Phenotypes and protein-epitope phenotypic variation among fresh isolates of Trichomonas vaginalis

Abstract

Fresh isolates of Trichomonas vaginalis were examined for reactions to a panel of five monoclonal antibodies (MAbs). Four MAbs (C20A3, DM126, DM116, and C55) were to distinct surface immunogens and one MAb (L64) was to a cytoplasmic component. The fresh isolates were evaluated by indirect immunofluorescence (IF), immunoblotting, and radioimmunoprecipitation. IF assay with C20A3 MAb gave isolates which were homogeneous nonstaining (negative [Neg] phenotype) and isolates which were heterogeneous staining and nonstaining (positive [Pos] and Neg phenotype, respectively) organisms. Immunoblotting and radioimmunoprecipitation assays revealed that surface phenotypic heterogeneity among isolates with C20A3 MAb was due to the presence or absence of the immunogen from the parasite surface. IF assay with DM126 MAb also gave Pos and Neg phenotypes among parasites of some isolates. All of the isolates were always Neg phenotype with DM116 and C55 MAbs. The occurrence of Neg phenotype organisms with DM126, DM116, and C55 was due to epitope inaccessibility to their respective MAbs and not to the absence of the immunogen from trichomonal membranes. All isolates possessed the cytoplasmic protein recognized by L64 MAb. Paired isolates (taken 5 to 6 days apart) from 24 women were also studied. Four of the 24 paired isolates (16%) had different phenotype distributions at the two timepoints for C20A3. Fresh isolates also underwent phenotypic variation during in vitro growth and multiplication, as determined with C20A3. Also, 7 of the 24 paired isolates demonstrated dramatic changes in the accessibility of DM126 MAb to epitope binding. Lastly, 55 (90%) of 60 serum samples from patients with trichomoniasis evaluated in this study possessed antibody to the C20A3 reactive molecule. The data show that the fresh T. vaginalis isolates were predominantly Neg phenotype and confirm the occurrence of protein and epitope phenotypic variation for major immunogens among fresh isolates of the pathogenic human trichomonads.

The mitotic spindle and associated membranes in the closed mitosis of trichomonads

“…The K strain of Tritrichomonas foetus was isolated by Dr. H. Guida (Embrapa, Rio de Janeiro, Brazil) from the urogenital tract of a bull. T. vaginalis 347 strain was isolated as described previously (Alderete et al, 1987). Both cultures have been maintained in TYM Diamond's medium (Diamond, 1957).…”

Trichomonas vaginalis phenotypic variation occurs only among trichomonads infected with the double-stranded RNA virus.

“…More recent studies examining the phenotypes of fresh isolates of T. vaginalis (3, 4) confirmed the presence of only two types of parasite populations. On the basis of mAb reactivity via indirect immunofluorescence, isolates comprised homogeneous, negative phenotype trichomonads or heterogeneous populations containing both positive and negative phenotype trichomonads (3,4). Isolates that were stable negative phenotype populations did not undergo phenotypic variation (3,4).…”

“…On the basis of mAb reactivity via indirect immunofluorescence, isolates comprised homogeneous, negative phenotype trichomonads or heterogeneous populations containing both positive and negative phenotype trichomonads (3,4). Isolates that were stable negative phenotype populations did not undergo phenotypic variation (3,4). However, purified subpopulations of positive and negative phenotype trichomonads newly fractionated from the heterogeneous parents were both capable of phenotypic variation upon further in vitro cultivation (3,4).Another recent and as yet poorly understood observation that may be relevant to the biology of this host-parasite relationship is the presence of a virus-encoded double-stranded ribonucleic acid (dsRNA)' among some but not all isolates of T. vaginalis (5-7) .…”

“…Isolates that were stable negative phenotype populations did not undergo phenotypic variation (3,4). However, purified subpopulations of positive and negative phenotype trichomonads newly fractionated from the heterogeneous parents were both capable of phenotypic variation upon further in vitro cultivation (3,4).…”

Trichomonas vaginalis: observation of coexistence of multiple viruses in the same isolate

“…One-half of T. vaginalis clinical isolates harbor a dsRNA virus [5,10], and the virus can be lost during batch cultivation, showing that infection permits environmental pressure for harboring of the virus or selection for virusharboring trichomonads. Importantly, the presence of T. vaginalis dsRNA virus was found to correlate with the property of phenotypic variation de¢ned as surface versus non-surface expression of a highly immunogenic protein termed P270 [11,12]. Recently, we demonstrated that large spherical viruses ranging in size from 83 to 104 nm were detectable in the cytoplasm and near the Golgi complex of dsRNA virus-positive trichomonads (M. Benchimol et al, submitted).…”