Early Biochemical Responses of the Neutrophil to Chemoattractants

Abstract

Chemotactic factors act on neutrophils to induce a displacement of bound intracellular calcium resulting in a transient increase in free cytoplasmic calcium. The increased calcium activates a phospholipase, releasing arachidonic acid. The lipoxygenase system of the neutrophil metabolizes the arachidonic acid to yield products that increase the neutrophil membrane permeability to calcium. In the presence of external calcium, the increased permeability results in an influx of calcium into the cell. Under many circumstances, the increase in free cytoplasmic calcium ultimately results in the various neutrophil responses induced by chemotactic factors. Under other circumstances, however, the above scheme appears not to be implicated or is involved only to a limited extent in neutrophil responses.