Abstract
Alveolar macrophages were obtained from human volunteers, smokers and nonsmokers, by bronchial lavage through a fiberoptic bronchoscope. Cells were incubated in a chemically defined medium containing [(14)C]sucrose (0.36 mM) and varying concentrations of rabbit serum. Pinocytosis was assessed by the cellular uptake of isotope over 30, 75, and 120-min periods. Pinocytic activity of smokers' cells was dependent on serum concentration but always less than the activity of nonsmokers' cells. The degree of pinocytosis by nonsmokers' cells was independent of serum concentration. It is concluded that the decreased level of pinocytic activity in smokers' alveolar macrophages as indicated by the uptake of sucrose in the presence of rabbit serum may represent a form of reticuloendothelial blockade.