Role of Excited Oxygen Species

Polymorphonuclear leukocytes (PMN) were stimulated with phorbol myristate acetate (PMA) and N-formyl-methionyl-leucyl phenylalanmne (FMLP) to clarify the role of excited oxygen species in inducing changes of membrane fluidity. Membrane fluidity was as-sessed by the excimer-forming lipid technique using pyrenedecanoic acid and flow cy-tometry. Membrane fluidity of PMN decreased following stimulation with PMA, and the extent of decrease was both time- and dose-dependent. FMLP at 10 M induced a de-crease, while FMLP at iO M induced a rapid increase. On stimulation with iO M FMLP as well as in a resting condition, the change of membrane fluidity of PMN from patients with chronic granulomatous disease (CGD) was similar to that of normal PMN. Mowever, on stimulation with PMA or iO M FMLP, CGD PMN did not show a significant decrease. In addition, normal PMN incubated with catalase inhibited the decrease. These findings suggest that the generation of excited oxygen species, particularly of M202, is important in inducing a decrease of PMN membrane fluidity. Key words: chronic granulomatous disease, flow cytometr