EFFECT OF PARTICLE-SIZE ON ALUMINA-INDUCED PRODUCTION OF REACTIVE OXYGEN METABOLITES BY HUMAN-LEUKOCYTES

To assess the role of crystal size in the biologic response, we quantitated the generation of reactive oxygen metabolites in human polymorphonuclear leukocytes (PMNs) or mononuclear leukocytes (MNs) with a chemiluminescence assay using 6 alpha-alumina preparations with average diameters of 0.6, 0.8, 3.2, 7.5, 28 and 68 mu m on the basis of equal weights (1 mg/ml), and also on the basis of surface areas (100 cm(2)/ml). On an equal weight alumina particles induced PMN chemiluminescence in the following order of magnitude: 3.2 mu m > 7.5 mu m 0.8 mu m > 0.6 mu m > 28 mu m, 68 mu m. The particulates induced MN chemiluminescence: 3.2 mu m > 0.8 mu m > 0.6 mu m > 7.5 mu m > 28 mu m, 68 mu m. On the basis of identical surface areas, alumina elicited PMN chemiluminescence: 3.2 mu m > 7.5 mu m, 0.8 mu m > 0.6 mu m, 28 mu m, 68 mu m. The particulates induced MN chemiluminescence: 3.2 mu m > 0.8 mu m > 0.6 mu m, 7.5 mu m > 28 mu m, 68 mu m. The maximal effect of particle size on the alumina-induced production of reactive oxygen metabolites by human leukocytes was seen at around 3 mu m.