Avaliação da imunidade humoral de poliantígenos de Trypanosoma cruzi associados ao Adjuvante Incompleto de Freund em modelo murino

Abstract

Chagas disease, caused by the protozoan Trypanosoma cruzi, remains one of the important public health challenges in the Americas, especially due to the absence of an effective vaccine and the limitations of current treatments, mainly during the chronic phase. In this context, the present study evaluated the murine humoral immune response induced by recombinant chimeric antigens (IBMP-8.1, IBMP-8.2, IBMP-8.3, and IBMP-8.4) of T. cruzi, in comparison to the crude protein extract of T. cruzi (Y strain – DTU II), formulated with Incomplete Freund’s Adjuvant (IFA). BALB/c mice, both males and females, were immunized subcutaneously with two doses, according to the antigen used, all emulsified with IFA. Serum polyclonal antibodies immunoglobin G (IgG) and its subclasses (IgG1, IgG2a, IgG2b, and IgG3) was mesuared by an in-house indirect ELISA. The results demonstrated that all IBMP immunogens were able to induce a statistically significant humoral response compared to the crude extract, with particular emphasis on IBMP-8.2 and IBMP-8.4 proteins and the IgG2a and IgG2b subclasses, which possess effector functions essential for the control of intracellular infections.. Furthermore, the booster dose regimen led to an increase in antibody titers and contributed to the maintenance of the humoral response over time. These findings reinforce the potential of IBMP antigens as promising candidates for the immunotherapeutical products development, including vaccines against Chagas disease