The initial contact between the lectin and neutrophil receptors promotes CR3 expression by neutrophils, and then the interaction of this molecule with iC3b induces neutrophil degranulation. It is likely that neutrophils are activated due to the recognition by TLR-2 and TLR-4 of lipopeptidophosphoglycan (LPPG) from E. histolytica. Activated neutrophils undergo an “oxidative burst” that results in an increased production of superoxide (O₂⁻) by the NADPH-oxidase system. Superoxide dismutase (SOD) rapidly converts O₂⁻ to hydrogen peroxide (H₂O₂, a highly oxidizing agent), and to the substrate of MPO for the formation of hypochlorous acid (HOCl). During this oxidative burst, neutrophils express high levels of iNOS, causing an increase in •NO. Another powerful oxidant is peroxynitrite, formed by the reaction of •NO and O₂•−.