Alveolar macrophage migration. Influence of lung lining material and acute lung insult.

Migration of alveolar macrophages collected by lavage from normal rhesus monkeys was tested in an under agarose migration system. Lung lining material and serum albumin obtained from normal rhesus monkeys enhanced the random migration of alveolar macrophages. A chemotactic effect for alveolar macrophages was demonstrated in response to lung lining material. Gel filtration of lung lining material using Sephadex G-200 indicated the presence of 4 distinct fractions. Fraction IV, which had a molecular weight of less than 5,000 daltons, had the greatest ability to enhance alveolar macrophage migration. Macrophages obtained from lungs of rhesus monkeys after they breathed an oxidant gas (ozone) for 7 days demonstrated decreases in both the number of cells randomly migrating and the distance they migrated. The addition of normal lung lining material to macrophages exposed to ozone enhanced their random mobility but did not restore migration values to control values. Ozonized lung lining material or rhesus monkey serum did not significantly alter alveolar macrophage migration from that of control lung lining material or serum. These data indicate that components of the acellular lining material of the lung can produce directional migration of alveolar macrophages and may serve to direct the central flow and clearance of macrophages from alveolar regions. Intraluminal alveolar macrophage accumulation during lung insult with ozone appeared to be related more to migration inhibition of resident cells than to recruitment of additional cells by chemotaxis.