Induction of IL-12 (p40) synthesis by inflammatory
macrophages exposed to live trypomastigotes from different strains of
T. cruzi. Macrophages were cultured in the presence (closed
symbols) or absence (open symbols) of IFN-γ (75 U/ml) and were
exposed to different ratios of live trypomastigotes from various
T. cruzi strains. The levels of IL-12 (p40) in the
supernatant were measured 48 h after macrophage exposure to
parasite. The Gilmar, CL, and J strains were drug-susceptible parasites
(▵, ▴); the Y strain was a partially resistant parasite (□, ■);
and the VL-10 and Colombiana strains were drug-resistant parasites
(○, •).