CYTOKINEPLASTS AND U-CYTOPLASTS FROM HUMAN POLYMORPHONUCLEAR LEUKOCYTES - ROLE OF GRANULE-POOR MOTILE FRAGMENTS IN THE ANALYSIS OF CELL PHYSIOLOGY

We have been using granule-poor anucleate fragments - cytokineplasts a nd U-cytopiasts - released from human peripheral blood polymorphonucle ar leukocytes (granulocytes; PMN) to study cell functions that bear on aspects of the inflammatory response. The work is particularly aimed at the relationships among specific but overlapping areas of leukocyte activity: adherence, locomotion, target recognition, chemotaxis, pene tration of endothelial monolayers, ingestion, the increased metabolic activity that ordinarily accompanies phagocytosis or other cell activa tion processes, degranulation of lysosomal structures, and intracellul ar killing. The ways in which these activities can be separated from o ne another may distinguish obligate interactions from mere concomitanc e, and may reveal the specific pathways by which cell function is alte red. We have found that cytoplasts provide a unique way of looking at the composition and function of the cell's motile and killing machiner y, in greatly simplified systems.