Human monocyte-derived macrophage cultures: An alternative test system for the detection of pulmonary toxicity induced by inhaled particulate pollutants

Abstract

Alveolar macrophages are major target cells for toxicity from inhaled particulates. To investigate pulmonary toxicity induced by airborne particulates a phagocytosis assay using human monocyte-derived macrophage cultures was used. Monocytes were isolated from peripheral blood and cultured for 10–14 days. During this period the monocytes differentiated to macrophages. After treatment with various concentrations of different samples of airborne particulate matter, phagocytosis was induced by the addition of Polychromatic Fluoresbrite Microspheres at a cell/particle ratio of 1:10. Phagocytosis was assessed from the determination of phagocytic activity (% cells showing phagocytosis) and of phagocytic capacity (number of phagocytized particles/cell). A concentration-dependent reduction of phagocytic activity and capacity was observed, while cell viability was not greatly affected as compared with the control. These results were in good agreement with those obtained from in vivo inhalation experiments with rodents as well as with those using rat alveolar macrophages obtained after bronchoalveolar lavage and treated in vitro with extracts of particulate matter. Therefore, it is suggested that the use of human monocyte-derived macrophage cultures represents a promising in vitro test system for the evaluation of pulmonary toxicity induced by particulate pollutants.