Trichomonal vaginitis: evaluation of serological tests and identification of immunoreactive surface peptides

An indirect haemagglutination assay (IHA) with polysaccharide and protein antigens of Trichomonas vaginalis and an enzyme linked immunosorbent assay (ELISA) were used to test for antibodies against T vaginalis in 58 women with trichonomal vaginitis and 48 with non-specific vaginitis. Eleven antibody positive sera were used in a radioimmunoprecipitation assay (RIPA) to identify surface peptides that elicited antibody responses in infected women. The serological tests were less sensitive than biological tests (smear examination and culture); antibodies were detected in 22 of the 58 women with trichomonal vaginitis by IHA using polysaccharide as antigen, in 27 by IHA using protein antigen, and in 36 by ELISA. The ELISA was also found to be of low specificity. Only two of the 11 sera tested by RIPA showed positive reactions with surface antigens, which were confirmed by autoradiography.