Immunological and pathological responses in Balb/c mice induced by genetic administration of Tc13 Tul antigen of Trypanosoma cruzi

GARCIA, GA; ARNAIZ, MR; LAUCELLA, SA; ESTEVA, MI; AINCIART, N; RIARTE, A; GARAVAGLIA, PA; FICHERA, LE; RUIZ, AM

PARASITOLOGY

Año: 2006 vol. 132 p. 855 - 866

0031-1820

Tc13 is a trans-sialidase family protein of Trypanosoma cruzi, the aetiological agent of Chagas ’disease. Recently, in vitro studies had suggested that Tc13 might participate in the pathogenesis of the disease. In order to study the role of Tc13 antigens in an in vivo model, we administered plasmid DNA encoding a Tc13 antigen from the Tulahuén strain (Tc13Tul) to BALB/c mice and evaluated the immunological and pathological manifestations as well as the capacity of this antigen to confer protection against T. cruzi infection. Tc13Tul immunization did not elicit a detectable humoral immune response but induced specific memory T-cells with no capacity to produce IFN-g. Five months after DNA-immunization with Tc13Tul, signs of hepatotoxicity and reactive changes in the heart, liver and spleen were observed in 40 –80%of mice. When Tc13Tul 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, Tc13Tul-immunized mice chronically infected with T. cruzi showed a decrease in the severity of heart damage. We conclude that in BALB/c mice, genetic immunization with Tc13Tul mainly induces immune responses associated with pathology.