0000000000653593
AUTHOR
H. Tesch
Generation and release of eosinophil chemotactic factor from human polymorphonuclear neutrophils by arachidonic acid
This study describes the generation and release of an eosinophil chemotactic factor from human polymorphonuclear neutrophils, rat basophilic leukemia cells, and from a lymphocyte monocyte basophil suspension by arachidonic acid (AA). The eosinophil chemotactic factor (ECF) is highly specific for eosinophils and resembles the ECF activity obtained from human polymorpho-nuclear neutrophils after stimulation with the Ca ionophore or during phagocytosis. In this regard, AA-induced ECF represents a biological activity distinct from oxidized AA and its conversion products. AA may therefore have a dual function: it represents an important mechanism of cell activation; as AA is converted into prost…
Generation of an Eosinophilotactic Factor from Human PMNs by Various Mechanisms of Cell Activation
It is well established that an increase in the number of eosinophils both in tissue and in the circulation is a feature of many clinical conditions based on delayed (1,2) and immediate type hypersensitivity reactions (3,4). Since eosinophils have been recognised to exert specific killer function on parasites (5) and to be prominent participants at sites of inflammation, the mechanisms of their chemo-attraction are of major importance. In immediate type hypersensitivity reactions, eosinophils have been demonstrated to counteract the mediators of inflammation such as histamine (6), the SRS-A (7) and the platelet aggregating factor (8).
Phospholipase A2 and arachidonic acid: a common link in the generation of the eosinophil chemotactic factor (ECF) from human PMN by various stimuli.
An eosinophil chemotactic factor (ECF) of low molecular weight can be generated and released from human polymorphonuclear neutrophils by the calcium ionophore, phagocytosis of zymosan particles, arachidonic acid, and phospholipase A2. Since the activation of cells by the ionophore and during the phagocytic event leads to phospholipid turnover, with the subsequent generation of arachidonic acid, it is reasonable that phospholipase A2 represents the common link for ECF production. The kinetics of ECF release by phospholipase A2 is similar to the pattern observed with the various stimuli. After a rapid rise in activity a decline occurred at later times of secretion, suggesting a mechanism of i…
Initiation and Modulation of ECF Generation and Secretion from Human Polymorphonuclear NeutrophilsX.
The primary mediators which are involved in inflammatory processes are histamine, the slow reacting substance of anaphylaxis (SRS-A), the platelet aggregating factor (PAF) and the eosinophil chemotactic factor (ECF). These mediators are primarily localized within mast cells and basophil leucocytes, which represent the target cells of allergic reaction. Binding of IgE to mast cells and basophil leucocytes and addition of the appropriate antigen then leads to the activation of the target cells with a subsequent release of their mediators. SRS and ECF have also been found in a non mast cell source, e.g. in human PMNs. ECF can be generated and released from human PMNs by different stimuli, such…