrocytes. Trichomonas S30, RF30 and UFF30 sub-fractions from GT-15 strain have the capacity to hydrolyze [2-(14)C-PA]-PC at pH 6.0. Proteins from the UFF30 sub-fraction were separated by affinity chromatography into two eluted fractions with detectable PLA A2 activity. The EDTA-eluted fraction was analyzed by HPLC using on-line HPLC-tandem mass spectrometry and two protein peaks were observed at 8.2 and 13 kDa. Peptide sequences were identified from the proteins present in the eluted EDTA UFF30 fraction; bioinformatic analysis using Protein Link Global Server charged with T. vaginalis protein database suggests that eluted peptides correspond a putative ubiquitin protein in the 8.2 kDa fraction and a phospholipase preserved in the 13 kDa fraction. The EDTA-eluted fraction hydrolyzed [2-(14)C-PA]-PC lyses erythrocytes from Sprague-Dawley in a time and dose-dependent manner. The acidic hemolytic activity decreased by 84% with the addition of 100 μM of Rosenthal's inhibitor.

Sphingomyelinase activity of Trichomonas vaginalis extract and subfractions

Trichomoniasis is one of the most common acute sexually transmitted curable diseases, and it is disseminated worldwide generating more than 170 million cases annually. Trichomonas vaginalis is the parasite that causes trichomoniasis and has the ability to destroy cell monolayers of the vaginal mucosa in vitro. Sphingomyelinases (SMase) are enzymes that catalyze the hydrolysis of sphingomyelin into ceramide and phosphorylcholine. Ceramide appears to be a second messenger lipid in programmed apoptosis, cell differentiation, and cell proliferation. Sphingomyelinase is probably a major source of ceramide in cells. Signal transduction mediated by ceramide leads cells to produce cytokine induced apoptosis during several inflammatory responses. SMase are also relevant toxins in several microorganisms. The main objective of this research is to identify SMase activity of T. vaginalis in the total extract (TE), P30, and S30 subfractions from brooked trophozoites. It was found that these fractions of T. vaginalis have SMase activity, which comes principally from P30 subfraction and was mainly type C. Enzymatic activity of SMase increased linearly with time and is pH dependent with two peaks by pH 5.5 and pH 7.5. The addition of manganese to the reaction mixture increased the SMase activity by 1.97.

The villain team-up or how Trichomonas vaginalis and bacterial vaginosis alter innate immunity in concert

Objectives

Complex interactions of vaginal microorganisms with the genital tract epithelium shape mucosal innate immunity, which holds the key to sexual and reproductive health. Bacterial vaginosis (BV), a microbiome-disturbance syndrome prevalent in reproductive-age women, occurs commonly in concert with trichomoniasis, and both are associated with increased risk of adverse reproductive outcomes and viral infections, largely attributable to inflammation. To investigate the causative relationships among inflammation, BV and trichomoniasis, we established a model of human cervicovaginal epithelial cells colonised by vaginal Lactobacillus isolates, dominant in healthy women, and common BV species (Atopobium vaginae, Gardnerella vaginalis and Prevotella bivia).

Methods

Colonised epithelia were infected with Trichomonas vaginalis (TV) or exposed to purified TV virulence factors (membrane lipophosphoglycan (LPG), its ceramide-phosphoinositol-glycan core (CPI-GC) or the endosymbiont Trichomonas vaginalis virus (TVV)), followed by assessment of bacterial colony-forming units, the mucosal anti-inflammatory microbicide secretory leucocyte protease inhibitor (SLPI), and chemokines that drive pro-inflammatory, antigen-presenting and T cells.

Results

TV reduced colonisation by Lactobacillus but not by BV species, which were found inside epithelial cells. TV increased interleukin (IL)-8 and suppressed SLPI, likely via LPG/CPI-GC, and upregulated IL-8 and RANTES, likely via TVV as suggested by use of purified pathogenic determinants. BV species A vaginae and G vaginalis induced IL-8 and RANTES, and also amplified the pro-inflammatory responses to both LPG/CPI-GC and TVV, whereas P bivia suppressed the TV/TVV-induced chemokines.

