Soluble Trichomonas vaginalis antigens in cell-free culture supernatants.

Trichomonad proteins present in cell-free supernatants from logarithmic phase cultures of a pathogenic strain of Trichomonas vaginalis were detected with enzyme-linked immunosorbent assay employing antibody from mice and rabbit antisera. Numerous immunogenic membrane proteins of T. vaginalis were identified by immunoblotting of culture filtrate with rabbit antisera. Released membrane antigens ranging in molecular weight from 30 000 to 300 000 under reducing conditions were also detected in radioimmunoprecipitation assays using growth medium from mid-logarithmic phase organisms which were extrinsically labeled. Parallel experiments using [3H]thymidine-labeled T. vaginalis demonstrated that lysis was not solely responsible for the presence of parasite proteins in growth medium.