Chagas' disease is caused by the Trypanosoma cruzi (T. cruzi) and the detection of anti-T. cruzi antibodies in the serum is a method for diagnosis of the disease. In this work, indirect ELISA was optimized for detection of antibodies in patients' sera with Chagas' disease using Tc85-11 protein (Ag) from the trypomastigote surface of the parasite. The full factorial design for optimization of the experimental conditions was carried out for the incubation time, dilutions of Ag (0.08 mg mL-1), primary antibody (Ac) and anti-IgG conjugated with peroxidase (Ac*) parameters. The best results were obtained with the following conditions: 0.14 mg Ag/well, 60 min incubation time, dilutions of 1:35 and 1:1000 for Ac and Ac*, respectively. The cut off value was A450nm = 0.371. The indirect ELISA was applied to sera Chagas' disease infected patients samples and patients with different systemic diseases. Tc85-11 protein, which is involved in the adhesion of the parasite to host cell, is also suitable for serological diagnosis of Chagas' disease.
T. cruzi; Tc85-11; ELISA; Chagas' disease