Conclusions

These molecular host–parasite–endosymbiont–bacteria interactions explain epidemiological associations and suggest a revised paradigm for restoring vaginal immunity and preventing BV/TV-attributable inflammatory sequelae in women.

Antibodies to Trichomonas vaginalis surface glycolipid

BACKGROUND

Human trichomoniasis is the most common non-viral sexually transmitted disease, yet immune responses are not well studied.

METHODS

Since the Trichomonas vaginalis lipophosphoglycan (TvLPG) is an important virulence factor, a bank of eight monoclonal antibodies was generated to define the antigen in clinical isolates. The TvLPG-specific antibody response of women who were culture positive (n=33) or negative (n=33) for T vaginalis infection was determined by isotype-specific ELISA.

RESULTS

The bank of monoclonal antibodies reacted with conserved surface TvLPG epitopes in 27 isolates from pregnant women at their first prenatal visit. Conserved TvLPG epitopes were shown to be surface exposed by immunofluorescence. Sera collected from the same patients at the same time were assayed for specific antibodies. Serum and vaginal secretions from 33 T vaginalis-positive women had statistically higher IgG anti-TvLPG levels than age-matched and race-matched negative controls in the same clinical study (p<0.01). Vaginal IgA anti-TvLPG levels of the women with trichomoniasis were almost significantly higher than controls (p=0.055). Infected women with normal pregnancies had significantly higher vaginal IgG anti-TvLPG values than infected women with adverse outcomes of pregnancy.

CONCLUSIONS

These antibody responses show that infected women can respond to the conserved TvLPG antigen. Since antibodies to trichomonad surface LPG protect in a bovine model of trichomoniasis, the role of these antibodies in the human disease should be investigated.

Trichomonas vaginalis and Tritrichomonas foetus: interaction with fibroblasts and muscle cells - new insights into parasite-mediated host cell cytotoxicity

Trichomonas vaginalis and Tritrichomonas foetus are parasitic, flagellated protists that inhabit the urogenital tract of humans and bovines, respectively. T. vaginalis causes the most prevalent non-viral sexually transmitted disease worldwide and has been associated with an increased risk for human immunodeficiency virus-1 infection in humans. Infections by T. foetus cause significant losses to the beef industry worldwide due to infertility and spontaneous abortion in cows. Several studies have shown a close association between trichomonads and the epithelium of the urogenital tract. However, little is known concerning the interaction of trichomonads with cells from deeper tissues, such as fibroblasts and muscle cells. Published parasite-host cell interaction studies have reported contradictory results regarding the ability of T. foetus and T. vaginalis to interact with and damage cells of different tissues. In this study, parasite-host cell interactions were examined by culturing primary human fibroblasts obtained from abdominal biopsies performed during plastic surgeries with trichomonads. In addition, mouse 3T3 fibroblasts, primary chick embryo myogenic cells and L6 muscle cells were also used as models of target cells. The parasite-host cell cultures were processed for scanning and transmission electron microscopy and were tested for cell viability and cell death. JC-1 staining, which measures mitochondrial membrane potential, was used to determine whether the parasites induced target cell damage. Terminal deoxynucleotidyltransferase-mediated dUTP nick end labelling staining was used as an indicator of chromatin damage. The colorimetric crystal violet assay was performed to ana-lyse the cytotoxicity induced by the parasite. The results showed that T. foetus and T. vaginalis adhered to and were cytotoxic to both fibroblasts and muscle cells, indicating that trichomonas infection of the connective and muscle tissues is likely to occur; such infections could cause serious risks to the infected host.

