Biological aspects of the Trypanosoma cruzi (Dm28c clone) intermediate form, between epimastigote and trypomastigote, obtained in modified liver infusion tryptose (LIT) medium.

We describe some biological characteristics of the Trypanosoma cruzi intermediate form derived from the transformation of epimastigotes to trypomastigotes obtained from cultivation in modified liver infusion tryptose (LIT) medium. The ultrastructural analysis of the intermediate forms in this medium showed the enlargement of the kinetoplast located adjacent to the flagellate nucleus. Some biological characteristics of the intermediate form are similar to trypomastigotes and others to epimastigotes. Despite displaying a similar trypomastigote surface charge, the intermediate forms, like the epimastigotes, are not resistant to complement-mediated lysis. Moreover, the intermediate forms are unable to infect cultured fibroblasts cells but develop limited infections in macrophages.