A number of other studies showed that DNA vaccines encoding various antigens could induce significant protection against T. cruzi infection, as evidenced by decreased parasitemia and improved survival of vaccinated mice (Table 3 ). In addition, a few studies also presented evidence of a reduction in cardiac tissue damage and inflammation at the histopathologic level [87, 97] . Furthermore, T cell analysis confirmed that protection relied on CD8 + T cells [84, 91] and recent studies showed that these cells were very rapidly activated following infection of mice immunized with DNA vaccines [101] . DNA vaccines based on defined T cell epitopes from TS antigen have also been tested and it was found that 6 Journal of Biomedicine and Biotechnology IM: intramuscular; CTL: cytolytic activity; −: no protection; +: little protection; ++: fair protection; +++: very good protection.