Analysis of the NTPDase and ecto-5'-nucleotidase profiles in serum-limited Trichomonas vaginalis

Trichomonas vaginalis is a parasite of the human urogenital tract that causes trichomonosis, the most prevalent non-viral sexually transmitted disease. Ectonucleoside triphosphate diphosphohydrolase (NTPDase) family members, which hydrolyse extracellular ATP and ADP and ecto-5'-nucleotidase, which hydrolyses AMP, have been characterised in T. vaginalis. For trichomonad culture, the growth medium is supplemented with 10% serum, which is an important source of nutrients, such as adenosine. Here, we investigated the ATP metabolism of T. vaginalis trophozoites from long-term cultures and clinical isolates under limited bovine serum conditions (1% serum). The specific enzymatic activities were expressed as nmol inorganic phosphate (Pi) released/min/mg protein, the gene expression patterns were determined by reverse transcriptase-polymerase chain reaction, the extracellular adenine nucleotide hydrolysis was analysed by high performance liquid chromatography and the cell cycle analysis was assessed by flow cytometry. Serum limitation led to the profound activation of NTPDase and ecto-5'-nucleotidase activities. Furthermore, the levels of NTPDase A and B transcripts increased and extracellular ATP metabolism was activated, which led to enhanced ATP hydrolysis and the formation of ADP and AMP. Moreover, the cell cycle was arrested at the G0/G1 stage, which suggested adenosine uptake. Our data suggest that under conditions of serum limitation, NTPDase and ecto-5'-nucleotidase play a role in providing the adenosine required for T. vaginalis growth and that this process contributes to the establishment of parasitism.

Trichomonas vaginalis: current understanding of host-parasite interactions

Trichomonas vaginalis is a sexually transmitted obligate extracellular parasite that colonizes the human urogenital tract. Despite being of critical importance to the parasite's survival relatively little is known about the mechanisms employed by T. vaginalis to establish an infection and thrive within its host. Several studies have focused on the interaction of the parasite with host cells and extracellular matrix, identifying multiple suspected T. vaginalis adhesins. However, with the exception of its surface lipophosphoglycan, the evidence supporting a role in adhesion is indirect or controversial for many candidate molecules. The availability of the T. vaginalis genome sequence paved the way for genomic analyses to search for proteins possibly involved in host-parasite interactions. Several proteomic analyses have also provided insight into surface, soluble and secreted proteins that may be involved in Trichomonas pathogenesis. Although the accumulation of molecular data allows for a more rational approach towards identifying drug targets and vaccine candidates for this medically important parasite, a continued effort is required to advance our understanding of its biology. In the present chapter, we review the current status of research aimed at understanding T. vaginalis pathogenesis. Applied experimental approaches, an overview of significant conclusions drawn from this research and future challenges are discussed.

Trichomonas gallinae, in comparison to Tetratrichomonas gallinarum, induces distinctive cytopathogenic effects in tissue cultures

In the present study the interaction of three genetically different clonal cultures of Trichomonas gallinae and Tetratrichomonas gallinarum with a permanent chicken liver (LMH) and a permanent quail fibroblast (QT35) cell culture was studied. Proliferation of T. gallinae cells was associated with a disintegration of the cell monolayer. The initial lesions on the LMH monolayer consisted of a progressive accumulation of the flagellate, forming clumps attached to the monolayer. A prolonged incubation time was characterized by appearance of holes in the cell monolayer with accumulation of trichomonads at their periphery. According to the severeness of the monolayer disruption differences among three tested T. gallinae clones were noticed. Furthermore, filtrates obtained either from axenic cultures of T. gallinae or from infected cell cultures produced a cytopathogenic effect similar to the protozoal cells, on both types of cell cultures. However, the destructive effect of the flagellates and their cell-free filtrates was much more pronounced on the LMH monolayer in comparison with the QT35 cells. Furthermore, freshly seeded LMH and QT35 cells suspended in cell-free filtrates of T. gallinae were unable to form a confluent monolayer. In comparison to T. gallinae, clonal cultures of T. gallinarum or their cell-free filtrates produced no effect on both types of monolayers. Interestingly, the cell-free filtrates obtained from both trichomonad species had an effect on the viability of both cell cultures. However, the cytotoxic effect of T. gallinarum filtrates was less severe than that recorded by T. gallinae. Consequently, for the first time a destruction of specified monolayers induced by T. gallinae-free filtrates could be demonstrated.

