The effect of iron and agar on production of hydrogen peroxide by stimulated and activated mouse peritoneal macrophages.

The effect of iron on H2O2 production by mouse peritoneal macrophages exposed to opsonised zymosan has been investigated. Macrophages elicited with thioglycollate broth produced less H2O2 than macrophages activated by Corynebacterium parvum, and levels were not affected by prior incubation of the cells with 0.1 mM iron nitrilotriacetate. However, preincubation with the iron chelator desferrioxamine (1 mM) reduced H2O2 production by both types of macrophages. Incubation of macrophages with agar, a component of thioglycollate broth, also reduced H2O2 production, particularly by C. parvum-activated macrophages. The results indicate that although iron appears to be necessary for H2O2 production by macrophages, the low level of production by thioglycollate-elicited macrophages is not due to an inadequate level of metabolically utilisable iron, but may be a result of prior ingestion of agar present in the broth.