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PubMed1988

Identification and properties of Trichomonas vaginalis proteins involved in cytadherence.

Trichomonas vaginalis NYH286 surface proteins which are candidates for mediating parasite cytadherence (adhesins) were identified. At least four trichomonad protein ligands ranging in relative molecular mass from 65 to less than or equal to 21 kilodaltons were found to selectively bind to chemically stabilized HeLa cells. The proteins were present on the surfaces of 10 different isolates of T. vaginalis examined; however, the nonpathogenic trichomonad T. tenax did not possess similar HeLa cell-binding proteins under identical experimental conditions, suggesting that these proteins are unique to the pathogenic human trichomonads. The surface nature of the candidate adhesins was confirmed by the ability of the proteins on intact, live organisms to be radioiodinated and to be removed with trypsin treatment. Rabbit antiserum (immunoglobulin G fraction) generated against adhesin proteins electroeluted from acrylamide preparations inhibited cytadherence compared with control immunoglobulin G. An adherence-negative subpopulation of T. vaginalis NYH286 organisms was also isolated. These nonadherent trichomonads did not synthesize the adhesin proteins. Interestingly, absence of adhesins from these parasites paralleled expression of a major immunogen known to undergo phenotypic variation. Revertant organisms derived from the adherence-minus subpopulation synthesized the adhesins and attached to HeLa cells. The emergence of revertant adherent T. vaginalis organisms also corresponded with the appearance of parasites which were without the major immunogen on their surface. Finally, it was determined that only those parasites lacking the major surface immunogen were capable of adherence and toxicity to HeLa cells.

Animals↗
PubMed1989

Trichomonas vaginalis surface proteinase activity is necessary for parasite adherence to epithelial cells.

The role of cysteine proteinases in adherence of Trichomonas vaginalis NYH 286 to HeLa and human vaginal epithelial cells was evaluated. Only pretreatment of trichomonads, but not epithelial cells, with N-alpha-p-tosyl-L-lysine chloromethyl ketone (TLCK), an inhibitor of trichomonad cysteine proteinases, greatly diminished the ability of T. vaginalis to recognize and bind to epithelial cells. Leupeptin and L-1-tosylamide-2-phenylethyl chloromethyl ketone, other cysteine proteinase inhibitors, also decreased T. vaginalis cytadherence. Parasites incubated with TLCK and washed extensively still did not adhere to cells at levels equal to those seen for control trichomonads treated with phosphate-buffered saline or culture medium alone. Exposure of TLCK-treated organisms with other cysteine proteinases restored cytadherence levels, indicating that proteinase action on the parasite surface is prerequisite for host cell attachment. Concentrations of TLCK which inhibited cytadherence did not alter the metabolism of T. vaginalis, as determined by metabolic labeling of trichomonad proteins; the protein patterns of T. vaginalis in the presence and absence of TLCK were identical. Kinetics of TLCK-mediated inhibition of cytadherence of other T. vaginalis isolates with different levels of epithelial-cell parasitism were similar to the concentration-dependent inhibition seen for isolate NYH 286. Incubation of TLCK-treated, washed organisms in growth medium resulted in regeneration of adherence. Finally, treatment of T. vaginalis organisms with proteinase inhibitors for abrogation of cytadherence effectively rendered the trichomonads unable to kill host cells, which is consistent with the contact-dependent nature of host cytotoxicity. These data show for the first time the involvement of T. vaginalis cysteine proteinases in parasite attachment to human epithelial cells. These results have implications for future pharmacologic intervention at a key step in infection.

Adhesiveness↗
PubMed1989

Relatedness of structures of a major immunogen in Trichomonas vaginalis isolates.

Solubilization of live Trichomonas vaginalis organisms with detergent caused the release of cysteine proteinases in the detergent extract which were inhibitable with N-alpha-p-tosyl-L-lysine chloromethyl ketone. The detergent extracts of all isolates tested possessed similar cysteine proteinase activities. These parasite proteinases rapidly degraded a prominent immunogen whose surface disposition undergoes phenotypic variation in some isolates. The relatedness of the forms of this immunogen among all isolates tested was confirmed by identical immunoblot patterns of autolysed immunogen, and data suggest the presence of repeating units or at least equidistant sites for proteinase cleavage within the immunogen molecule.

Animals↗
PubMed1990

Analysis of the proteinases of representative Trichomonas vaginalis isolates.

Isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with acrylamide copolymerized with gelatin (substrate-SDS-PAGE) were combined to evaluate the proteinases of both long-term-grown and fresh isolates of Trichomonas vaginalis. This two-dimensional substrate-SDS-PAGE resolved as many as 23 distinct proteinase activities in several isolates, and proteinases had relative molecular masses between 23 and 110 kilodaltons (kDa). Isoelectric points (pI) of proteinases ranged from 5.7 to 7.0. Overall, the various representative proteinase profiles were similar among those of long-term-grown and fresh isolates, although heterogeneity existed among several cysteine proteinase activities. Pattern changes were detected in fresh isolates passaged over several weeks, showing the ability of proteinases to be differentially expressed and to undergo phase variation. The two-dimensional proteinase patterns were very reproducible for isolates analyzed over a certain period of time before expression of some proteinases varied. The heterogeneity and differential expression of certain proteinases were not coordinated with phenotypic variation of already characterized immunogens and adhesins. Data suggesting that a 43-kDa proteinase resided on the parasite surface were obtained on the basis of removal of activity following pronase or proteinase K treatment of live organisms. Finally, immunized experimental animals produced antibody to many T. vaginalis proteinases, which indicates the immunogenic nature of trichomonad proteinases.

Animals↗
PubMed1991

The phenotypically variable surface protein of Trichomonas vaginalis has a single, tandemly repeated immunodominant epitope.

Trichomonas vaginalis is a sexually transmitted protozoan parasite that undergoes phenotypic variation for numerous surface proteins. A monoclonal antibody (MAb) was used to isolate an approximately 400-bp cDNA encoding a fragment of an important phenotypically varying immunogen of T. vaginalis (Mr = 270 kDa; P270). The MAb completely inhibited the binding of P270 by antibody in sera of patients and by antibody in monospecific antiserum obtained toward purified P270, indicating that P270 contained only one immunodominant epitope. Hydrophilicity plot analysis of the deduced amino acid sequence of the recombinant protein predicted the hexapeptide sequence DREGRD as the antigenic determinant of P270. Synthetic peptides synthesized to this region demonstrated that the amino acid sequence DREGRD is important for antibody binding. Seven adjacent amino acids also contributed substantially to maximal recognition of the epitope by the MAb. A single transcript of approximately 9.5 kb, a size compatible with the reported Mr of the immunogen, hybridized to the cDNA in Northern blots of total RNA from T. vaginalis. DNA sequence and Southern blot analysis determined the epitope to be encoded by a 339-bp unit, which was found to be tandemly repeated at least 12 times within the single-copy gene. This 12-mer unit would only constitute approximately 50% of the protein, yet it is responsible for all of the serum antibody to the immunogen produced by animals and humans. The epitope sequence was found in all fresh and long-term-grown organisms examined to date, demonstrating the stability and conservation of this gene.

Amino Acid Sequence↗
PubMed1992

A novel neutrophil-activating factor released by Trichomonas vaginalis.

We have investigated the effects of a novel neutrophil-activating factor released by Trichomonas vaginalis (TV-NAF) on neutrophil chemotaxis. TV-NAF was present in the supernatant from 10(7) T. vaginalis (STV) cultured in 1 ml of serum-free Hanks' balanced salt solution (HBSS) at 37 degrees C for 30 min. With a multichamber chemotactic assay, we found that there were 112 +/- 15 migrated neutrophils (mean +/- standard deviation, n = 7) for STV and 11 +/- 4 for HBSS per high-power field (x 400). STV was also able to induce neutrophil actin assembly (increased 1.5-fold), enhance expression of complement receptor type 3 (increased 5-fold), and promote intracellular calcium mobilization (increased 2.5-fold). There was no chemotactic activity in the preparation of STV from killed trichomonads. The fact that heating up to 100 degrees C or deproteinization by treatment with proteinase K at 65 degrees C for 1 h did not abolish its chemotactic activity suggests that the TV-NAF involved was not a protein. The chemotactic activity of TV-NAF was associated with the fraction containing small molecules of less than 3,000 Da. Therefore, the possibility that eicosanoid production by trichomonads is responsible for neutrophil activation was investigated. Leukotriene B4 (LTB4; 500 pg/ml) but not thromboxane B2 (< 20 pg/ml) or prostaglandin E2 (< 8 pg/ml) was found in the STV by radioimmunoassay. Production of LTB4 by trichomonads was time dependent and increased twofold when arachidonic acid (100 microM) was added but was not decreased when eicosanoid inhibitors were present. Evidence for the presence of LTB4 in STV was further provided by the fact that rabbit anti-LTB4 antiserum could abolish the chemotactic activity of STV. These studies suggest that the spontaneous release of TV-NAF, which is most likely LTB4, may activate neutrophils, presumably through a different arachidonate metabolic pathway than that in mammalian cells.

