6533b872fe1ef96bd12d36a6

RESEARCH PRODUCT

Initiation and Modulation of ECF Generation and Secretion from Human Polymorphonuclear NeutrophilsX.

subject

description

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 as the Ca ionophore, antigen antibody complexes and arachidonic acid. The generation of ECF is dose-, time- and temperature-dependent. In each case a low molecular weight mediator (500 daltons) is released which specifically attracts guinea pig or human eosinophils in a modified Boyden chamber. The secretion of ECF is modulated by agents affecting the cyclic nucleotide level within PMNs or by antiphlogistic substances, while ECF itself is inactivated by serum and cell derived factors. The latter inactivator is present within the granules of PMNs. We conclude that various stimuli attract eosinophils to sites of inflammation where they counteract inflammatory reactions.