Immunological and pathological responses in BALB/c mice induced by genetic administration ofTc13 Tul antigen ofTrypanosoma cruzi

Abstract

Tc13 is atrans-sialidase family protein ofTrypanosoma cruzi, the aetiological agent of Chagas' disease. Recently,in vitrostudies had suggested thatTc13 might participate in the pathogenesis of the disease. In order to study the role ofTc13 antigens in anin vivomodel, we administered plasmid DNA encoding aTc13 antigen from the Tulahuén strain (Tc13 Tul) to BALB/c mice and evaluated the immunological and pathological manifestations as well as the capacity of this antigen to confer protection againstT. cruziinfection.Tc13 Tul immunization did not elicit a detectable humoral immune response but induced specific memory T-cells with no capacity to produce IFN-γ. Five months after DNA-immunization withTc13 Tul, signs of hepatotoxicity and reactive changes in the heart, liver and spleen were observed in 40–80% of mice. WhenTc13 Tul DNA-immunized animals were challenged with trypomastigotes, a significant decrease in parasitaemia in early and late acute phase was observed without modification in the survival rate. Surprisingly,Tc13 Tul-immunized mice chronically infected withT. cruzishowed a decrease in the severity of heart damage. We conclude that, in BALB/c mice, genetic immunization withTc13 Tul mainly induces immune responses associated with pathology.