In macrophages activated before infection, ROS is detrimental to T. cruzi infection.

Macrophages activated with LPS and IFNγ before infection eliminate phagocytosed T. cruzi CL-Brener by producing peroxynitrite. When the production of peroxynitrite is impaired by inhibiting NOX2-derived ROS with apocynin (right before the infection or after) or when T. cruzi expresses TcCPX, an enzyme that degrades peroxynitrite, the resulting parasite burden is increased [52]. IFNγ, interferon gamma; LPS, lipopolysaccharide; ROS, reactive oxygen species; TcCPX, triparedoxin peroxidase.