Refractory Trichomoniasis in HIV-positive and HIV-negative Subjects

Trichomonas vaginalis, a common pathogen, remains widely unknown to the public. Its clinical consequences include upper genital tract infection, increased risk of preterm delivery, and increased risk of HIV transmission. Diagnostic tests, especially in men, have historically had low sensitivity, but the recent development of rapid, reliable point-of-care testing is a step toward improved detection. Reliable treatments for trichomoniasis are limited to the nitroimidazoles, and options for cases with either hypersensitivity or resistance remain limited. In select resistant cases, alternatives, most notably paromomycin, may play a role. A complex interaction exists between T. vaginalis and HIV, whereby women with trichomoniasis are at increased risk for HIV and vice versa. It is hoped that diagnosis and treatment of trichomoniasis in women at high risk for HIV may help to lower the incidence of both infections.

Chemical structure of Trichomonas vaginalis surface lipoglycan: a role for short galactose (β1-4/3) N-acetylglucosamine repeats in host cell interaction

The extracellular parasite Trichomonas vaginalis contains a surface glycoconjugate that appears to mediate parasite-host cell interaction via binding to human galectin-1. This glycoconjugate also elicits cytokine production from human vaginal epithelial cells, implicating its role in modulation of host immune responses. We have analyzed the structure of this glycoconjugate, previously described to contain the sugars rhamnose (Rha), N-acetylglucosamine (GlcNAc), galactose (Gal), xylose (Xyl), N-acetylgalactosamine (GalNAc), and glucose (Glc), using gas chromatograph mass spectrometry (GC-MS), matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF), electrospray MS/MS, and nuclear magnetic resonance (NMR), combined with chemical and enzymatic digestions. Our data reveal a complex structure, named T. vaginalis lipoglycan (TvLG), that differs markedly from Leishmania lipophosphoglycan and Entamoeba lipopeptidophosphoglycan and is devoid of phosphosaccharide repeats. TvLG is composed of an α1–3 linked polyrhamnose core, where Rha residues are substituted at the 2-position with either β-Xyl or chains of, on average, five N-acetyllactosamine (-3Galβ1–4GlcNAcβ1-) (LacNAc) units and occasionally lacto-N-biose (-3Galβ1-3GlcNAcβ1-) (LNB). These chains are themselves periodically substituted at the Gal residues with Xyl-Rha. These structural analyses led us to test the role of the poly-LacNAc/LNB chains in parasite binding to host cells. We found that reduction of poly-LacNAc/LNB chains decreased the ability of TvLG to compete parasite binding to host cells. In summary, our data provide a new model for the structure of TvLG, composed of a polyrhamnose backbone with branches of Xyl and poly-LacNAc/LNB. Furthermore, the poly-LacNAc side chains are shown to be involved in parasite-host cell interaction.

Sexually transmitted infections and risk of prostate cancer: review of historical and emerging hypotheses

Since the early 1950s when sexually transmitted infections (STIs) were first proposed as a possible risk factor for prostate cancer, numerous epidemiologic studies have been conducted. Initially, these studies were primarily small case-control studies with retrospective, self-reported assessments of a narrow range of STIs, typically either any STIs, or gonorrhea and syphilis. However, as new STIs have been discovered/recognized, new and better tests to detect histories of STIs have been developed, and new resources for prostate cancer research have been created, epidemiologic studies have expanded to include a wide range of STIs, and have moved towards more rigorous, prospective study designs and serological assessment of STI histories. The results of these studies are reviewed and discussed, as well as possible new avenues of research, such as Trichomonas vaginalis infection and infections not typically considered to be sexually transmitted.

Immunohistochemical study of the vaginal inflammatory response in experimental trichomoniasis

In the present paper, the acute and subchronical inflammatory processes of the vaginal epithelial were studied in mice experimentally infected with two Trichomonas vaginalis strains of different pathogenicity, by means of histological and immunological methods. There was an increase in the stratified epithelium layers as well as edema produced by the increase of vascularization in the propia submucosa and infiltration of leukocytes. The proliferation of the vaginal epithelium favors the settlement and persistence of the parasitic infection. All of the findings corresponded with signs of a systemic disease being observed in the animals, including significant weight loss and also intestinal invasion. The entire inflammatory process has been corroborated by studies of adhesion molecules such as E-Selectin, VCAM-1 and PECAM-1. A correlation between the time of appearance and the perseverance of the inflammatory process with E-Selectin and VCAM-1 expression was observed, but not with PECAM-1. The strain with a higher pathogenicity was able to invade deep vaginal tissues and thus, parasites could not be detected by vaginal washings. This may be an important cause of diagnosis and treatment failure. Also, by the different localization of trichomonads, it appeared that the battle between host and parasite took place in different areas dependent upon the characteristics of the strain.

