FIG. 1.

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 (○, •).