Chemotactic activity of guinea pig eosinophils for the ECF-A acidic tetrapeptides, histamine, histamine metabolites, and the effect of H1- and H2-receptor antagonists.
Histamine and one of its major metabolites, imidazoleacetic acid, were selectively chemotactic for guinea pig eosinophils, whereas L-histidine, 1,4-methylimidazoleacetic acid, 1,4-methylhistamine and N-acetylhistamine were inactive. The response to histamine was unaffected by concentrations of eosinophils of between 30 and greater than 90% but it was abrogated by preincubation of the cells with histamine prior to assay (self-deactivation). Eosinophilotaxis was also inhibited by H1-(mepyramine-) and H2-)burimamide)-receptor antagonists at high doses (10(-3)m), although at lower concentrations (10(-5) M) inhibition was principally associated with burimamide. The human tetrapeptide, alanine-glycine-serine-glutamic acid, and the analogue, valine-glycine-aspartic acid-glutamic acid, were inactive whereas alanine-glycine-serine-glutamic acid was chemotactic for the guinea pig eosinophil. These results support the concept that the tissue accumulation of eosinophils following anaphylaxis depends on a complex interaction of factors, which in part may be mediated by H2 receptors on the target cells. There may be species differences in the composition of ECF-A.
Chemotactic activity of guinea pig eosinophils for the ECF-A acidic tetrapeptides, histamine, histamine metabolites, and the effect of H1- and H2-receptor antagonists. Histamine and one of its major metabolites, imidazoleacetic acid, were selectively chemotactic for guinea pig eosinophils, whereas L-histidine, 1,4-methylimidazoleacetic acid, 1,4-methylhistamine and N-acetylhistamine were inactive. The response to histamine was unaffected by concentrations of eosinophils of between 30 and greater than 90% but it was abrogated by preincubation of the cells with histamine prior to assay (self-deactivation). Eosinophilotaxis was also inhibited by H1-(mepyramine-) and H2-)burimamide)-receptor antagonists at high doses (10(-3)m), although at lower concentrations (10(-5) M) inhibition was principally associated with burimamide. The human tetrapeptide, alanine-glycine-serine-glutamic acid, and the analogue, valine-glycine-aspartic acid-glutamic acid, were inactive whereas alanine-glycine-serine-glutamic acid was chemotactic for the guinea pig eosinophil. These results support the concept that the tissue accumulation of eosinophils following anaphylaxis depends on a complex interaction of factors, which in part may be mediated by H2 receptors on the target cells. There may be species differences in the composition of ECF-A.