Neutrophil iodination reaction induced by fluoride: implications for degranulation and metabolic activation.

Activation of neutrophils by phagocytosis or certain soluble stimuli results in a burst of oxidative metabolism and in degranulation. Fluoride is known to trigger the metabolic burst. but degranulation has not been reported. lodination of protein by F -activated human PMN was demonstrated by measuring TCA-precipitable 1251. lodination was dependent on H20,. since it was inhibited by catalase. enhanced by superoxide dismutase. and absent in PMN from patients with chronic granulomatous disease. Dependence on myeloperoxidase was indicated by an inhibitory effect of azide and cyanide and by the absence of iodination in myeloperoxidase-deficient PMN. Soluble extracellular protein was the predominant substrate for iodination. suggesting secretion of myeloperoxidase and H,O,. Maximum iodination occurred after a 60-mm exposure of PMN to 20-30 mM fluoride. At greater than 30 mM F . there