Histaminase release from human eosinophils.

Phagocytosis of opsonized zymosan by human eosinophils results in a dose-dependent noncytotoxic release of histaminase as well as arylsulfatase and beta-glucuronidase. The calcium ionophore A23187 also stimulates release of eosinophil histaminase at concentrations of ionophore which barely release arylsulfatase and beta-glucuronidase. Zymosan-induced histaminase release from eosinophils but not from neutrophils was abolished or markedly reduced in the presence of cytochalasin B, suggesting a difference in the mechanisms of histaminase release from the two granulocyte cell types.