The antibody response to T. cruzi infection in immunized dogs. An ELISA was performed to evaluate the serum levels (absorbance in optical density at 405 nm) of T. cruzi-specific antibodies at different times. (A) IgG, (B) IgG1, and (C) IgG2. To determine all immunoglubulins, 1 μg/μL of total T. cruzi extract was used, and the anti-dog IgG, IgG1 and IgG2 antibodies (Novus Biologicals) were diluted 1: 10 000 (IgG), 1:5000 (IgG1) and 1:30 000 (IgG2) in blocking buffer. Pre imm: before the immunization, Post imm: 15 days after the last immunization, and Imm & inf: 60 days after the infection in immunized dogs. The values represent the average of triplicate assays ± S.D (* P < 0.05).