FIG. 5.

A/J mice, but not C57BL/6 mice, develop myocarditis upon both T. cruzi infection and myosin immunization. A/J and C57BL/6 mice were infected with 10⁴ T. cruzi trypomastigotes (infected) or immunized with 300 μg of myosin in CFA (immunized). At 21 d.p.i., cardiac sections from these mice were stained with hematoxylin and eosin. Representative sections are shown. Infected (five of five) and immunized (four of five) A/J mice developed myocarditis while no disease was observed in infected mice (n = 5), immunized C57BL/6 mice (n = 5), or any of the controls, A/J and C57BL/6 mice injected with PBS or immunized with PBS-CFA (four mice per control group). Arrowheads indicate pseudocysts. Bars, 50 μm.