Studies on human leukocyte motility. II. Effects of bacterial endotoxin on leukocyte migration, adhesiveness, and aggregation.

While polymorphonuclear leukocytes appear to play a major role in many of the biologic effects of bacterial endotoxin,1' the mechanism by which endotoxin interacts with these cells is not clear. Recent studies from this laboratory showed that phagocytosis of several different types of particles inhibited neutrophil migration in microhematocrit tubes.8 This inhibition was due to both decreased motility of individual neutrophils participating in phagocytosis and aggregation of leukocytes into clumps. It was subsequently observed that exposure of neutrophils to bacterial endotoxin or immune precipitates produced similar effects. The present studies were undertaken to test the thesis that the changes observed in neutrophil function after incubation with endotoxin result from phagocytosis of endotoxin and represent a general pattern of polymorphonuclear leukocyte response to ingestion of a variety of macromolecular substances.