There is a need for a point-of-care serodiagnostic test for women and men for sexually transmitted infections (STIs) caused by Trichomonas vaginalis. Sera from women with this STI and sera from men that were analyzed in studies showing a relationship between serostatus and prostate cancer are highly seropositive in response to trichomonad ␣-actinin and its truncated protein (ACT-P2) (positive control sera). Epitope mapping experiments showed that positive control sera from women had antibodies to 13 distinct epitopes, 5 of which were detected by positive control sera from men. Sera from women and men that were unreactive with ␣-actinin (negative control sera) failed to detect any of the epitopes or other ␣-actinin amino acid sequences. The T. vaginalis ␣-actinin amino acid sequence and the sequences of the epitopes showed little or no identity with those of other proteins of microbial pathogens or the human ␣-actinin 1 (HuACTN1) homolog. Immunoassays such as dot blot, immunoblot, and enzyme-linked immunosorbent assays were used. Positive control sera did not detect HuACTN1 in immunoassays, and the range of levels of identity of ␣-actinin epitopes with HuACTN1 was 0% to 50%. Comparison of the T. vaginalis ␣-actinin epitopes with proteins in data banks, such as Tritrichomonas suis, Candida albicans, and Saccharomyces cerevisiae proteins, gave a range of identity levels of 0% to 22%. Specific 15-mer peptide epitopes of ␣-actinin with low to no identity with other proteins were synthesized and were reactive with positive control sera only. These findings identify epitopes of ␣-actinin as candidate serodiagnostic targets and suggest strongly that a highly seropositive reaction to ␣-actinin suggests exposure to T. vaginalis.T richomonas vaginalis is the most common nonviral causative agent for sexually transmitted infections (STIs). The adverse consequences for the health of women have been well documented (1, 2). Although in the literature it is routinely reported that men infected by their partners resolve their infections, there is neither experimental evidence nor clinical studies proving this. Reports have shown the expression of numerous virulence factors that permit this ancient protist to survive in the changing host environment of the female urogenital region (3-18). Iron is an important modulator of upregulation and downregulation of the expression of virulence genes (8,(19)(20)(21)(22)(23)(24)(25). Key steps for host colonization result from overcoming the urogenital mucous layer (18) in preparation for specific cytoadherence to vaginal epithelial cells (7,9,11,22,24). The intimacy of the host-parasite relationship during colonization and infection is exceedingly complex, as evidenced by the large number of proteinases (4,11,15,26) and the secretion by trichomonads of large amounts of putrescine for spermine uptake and back-conversion to spermidine (13,26). This coating of T. vaginalis by polyamines and host macromolecules affects levels of cytoadherence and cytotoxicity (3, 13).More recently, epidemiologic...

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There is a need for a rapid, accurate serodiagnostic test useful for both women and men infected by Trichomonas vaginalis, which causes the number one sexually transmitted infection (STI). Women and men exposed to T. vaginalis make serum antibody to fructose-1,6-bisphosphate aldolase (ALD), α-enolase (ENO), and glyceraldehyde-3-phosphate dehydrogenase (GAP). We identified, by epitope mapping, the common and distinct epitopes of each protein detected by the sera of women patients with trichomonosis and by the sera of men highly seropositive to the immunogenic protein α-actinin (positive control sera). We analyzed the amino acid sequences to determine the extent of identity of the epitopes of each protein with other proteins in the databanks. This approach identified epitopes unique to T. vaginalis, indicating these peptide-epitopes as possible targets for a serodiagnostic test. Individual or combinations of 15-mer peptide epitopes with low to no identity with other proteins were reactive with positive control sera from both women and men but were unreactive with negative control sera. These analyses permitted the synthesis of a recombinant His6 fusion protein of 111 amino acids with an Mr of ~13.4 kDa, which consisted of 15-mer peptides of two distinct epitopes each for ALD, ENO, and GAP. This recombinant protein was purified by affinity chromatography. This composite protein was detected by enzyme-linked immunosorbent assay (ELISA), dot blots, and immunoblots, using positive control sera from women and men. These data indicate that it is possible to identify epitopes and that either singly, in combination, or as a composite protein represent targets for a point-of-care serodiagnostic test for T. vaginalis.

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Purpose Previous epidemiologic studies have observed positive associations between Trichomonas vaginalis (Tv) serostatus and both prostate cancer (PCa) risk and mortality. However, only a few small older studies have examined Tv antibody persistence over time, all of which were composed mainly of female patients. Therefore, we examined Tv antibody persistence over time, as well as intra-individual variability, among middle- to older-aged men in the Southern Community Cohort Study (SCCS). Methods We tested baseline and repeat plasma specimens (collected 1–3 years later) from 248 male participants for Tv antibodies. We used the same enzyme-linked immunosorbent assay as in previous studies of Tv serostatus and PCa. Results At baseline, 46 (18.5%) participants were seropositive for Tv infection. Seventy-six percent of these men were still seropositive 1–3 years later. A similar proportion of men “seroconverted” (4.0%) as “seroreverted” (4.4%), all of whom had absorbance values near the cut-off point for seropositivity. Overall, substantial agreement was observed between baseline and repeat serostatus (kappa=0.72, 95% confidence interval: 0.60–0.83). Conclusion Tv seropositivity was largely persistent between plasma specimens collected 1–3 years apart from middle- to older-aged men. These high levels of persistence are similar to those observed for other sexually transmitted infections frequently investigated in relation to PCa.