Functional activity of enucleated human polymorphonuclear leukocytes.

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Abstract
Enucleated human polymorphonuclear leukocytes (PMN) were prepared by centrifuging isolated ,intact PMN over a discontinuous Ficoll gradient that contained 20 .mu.M cytochalasin B. The enucleated cells (PMN cytoplasts) contained .apprx. 1/3 of the plasma membrane and .apprx. 1/2 of the cytoplasm present in intact PMN. The PMN cytoplasts contained no nucleus and hardly any granules. The volume of the PMN cytoplasts was .apprx. 1/4 of that of the original PMN. PMN cytoplasts (> 90%) had an outside-out topography of the plasma membrane. Cytoplasts prepared from resting PMN did not generate superoxide radicals (O2-) or H2O2. PMN cytoplasts incubated with opsonized zymosan particles of phorbol-myristate acetate induced a respiratory burst that was qualitatively (O2 consumption, O2- and H2O2 generation) and quantitatively (per unit are of plasma membrane) comparable with that of intact, stimulated PMN. Moreover, at low ratios of bacteria/cells, PMN cytoplasts ingested opsonized Staphylococcus aureus bacteria as well as did intact PMN. At higher ratios, the cytoplasts phagocytosed less well. The killing of these bacteria by PMN cytoplasts was slower than by intact cells. The chemotactic activity of PMN cytoplasts was very low. The PMN apparatus for phagocytosis, generation of bactericidal O2 compounds, and killing of bacteria, as well as the mechanism for recognizing opsonins and activating PMN functions, apparently are parsent in the plasma membrane and cytosol of these cells.