IFNG and infection: For this, naive- or interferon-gamma/lipopolysaccharide- (IFN-γ-LPS) stimulated macrophages (iNOS induction and thus peroxynitrite generation) were infected with Fl-B pre-loaded trypomastigotes at a parasite: macrophage ratio of 10:1, and Fl-B oxidation within the phagosome was measured by flow cytometry 1 hour post-infection (Fig. 4, D and E).