Functional heterogeneity of isopycnic fractions of rat alveolar macrophages.

Rat alveolar macrophages separated into four isopycnic fractions on Percoll gradients were functionally heterogeneous in bacterial phagocytosis, intracellular killing, superoxide anion release, and lysosomal enzyme activity but not in hydrogen peroxide release. With increasing alveolar macrophage density, phagocytosis, intracellular killing, superoxide anion release, and lysozyme activity increase, and acid hydrolase activity decreases.