FIG. 1.
(A) Immunolocalization of p30-p60, p22, and p97 antigens in T. gondii tachyzoites by A3A4, A4D12, and 1B8 MAbs, respectively, in IFAT. As negative control, an irrelevant mouse IgG isotype was used instead of MAbs, followed by addition of fluorescein isothiocyanate-labeled goat anti-mouse IgG. (B) Immunoblotting of T. gondii total lysate separated in 10% SDS-polyacrylamide gel electrophoresis gel in the absence (−) or presence (+) of 10% 2ME and probed with 1B8, A3A4, and A4D12 MAbs. Standards of molecular mass (Mr) expressed in kilodaltons (kDa) are indicated on the left. Antigens (p97, p30-p60, and p22) recognized by respective MAbs are shown on the right. (C) Inhibition ELISA performed with A3A4, A4D12, or 1B8 MAbs in STAg-coated microplates incubated with a panel of seropositive or seronegative human sera previously analyzed by indirect ELISA for IgG to T. gondii, evaluating the capacities of these samples to compete with MAbs.