Trichomonas vaginaliskills and eats – evidence for phagocytic activity as a cytopathic effect

This study reports that the cytopathic effect ofTrichomonas vaginalis, an important human parasite of the urogenital tract, occurs due to mechanical stress and subsequent phagocytosis of the necrotic cells. The investigation was done using a primary culture of bovine oviduct epithelial cells (BOECs), grown either in monolayers or as floating cells. Trophozoites displaying different virulence levels were co-incubated with BOECs for times varying between 1 min and 48 h. Analyses were performed using videomicroscopy, scanning and transmission electron microscopy, colourimetric assays and cytochemistry. Injury was observed as early as 1 h after incubation, while after 12 h the host cells were severely damaged when a fresh trichomonad isolate was used. Trichomonads attack the host cells by clustering around them. Mechanical stress on the microvilli of the host cells was observed and appeared to induce plasma membrane damage and cell death. After membrane injury and lysis, fragments of the necrotic cells were ingested by trichomonads. Phagocytosis occurred by trichomonads avidly eating large portions of epithelial cells containing the nucleus and other organelles, but living or intact cells were not ingested. Necrotic fragments were rapidly digested in lysosomes, as shown by acid phosphatase and ruthenium red assays where only the BOECs were labelled. The lytic capacity of the trichomonads was more pronounced in host cell suspensions.

Trichomonosis and subsequent risk of prostate cancer in the Prostate Cancer Prevention Trial

We previously observed a positive association between a history of trichomonosis, a sexually transmitted infection caused by the protozoan, Trichomonas vaginalis, and prostate cancer risk in the Health Professionals Follow-up Study. To determine the reproducibility of this finding, we conducted a second, prospective investigation of trichomonosis and prostate cancer in the Prostate Cancer Prevention Trial. Participants were men (>or=55 years of age) with no evidence of prostate cancer at enrollment (n = 18,882). Men were screened annually for prostate cancer, and if not diagnosed during the trial, were offered an end-of-study prostate biopsy. Cases were a sample of men diagnosed with prostate cancer on any biopsy after visit 2 or on their end-of-study biopsy (n = 616). Controls were men not diagnosed with prostate cancer during the trial or on their end-of-study biopsy (n = 616). Controls were frequency-matched to cases by age, treatment arm, and family history of prostate cancer. Serum from visit 2 was tested for anti-T. vaginalis IgG antibodies. No association was observed between T. vaginalis serostatus and prostate cancer. 21.5% of cases and 24.8% of controls had low seropositivity, and 15.2% and 15.0% had high seropositivity. Compared to seronegative men, the odds ratio of prostate cancer for men with low seropositivity was 0.83 [95% confidence interval (CI): 0.63-1.09), and that for men with high seropositivity was 0.97 (95% CI: 0.70-1.34). Given the original strong biologic rationale and potential for prevention, additional studies are warranted to help resolve discrepancies between study findings and to further investigate this hypothesis from a variety of different approaches.

