Biological and Chemical Characterization of Eosinophil Chemotactic Factors from Human Leukocytes

From Eosinophil Chemotactic Factor of Anaphylaxis to Leukotriene B₄ – Chemistry, Biology and Functional Significance of Eosinophil Chemotactic Leukotrienes in Dermatology

“…PAF is also retained primarily within cells while LTB4 is secreted mostly into the cell environ ment [50], Further arguments against PAF contributing to the biological activity in the ECF preparation are the total suppression of ECF generation by 5-lipoxygenase inhibitors which have no effect on PAF production and the parallel biological activity of ECF and LTB4 towards guinea pig eosinophils which do not respond to PAF. A final resolution of this issue will however on ly come through more extensive studies of PAF in rela tion to LTB4, also in vivo where both factors might act synergistically, as they do in vitro during PMN chemotaxis [16].…”

“…There is currently unanimity about the ability of a number of factors to induce eosino phil migration, as listed in table 1. Eosinophil chemotactic factor (ECF-A) (A = anaphylaxis) was at one time thought to be identical to specific tetrapeptides [15] which were however subsequently found to be inactive by others [16]. Platelet activating factor (PAF) and NFMLP are chemotactically active only against eosinophils from patients with specific diseases [10,17], Guinea pig peritoneal eosinophils do not repond to PAF at all [16], The present review is intended to focus on ECF and its relationship to LTB4 and its metabolites.…”

“…All of these agents have been described to inhibit LTB4 generation in a dose-dependent fashion. We have been able to suppress similarly the generation of ECF from PMN [16], eosinophils [30], monocytes [5], mast cells [31] and keratinocytes [6] by those agents. Indomethacin, an inhibitor of prostaglandin generation from arachidonic acid via a cyclooxygenase, was ineffective or slightly enhancing under the same conditions.…”

Comparative Studies of Human Eosinophil Migration towards Platelet-Activating Factor and Leukotriene B₄

“…1,2], their relative and selective role in the recruit ment of eosinophils to tissue sites is a matter of con troversy. One possible reason for the divergent Find ings in the literature may be species-or disease-spe cific differences in the responsiveness of the cells.…”

“…One possible reason for the divergent Find ings in the literature may be species-or disease-spe cific differences in the responsiveness of the cells. For example, guinea pig eosinophils respond to leuko triene B4 (LTB4), both in vivo and in vitro [2,3], while platelet-activating factor (PAF) induces only little in vitro, but good in vivo migration of eosinophils in that species [2,4], the latter being due to secondary, platelet-related events [4], With human eosinophils, on the other hand, PAF has been reported to be a po tent chemoattractant both in vivo and in vitro [5,6]. In the present investigation, we have tried to confirm these data with cells from a variety of patients with dermatological diseases with low and high eosinophil counts.…”