Unique determinants of alveolar macrophage spontaneous and chemokinetically stimulated migration

Abstract

The in vitro migration of rabbit alveolar and peritoneal macrophages was quantitated by an agarose well assay which permitted the distinction of chemokinetic and chemotactic patterns of stimulation by rabbit serum, tryptic fragments of the fifth component of complement, and the synthetic peptide formyl-methionyl-phenylalanyl-leucine. The peritoneal macrophages exhibited greater chemotaxis than the alveolar macrophages, but the magnitude of the chemokinetic response of both macrophage populations to each stimulus was much greater than that of the corresponding chemotactic response. Preincubation of macrophages with 2,4-dinitrophenol suppressed the spontaneous and chemokinetic migration of the alveolar macrophages without influencing the migration of the peritoneal macrophages, while iodoacetate inhibited the migration of both types of macrophages. The addition of a crude preparation of surfactant to the macrophages stimulated the migration of both the alveolar and peritoneal populations. Alveolar macrophages are thus not only uniquely adapted to the high oxygen concentrations in their environment, but may perform their surveillance of the pulmonary surfaces more efficiently as a result of the presence of surfactant or related lipoproteins.