The role of nitrogen oxides as effector molecules of parasite killing.

The many years of effort in the attempt to identify the effector molecules of lymphokineactivated macrophages have recently come to fruition with the discovery of immuneactive nitrogen oxide. Here, Stephanie James and John Hibbs discuss the novel mammalian biochemical pathways for the synthesis of inorganic nitrogen oxides that mediate antibody-independent killing of infectious agents as well as of tumor cells. Interaction with nitrogen oxides causes iron loss from critical target enzymes in invading organisms, resulting in metabolic failure of extracellular and even of intracellular parasites of the macrophages themselves.