Human eosinophils, acidic tetrapeptides (ECF-A) and histamine. Interactions in vitro and in vivo

The ECF-A acidic tetrapeptides Val-Gly-Ser-Glu, Ala-Gly-Ser-Glu and the analogue Val-Gly-Asp-Glu were selectively chemotactic for human eosinophils over a narrow dose range although eosinophils from different individuals varied in their dose-response pattern. Histamine abrogated the chemotactic properties of the individual tetrapeptides. When Val-Gly-Ser-Glu and Ala-Gly-Ser-Glu were combined in various concentrations the resultant chemotaxis was either negligible or no greater than that produced when each peptide was tested separately. Val-Gly-Ser-Glu and Ala-Gly-Ser-Glu both promoted eosinophil accumulation when applied to the abraded skin of man or i.d. to the marmoset. Biopsies of marmoset skin revealed that peptide-induced eosinophilia was not associated with mast-cell degranulation. Histamine, which was chemotactic in vitro, did not lead to appreciable eosinophil accumulation in vivo, and combinations of histamine and the acidic tetrapeptides evoked little or no cutaneous eosinophil infiltration either in man or the marmoset. These studies suggest that there is a complex interaction between histamine and the ECF-A tetrapeptides; however, the tetrapeptides alone can promote the recruitment and localization of eosinophils by a mechanism apparently independent of mast-cell degranulation.