Actins↗
PubMed1992

Mouse intravaginal infection with Trichomonas vaginalis and role of Lactobacillus acidophilus in sustaining infection.

Recent work with a mouse model of Trichomonas vaginalis infection indicated that only 25% of mice harbor Lactobacillus spp. and that T. vaginalis infection rates fall rapidly after 7 days postinfection. In women infected with T. vaginalis, there is a disruption of the Lactobacillus population, which usually predominates. In an attempt to establish a better mouse intravaginal infection that resembles human disease, we established Lactobacillus acidophilus in estrogenized BALB/c mice. T. vaginalis was then inoculated intravaginally into mice previously infected with L. acidophilus and into mice in an untreated group. From 52 mice, 50-microliters vaginal washes were collected, cultured, and examined daily for live trichomonads after inoculation. Although initial infectivity in the two groups was comparable (79 to 83%), L. acidophilus-infected mice showed greater duration of infection. At day 24 postinfection, 69% of L. acidophilus-infected mice were still infected with T. vaginalis compared with only 11% of untreated mice (P = 0.002). The addition of L. acidophilus did not significantly alter the resident mouse vaginal flora. By the addition of L. acidophilus, the mouse will be valuable for studying factors involved in T. vaginalis infectivity and pathogenicity.

Animals↗
PubMed1995

Analysis of human immunoglobulin-degrading cysteine proteinases of Trichomonas vaginalis.

Trichomonas vaginalis is a protozoan parasite that causes a widely distributed sexually transmitted disease (STD). Since immunoglobulin G (IgG) antibodies to specific trichomonad immunogens are found in serum and vaginal washes (VWs) from patients with trichomoniasis, a potential mechanism of immune evasion by this parasite might be the ability of T. vaginalis proteinases to degrade human immunoglobulins (Igs). Incubation of human IgG with lysates of T. vaginalis organisms resulted in time- and concentration-dependent degradation of the heavy chain. Secretory IgA was degraded similarly. Inhibitors of cysteine proteinases, when added to trichomonal lysates, abolished IgG and IgA degradation, while EDTA, a metalloproteinase inhibitor, did not. Substrate-gel electrophoresis with human IgG, IgM, or IgA copolymerized with acrylamide revealed several distinct cysteine proteinases in both lysates and culture supernatants from logarithmically growing parasites that degraded all classes of human antibodies. Trichomonal lysates and supernatants of numerous isolates tested all had Ig-degrading activity. Finally, proteolytic activity against IgG was detected in most (26 of 33; 78%) VWs from patients with trichomoniasis. In contrast, 18 of 28 (65%) VWs from women without trichomoniasis or from patients infected with other STDs had no detectable proteinases when tested in an identical manner. The other 10 of these 28 VWs (35%) had smaller amounts of detectable Ig-degrading proteinases. These differences in Ig-degrading proteinase activity between patients with and without trichomoniasis, regardless of coinfecting STDs, were statistically significant (P = 0.001). These results illustrate that T. vaginalis is capable of degrading human Igs.

Animals↗
PubMed1996

Inducible immunity to Trichomonas vaginalis in a mouse model of vaginal infection.

We studied the protective effect of subcutaneous immunization with Trichomonas vaginalis in a mouse model of vaginal infection. BALB/c mice were immunized with various doses of T. vaginalis (4.5 x 10(5), 9 x 10(6), and 1 x 10(8) organisms per ml) suspended in Freund's complete adjuvant 56 days prior to vaginal infection and were given booster injections of the same doses of T. vaginalis in Freund's incomplete adjuvant 4 weeks later. Control mice were immunized and given booster injections of phosphate-buffered saline suspended in Freund's complete and incomplete adjuvants. The mice were tail bled and vaginal washes were performed at weekly intervals for 4 weeks to determine the isolation of T. vaginalis and the serum and vaginal antibody reactivity. Mice which had been immunized and given booster immunizations had significantly fewer intravaginal infections and had increased serum and vaginal antibody responses compared with those of control mice (P < 0.01). Mice that were vaginally infected, treated with metronidazole, and then reinfected vaginally did not develop protective immunity. Subcutaneous immunization with whole T. vaginalis organisms appears to confer protection against intravaginal challenge with T. vaginalis, protection which is not achieved as a result of prior vaginal infection.

