Trypanosoma cruzi: polypeptide markers of epimastigotes and trypomastigotes

We compared the major polypeptides of epimastigotes and trypomastigotes of T. cruzi, by submitting total parasite lysates to electrophoresis in polyacrylamide gels (SDS-PAGE), protein staining with Coomassie brilliant blue, laser densitometry, or immunoblotting with sera derived from infected individuals (Chagas' disease). Epimastigotes and trypomastigotes displayed extensive homology, the differences being quantitative, except for a trypomastigote-specific band of Mr 75,000 which reacted with chagasic sera. Immunoblotting with chagasic sera confirmed the electrophoretic homology of epimastigotes and trypomastigotes. Upon antigenic dilution, a cluster of antigenic bands in the range of Mr 150,000 to 75,000 prevailed in the trypomastigotes, whereas the epimastigotes displayed more abundance of antigenic bands in the range of Mr 72,000 to 36,000.