Effect of suramin on trypomastigote forms of Trypanosoma cruzi: changes on cell motility and on the ultrastructure of the flagellum-cell body attachment region.

Suramin has been previously reported to inhibit distinct cell enzymes and to affect the synthesis and distribution of cytoskeleton proteins. Our study indicates that prolonged incubation of Trypanosoma cruzi infected-LLC-MK2 cells in the presence of 500 microM suramin during the intracellular development of the parasite caused morphological changes on trypomastigote forms characterized by a partial or complete detachment of the flagellum from the cell body, besides an accentuated decrease on parasite motility. Immunofluorescence analysis of the region of adhesion between the cell body and the flagellum on trypomastigotes obtained from suramin-treated host cells after the completion of cell cycle did not show any difference in the localization of FAZ antigens recognized by 4D9 and L3B2 monoclonal antibodies despite the presence of a detached flagellum. On the other hand, suramin caused a significant increase on the phenotypic expression of FRA antigen, which was observed throughout the surface of trypomastigotes. Cytochemical localization of cationized ferritin in trypomastigotes obtained from suramin-treated host cells showed that anionic particles gained access to the space between the cell and flagellar membranes, as well as to the flagellar pocket, indicating an alteration on extracellular components of the region of adhesion between the cell body and the flagellum.