Granulocytes without degranulation: Neutrophil function in granulocyte-depleted cytoplasts

Neutrophils respond to a variety of stimuli by generating superoxide anion, degranulating, and aggregating. Because it has been suggested that fusion of granules with the plasmalemma (degranulation) is necessary for aggregation and superoxide anion generation, the authors have tested whether these responses can be demonstrated in "neutrophilic cytoplasts" (granule-free vesicles of cytoplasm enclosed by plasmalemma). These results demonstrate that degranulation is not a prerequisite for aggregation or superoxide anion generation. The retention of ionic gradients and changes in membrane potential, as measured by DiOC sub(6)(3) fluorescence changes, suggest a fundamental role for ionic movements in activating superoxide anion generation and aggregation.