Inhibition of phagocytosis of human macrophages induced by airborne particulates.

Human monocyte-derived macrophages isolated from peripheral blood were treated with different extracts of airborne particulates collected in the highly industrialized Rhine-Ruhr area. All tested extracts showed a substantial impairment of phagocytosis by inhibition of phagocytic activity as well as phagocytic capacity, while cell viability was rather well maintained. Significant reduction of phagocytosis already appeared at a concentration equivalent to extracted particulates from 3.8 m3 air. Having properties of alveolar macrophages, human monocyte-derived macrophage cultures may offer a reliable in vitro model for assessment of pulmonary toxicity by respirable pollutants.