Cytochalasin E-Induced Oxidative Metabolism in Polymorphonuclear Leukocytes

Abstract

The extent of the cyanide-resistent oxidative burst of polymorphonuclear leukocytes after stimulation with cytochalasin E was shown to depend markedly on the osmolarity of the cell-suspension medium. With granulocyte concentrations up to 2 × 10⁶ cells/ml, optimal oxygen consumption and releases of H₂O₂ and superoxide anions were reached at 180 mOsmol and 2 × 10⁻⁵M cytochalasin E. After removal of unbound activator, the cellular oxidative activity remained unaltered and continued to depend on the used osmotic conditions. It is proposed that binding of cytochalasin to the plasma membrane induces an irreversible activation of the oxidative system, whereas the resulting metabolic activity depends on conformational changes in the plasma membrane.