Structural details and composition of Trichomonas vaginalis lipophosphoglycan in relevance to the epithelial immune function

Trichomonas vaginalis causes the most common non-viral sexually transmitted infection linked to increased risk of premature birth, cervical cancer and HIV. This study defines molecular domains of the parasite surface glycoconjugate lipophosphoglycan (LPG) with distinct functions in the host immunoinflammatory response. The ceramide phospho-inositol glycan core (CPI-GC) released by mild acid had Mr of approximately 8,700 Da determined by MALDI-TOF MS. Rha, GlcN, Gal and Xyl and small amounts of GalN and Glc were found in CPI-GC. N-acetyllactosamine repeats were identified by endo-beta-galactosidase treatment followed by MALDI-MS and MS/MS and capLC/ESI-MS/MS analyses. Mild acid hydrolysis led to products rich in internal deoxyhexose residues. The CPI-GC induced chemokine production, NF-kappaB and extracellular signal-regulated kinase (ERK)1/2 activation in human cervicovaginal epithelial cells, but neither the released saccharide components nor the lipid-devoid LPG showed these activities. These results suggest a dominant role for CPI-GC in the pathogenic epithelial response to trichomoniasis.

Global epidemiology and control of Trichomonas vaginalis

PURPOSE OF REVIEW

Trichomonas vaginalis is the most common curable sexually transmitted infection. Despite a number of serious health consequences including facilitation of HIV transmission, pelvic inflammatory disease and adverse outcomes of pregnancy it remains an under-recognized condition. This review aims to update the reader on the global epidemiology and control of T. vaginalis.

RECENT FINDINGS

The burden of T. vaginalis infection is found in resource-limited settings and high-risk groups in industrialized settings. Utilization of polymerase chain reaction-based diagnostics has enhanced our understanding of the epidemiology of T. vaginalis both at the population level and in sexual partners. High rates of asymptomatic infection in male partners of infected females and subsequent re-infection have significant implications for control programmes. Further studies investigating the role of T. vaginalis in facilitating HIV transmission has highlighted its significance and the need to develop and implement control interventions.

SUMMARY

Future research to develop cheap, point-of-care diagnostic tests will allow a greater understanding of T. vaginalis epidemiology. In addition, the effect of treatment on outcome of pregnancy and HIV acquisition requires further study. This will in turn facilitate operational studies evaluating optimal control strategies and their impact on the complications of T. vaginalis.

Differential soluble protein expression between Trichomonas vaginalis isolates exhibiting low and high virulence phenotypes

A comparative analysis of proteomic maps of long-term grown and fresh clinical Trichomonas vaginalis isolates exhibiting low and high virulence phenotypes, respectively, was performed using two-dimensional gel electrophoresis and mass spectrometry. Of 29 protein spots differentially expressed between the isolates, 19 were over-expressed in the isolate exhibiting high virulence phenotype: proteins associated with cytoskeletal dynamics, such as coronin and several isoforms of actin, as well as proteins involved in signal transduction, protein turnover, proteolysis, and energetic and polyamine metabolisms were identified. Some malate dehydrogenase, fructose-1,6-bisphosphate aldolase and ornithine cyclodeamidase isoforms were exclusively expressed by the highly virulent isolate. During interaction assays with VEC, parasites exhibiting high virulence phenotype rapidly adhered and switched to amoeboid forms. In contrast, low adhesion and no morphological transformation were observed in parasites displaying low virulence phenotype. Our findings demonstrate that expression of specific proteins by high and low virulence parasites could be associated with the ability of each isolate to undergo morphological transformation and interact with host cells. Such data represent an important step towards understanding of the complex interaction network of proteins that participate in the mechanism of pathogenesis of this protozoan.

Entry and intracellular location of Mycoplasma hominis in Trichomonas vaginalis

The parasite Trichomonas vaginalis causes one of the most common non-viral sexually transmitted infections in humans. The coexistence of different sexually transmitted diseases in the same individual is very common, such as vaginal infections by T. vaginalis in association with Mycoplasma fermentans or Mycoplasma hominis. However, the consequences and behavior of mycoplasma during trichomonad infections are virtually unknown. This study was undertaken to elucidate whether mycoplasmas enter and leave trichomonad cells and if so how. M. hominis was analyzed in different trichomonad isolates and the process of internalization and the pathway within the parasite was studied. Parasites naturally and experimentally infected with mycoplasmas were used and transmission electron microscopy, cytochemistry and PCR analyses were performed. The results show that: (1) M. hominis enters T. vaginalis cells by endocytosis; (2) some mycoplasmas use a terminal polar tip as anchor to the trichomonad plasma membrane; (3) some trichomonad isolates are able to digest mycoplasmas, mainly when the trichomonads are experimentally infected; (4) some fresh virulent isolates are able to maintain mycoplasmas as cohabitants in the cell's interior; (5) some mycoplasmas are able to escape from the vacuole to the trichomonad cytosol, and trichomonad plasma membrane budding suggested that mycoplasmas could leave the parasite cell.

