In parallel, to compare the STAg recognition profile between mammalian and avian hosts, immobilized STAg membranes were probed with sera of experimentally T. gondii immunized mice, diluted 1:100 in 1% skim milk in PBS-T. Primary antibodies were detected by goat anti-mouse IgG antibody labeled with peroxidase (1:1000, Sigma) for 2 h at room temperature. Reaction was revealed with DAB and stopped with distilled water.