Animals↗
PubMed1998

Cloning and molecular characterization of a cDNA clone coding for Trichomonas vaginalis alpha-actinin and intracellular localization of the protein.

We have identified and sequenced a cDNA clone coding for Trichomonas vaginalis alpha-actinin. Analysis of the obtained sequence revealed that the 2,857-nucleotide-long cDNA contained an open reading frame encoding 849 amino acids which showed consistent homology with alpha-actinins of different species. Such homology was particularly significant in regions which have been reported to represent the actin-binding and Ca2+-binding domains in other alpha-actinins. The deduced protein was also characterized by the presence of a divergent central region thought to play a role in its high immunogenicity. A study of protein localization performed by immunofluorescence revealed that the protein is diffusely distributed throughout the T. vaginalis cytoplasm when the cell is pear shaped. When parasites adhere and transform into the amoeboid morphology, the protein is located only in areas close to the cytoplasmic membrane and colocalizes with actin. Concomitantly with transformation into the amoeboid morphology, alpha-actinin mRNA expression is upregulated.

Actinin↗
PubMed1999

Iron modulates phenotypic variation and phosphorylation of P270 in double-stranded RNA virus-infected Trichomonas vaginalis.

Trichomonas vaginalis infected with a double-stranded RNA virus undergoes phenotypic variation on the basis of surface versus cytoplasmic expression of the immunogenic protein P270. Examination of batch cultures by flow cytofluorometry with monoclonal antibody (MAb) to P270 yields both fluorescent and nonfluorescent trichomonads. Greater numbers and intensity of fluorescent organisms with surface P270 reactive with MAb were evident in parasites grown in medium depleted of iron. Placement of iron-limited organisms in medium supplemented with iron gave increased numbers of nonfluorescent trichomonads. Purified subpopulations of trichomonads with and without surface P270 obtained by fluorescence-activated cell sorting reverted to nonfluorescent and fluorescent phenotypes when placed in high- and low-iron media, respectively. No similar regulation by iron of P270 was evident among virus-negative T. vaginalis isolates or virus-negative progeny trichomonads derived from virus-infected isolates. Equal amounts of P270 were detectable by MAb on immunoblots of total proteins from identical numbers of parasites grown in low- and high-iron media. Finally, P270 was found to be highly phosphorylated in high-iron parasites. Iron, therefore, plays a role in modulating surface localization of P270 in virus-harboring parasites.

Animals↗
PubMed2000

Host and tissue specificity of Trichomonas vaginalis is not mediated by its known adhesion proteins.

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.

Animals↗
PubMed2005

Long-term survival and intracellular replication of Mycoplasma hominis in Trichomonas vaginalis cells: potential role of the protozoon in transmitting bacterial infection.

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.

Animals↗
PubMed2005

Trichomonas vaginalis polyamine metabolism is linked to host cell adherence and cytotoxicity.

Trichomonas vaginalis secretes putrescine that is readily detected in vaginal secretions. We wanted to examine the effect of decreased putrescine synthesis by inhibition of ornithine decarboxylase (ODC) on T. vaginalis. One reason is because inhibition of Tritrichomonas foetus ODC results in growth arrest, destruction of hydrogenosomes, and decreased amounts of hydrogenosomal enzymes. Treatment of T. vaginalis T016 with >/=20 mM 1,4-diamino-2-butanone (DAB) to inhibit ODC resulted in growth arrest, which was reversed by addition of exogenous putrescine. No similar reversal of growth arrest was achieved with the polyamines spermine or spermidine or with iron. Electron microscopic examination of control versus DAB-treated trichomonads did not reveal any adverse effects on the number and integrity of hydrogenosomes. Further, the adhesins AP65, AP51, and AP33 mediating binding to immortalized vaginal epithelial cells (VECs) share identity to enzymes of the hydrogenosome organelle, and there was no difference in amounts of adhesins between control versus DAB-treated T. vaginalis parasites. Likewise, similar patterns and extent of fluorescence were evident for the prominent AP65 adhesin. Surprisingly, DAB treatment increased by 4- to 20-fold above untreated trichomonads handled identically the level of adherence mediated by adhesins. Interestingly, the enhanced attachment to VECs was reversed by exogenous putrescine added to DAB-treated trichomonads. Equally noteworthy was that DAB-treated T. vaginalis with enhanced adherence did not possess the previously reported ability to kill host cells in a contact-dependent fashion mediated by cysteine proteinases, and total cysteine proteinase activity patterns were identical between control and DAB-treated trichomonads. Overall, these data suggest that polyamine metabolism and secreted putrescine are linked to host cell adherence and cytotoxicity.