Systemic immune response to Trichomonas vaginalis infection during pregnancy

OBJECTIVE

The objective of this study was to characterize the systemic immune response in women with trichomoniasis in pregnancy as compared with uninfected women.

STUDY DESIGN

A nested case control study was performed on 195 serum samples. Serum concentrations of cytokines, chemokines, and C-reactive protein (CRP) were compared between infected and uninfected women. Cytokines and chemokines were measured using a multiplex bead assay. The CRP concentrations were determined using a standard enzyme-linked immunosorbent assay method.

RESULTS

The median serum concentration of granulocyte-macrophage colony-stimulating factor (GM-CSF) was significantly higher in the trichomonas-infected group compared with the uninfected group (8.9 pg/mL vs. 5.7 pg/mL; P <0.001). The mean log-transformed CRP values were higher in the infected group compared with the uninfected group (1.66 vs. 1.27; P = 0.03).

CONCLUSIONS

The results of this study suggest that trichomoniasis during pregnancy can lead to a systemic immune response in some women as exhibited by elevation in the serum concentrations of both GM-CSF and CRP.

Nitric oxide production and nitric oxide synthase immunoreactivity in Naegleria fowleri

Free-living ameba Naegleria fowleri produces an acute and fatal infectious disease called primary amebic meningoencephalitis (PAM), whose pathophysiological mechanism is largely unknown. The aim of this study was to investigate the role of nitric oxide (NO) in PAM. Although NO has a cytotoxic effect on various parasites, it is produced by others as part of the pathology, as is the case with Entamoeba histolytica. To test for the production of NO, we analyzed whether antibodies against mammalian NO synthase isoforms (neuronal, inducible, and endothelial) presented immunoreactivity to N. fowleri proteins. We found that the trophozoites produced NO in vitro. The Western blot results, which showed N. fowleri trophozoites, contained proteins that share epitopes with the three described mammalian NOS, but have relative molecular weights different than those described in the literature, suggesting that N. fowleri may contain undescribed NOS isoforms. Moreover, we found that trophozoites reacted to the NOS2 antibody, in amebic cultures as well as in the mouse brain infected with N. fowleri, suggesting that nitric oxide may participate in the pathogenesis of PAM. Further research aimed at determining whether N. fowleri contains active novel NOS isoforms could lead to the design of new therapies against this parasite.

Iron modulates ecto-phosphohydrolase activities in pathogenic trichomonads

The presence of iron in the extracellular medium is essential for both in vivo and in vitro survival of pathogenic microorganisms, including Trichomonas vaginalis and Tritrichomonas foetus. In these parasites, iron is directly involved in the proliferation, protein expression and activation of critical enzymes. The purpose of this study was to investigate the role of iron in ecto-ATPase, ecto-phophatase and secreted phosphatase activities of these trichomonads. We observed that trichomonads grown in iron-depleted medium exhibited a remarkable decrease in both ecto-ATPase and ecto-phosphatase activities, when compared to those cultivated under control conditions (iron-rich medium). Furthermore, parasites grown in iron-depleted medium restored their enzyme activities when they were re-inoculated into fresh iron-rich medium. We demonstrated that modulation of ecto-phosphohydrolase activities is due neither to enzyme-iron nor to substrate-iron complex formation, since iron addition directly to the medium where the enzymatic reactions occurred did not alter their activities. Previously, we had reported that a fresh clinical isolate of T. vaginalis was much more cytotoxic to epithelial cell monolayers than a long-term cultured one. In this study we witnessed that the fresh isolate of T. vaginalis presented higher activities to all herein investigated enzymes than the long-term cultured one. Altogether, our data clearly point out that iron has a pivotal role in the expression of phosphohydrolases in both trichomonads.