In order to detect T. gondii forms on paraffin-embedded brain tissue sections of mice chronically infected with T. gondii ME-49 strain [42] , we carried out an immunohistochemical assay by using IgY anti-STAg as primary antibodies. Brain sections were deparaffinized and incubated with specific IgY (30 mg/mL) diluted in PBS for 30 min at 37uC. After washing, slides were incubated with rabbit anti-IgY labeled with fluorescein isothiocyanate (FITC, Sigma) diluted 1:300 in addition to DAPI for 60 min at 37uC. Slides were mounted with carbonate-buffered glycerin (pH 9.0) and read at an inverted fluorescence microscopy system (FSX-100, Olympus, Tokyo, Japan).