Release of eosinophil chemotactic factor from human polymorphonuclear neutrophils by calcium ionophore A23187 and phagocytosis

Abstract

THE number of mediators assumed to be important in the pathogenesis of acute allergic reactions has increased considerably recently. At the outset, Dale¹ suggested that histamine was the critical feature of such responses; then a role for the slow reacting substance of anaphylaxis (SRS-A) was suggested by Brocklehurst², one for the eosinophil chemotactic factor of anaphylaxis (ECF-A) by Kay and Austen^3,4 and more recently a kallikrein-like molecule has been described⁵. Whether preformed, like histamine, or synthesised after the immune event, like SRS-A, each of these mediators had two features in common. (1) It could be released (in primates) only after an IgE antibody–antigen interaction and (2) the cell of origin was the mast cell or the basophil. These generalisations can no longer be accepted. We have described the generation and release of SRS-A from human polymorphonuclear neutrophils (PMN) by the calcium ionophore A23187 (ref. 6), and we report here ionophore-induced release of eosinophil chemotactic factor (ECF) from that cell type. More importantly, we have been able to demonstrate that this mediator can be released by normal human PMN during phagocytosis. (We prefer to call the leukocyte-derived factor described here and in our previous publications ECF for two reasons : first, ECF is not associated only with anaphylaxis, and second, complete biochemical identity with the previously described ECF-A has not been proved.)