Recombinant human interleukin 5 is a selective eosinophil chemoattractant

Abstract

Human recombinant interleukin (IL) induced migration across polycarbonate filters of human peripheral blood eosinophils. The contribution of chemotaxis vs. chemokinesis was investigated using a checkerboard design with both polycarbonate and nitrocellulose filters. When different cytokine concentrations were seeded above and below the filter, maximal induction of migration required a positive concentration gradient between the lower and upper compartments of the chamber, though some gradient-independent augmentation of migration occurred. These results indicate that induction of eosinophil migration across filter involves actual chemotaxis. The effect of IL 5 was selective for eosinophils with no effect on neutrophils and monocytes. Conversely, granulocyte-macrophage colony-stimulating factor elicited migration of both eosinophils and neutrophils. Thus, human IL 5 is a potent and selective chemoattractant for human eosinophils. Eosinophils are selectively localized in tissues under a variety of physiological and pathological conditions. Locally produced IL 5 may play a role in the selective recruitment of eosinophils from the blood compartment.