Figure 1.

Immunohistochemical staining (IHS) for perforin in heart tissue of C57BL/6 and pfp^−/− mice. The figure shows representative pictures of IHS detection of perforin in the heart tissue sections of (a) non-infected C57BL/6 mouse, (b) Trypanosoma cruzi-infected pfp^−/−, (c) T. cruzi-infected C57BL/6 in absence of the primary anti-perforin antibody and (d) T. cruzi-infected C57BL/6 mice at day 50 postinfection. (e) and (f) are representative heart tissue sections from infected C57BL/6 mice at day 150 postinfection. Perforin-expressing cells are mononuclear cells and perforin is not restricted to the cytoplasm but released onto the adjacent cardiomyocytes (d, arrows head). Panels a, b, c and e, 400×; panels d and f, 1000×. Each experimental group consisted of four analysed mice, in two independent experiments.