Vaccination with epimastigotes of different strains of Trypanosoma rangeli protects mice against Trypanosoma cruzi infection.

In our laboratory, we have developed a model of vaccination in mice with Trypanosoma rangeli, a non-pathogenic parasite that shares many antigens with Trypanosoma cruzi. The vaccinated mice were protected against infection with virulent T. cruzi. The goal of the present work was to study the protective activity of strains of T. rangeli of different origin, with the aim of analysing whether this protective capacity is a common feature of T. rangeli. BALB/c mice were vaccinated with live or fixed epimastigotes of two T. rangeli strains, Choachi and SC-58. Vaccinated (VM) and control mice (CM) were infected with virulent T. cruzi, Tulahuen strain. The results showed that the levels of parasitemia of VM, vaccinated with the two strains of T. rangeli were significantly lower than those developed in CM. The survival rate of VM was higher than that CM. Histological studies revealed many amastigote nests and severe inflammatory infiltrates in the heart and skeletal muscles of CM, whereas in the VM only moderate lymphomonocytic infiltrates were detected. Altogether, the results of the present work as well as previous studies show that the antigens involved in the protection induced by T. rangeli are expressed in different strains of this parasite. These findings could prove useful in vaccine preparation.