Lytic effects of Actinobacillus actinomycetemcomitans leukotoxin on human neutrophil cytoplasts

Actinobacillus actinomycetemcomitans leukotoxin lysed human neutrophil cytoplasts. The reaction was associated with a rapid influx of extracellular calcium, a collapse in membrane potential, release of lactate dehydrogenase, and overt disintegration of the plasma membrane. These functional and structural alterations in the plasmalemma of neutrophil cytoplasts reinforce the hypothesis that A. actinomycetemcomitans leukotoxin acts as a pore-forming, membranolytic agent and indicate that neutrophil cytoplasts are useful tools in studying the biology of membrane-active toxins.