Features of Host Cell Invasion by Different Infective Forms of Trypanosoma cruzi

Through its life cycle from the insect vector to mammalian hosts Trypanosoma cruzi has developed clever strategies to reach the intracellular milieu where it grows sheltered from the hosts ’ immune system. We have been interested in several aspects of in vitro interactions of different infective forms of the parasite with cultured mammalian cells. We have observed that not only the classically infective trypomastigotes but also amastigotes, originated from the extracellular differentiation of trypomastigotes, can infect cultured cells. Interestingly, the process of invasion of different parasite infective forms is remarkably distinct and also highly dependent on the host cell type. Key words: Trypanosoma cruzi- cell invasion- amastigote- trypomastigote In the natural course of infection, the infected insect transmits metacyclic trypomastigotes that in-vade mammalian cells, escape the endocytic vacu-ole and transform into rounded amastigote forms. Amastigotes replicate in the cytoplasm, differenti-ate back into trypomastigotes that are released af-ter cell lysis. An alternative sub-cycle can occur in the mammalian host if amastigotes, originated from premature lysis of infected cells (Behbehani 1973