Animals↗
PubMed2005

Trichomonas vaginalis-induced epithelial monolayer disruption and human immunodeficiency virus type 1 (HIV-1) replication: implications for the sexual transmission of HIV-1.

The objective of this study was to evaluate potential mechanisms of Trichomonas vaginalis involvement in human immunodeficiency virus type 1 (HIV-1) transmission. Polarized monolayer integrity of primary cervical and prostate epithelial cells or cell lines cultured with T. vaginalis was measured by monitoring transepithelium resistance. The effect of T. vaginalis isolates on HIV-1 passage through polarized epithelial cell monolayers was evaluated for HIV-1 p24gag in the basolateral supernatants. Coincubation with T. vaginalis isolates induced disruption of monolayer integrity and resulted in passage of virus to the basolateral side of the monolayer. Furthermore, there was isolate variability in which two isolates induced greater monolayer damage and increased HIV-1 passage than did the other two isolates. Coincubation of T. vaginalis isolates with acutely HIV-1-infected peripheral blood mononuclear cells enhanced HIV-1 replication. This enhancement was associated with cellular proliferation and activation, as well as with tumor necrosis factor alpha production. In contrast to the monolayer disruption, the effect of T. vaginalis on HIV-1 replication was not isolate dependent. Thus, two mechanisms have been identified that could contribute to the epidemiologic association of trichomoniasis with the sexual transmission of HIV-1. (i) T. vaginalis disruption of urogenital epithelial monolayers could facilitate passage of HIV-1 to underlying layers. (ii) Activation of local immune cells by T. vaginalis in the presence of infectious HIV-1 might lead to increased viral replication. Collectively, these data suggest the need for more vigilant efforts in the diagnosis and treatment of T. vaginalis in women and men, especially in countries with a high prevalence of HIV-1.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Beta-succinyl-coenzyme A synthetase from Trichomonas vaginalis is a soluble hydrogenosomal protein with an amino-terminal sequence that resembles mitochondrial presequences.

We describe studies directed toward understanding the biogenesis and origin of the hydrogenosome, an unusual organelle found exclusively in certain anaerobic eukaryotes that lack mitochondria. Hydrogenosomes are involved in fermentative carbohydrate metabolism and are proposed to have arisen through conversion of mitochondria or via endosymbiosis with an anaerobic bacterium. We cloned a gene encoding the beta subunit of the hydrogenosomal protein succinyl-coenzyme A synthetase (beta-SCS) and isolated the protein from Trichomonas vaginalis. The T. vaginalis beta-SCS gene encodes a protein with a calculated molecular mass of 43,980 Da that has 43% amino acid identity (65% similarity) with beta-SCS from Escherichia coli. The trichomonad protein partitions into the soluble fraction of hydrogenosomes treated with sodium carbonate at high pH, consistent with a matrix localization within the organelle. The protein is encoded by a multigene family composed of at least three members. Amino-terminal sequencing of beta-SCS purified from T. vaginalis hydrogenosomes shows that the mature protein lacks the first nine amino acids encoded in the gene. This apparent amino-terminal leader sequence is strikingly similar to that of another hydrogenosomal protein and to mitochondrial presequences.

Amino Acid Sequence↗
PubMed1983

Viability of Trichomonas vaginalis in vitro at four temperatures.

The effect of temperature as a possible factor on the survival of Trichomonas vaginalis for shipment or routine laboratory maintenance was studied. Ten strains of T. vaginalis, ATCC 30001, ATCC 30238, and eight clinical isolates, were examined for viability when kept incubated at 37 degrees C or removed from this temperature and held at 42, 22, or 5 degrees C for increasing lengths of time without subculture or reincubation at 37 degrees C. The order in which the strains remained viable without subculture was: 5 degrees C, 8 to 10 days; 22 degrees C, 4 to 8 days; 37 degrees C, 4 to 6 days; 42 degrees C, less than 2 days. Vials of medium with cells were also held at 22 and 5 degrees C and then reincubated at 37 degrees C. Cultures held at 22 degrees C remained viable 6 to 8 days, whereas those stored at 5 degrees C remained viable 10 to 14 days. These data show that T. vaginalis withstands a wide range of temperatures, particularly below normal growth temperatures without subcultures, beyond what would be expected in mailing cultures.

Female↗