Eosinophil Chemotactic Factor (ECF)

Abstract

Eosinophil chemotactic factor (ECF) can be released from human peripheral leukocytes by an IgE-anti-IgE reaction, by the calcium ionophore A 23187 and during phagocytosis. Supernatants and sonicates of unstimulated cells contain little or no ECF. On stimulation, however, ECF activity increases in the cells and even more so in the supernatants. This holds for purified neutrophils (PMNs) as well as for basophil-containing mononuclear cell preparations. These findings contrast with those in lung homogenates, where ECF-A is present in mast cells in a preformed state. On chromatographic analysis, the ECF present within cells does not differ from that released into the supernatant. For the generation of ECF, calcium and an intact cell are necessary. Inhibition of deoxyribo-nucleic acid (DNA) and protein synthesis do not affect ECF generation or release. The metabolic inhibitor, 2-deoxyglucose (2-DG), suppresses ECF activity in leukocyte supernatants to a greater extent than in the cell pellets while the reserve is true for colchicine. This further confirms that ECF is not preformed within cells and that its generation and release are two active, distinct metabolic processes.