Volume - Dependent Human Blood Polymorphonuclear Leukocyte

H UMAN PERIPHERAL BLOOD polymorphonuclear leukocytes (PMNs) possess surface receptors for a variety of ligands which, if bound, lead to its activation.’ Upon binding the ligand, PMNs will undergo membrane potential changes,6 reduce molecular oxygen,7 aggregate,8’9 release granule contents,7 adhere to certain surfaces,’#{176} phagocytize,” and move or chemotax.’2 Recently, the data that these responses represent cumulative activity of a homogeneous population of PMNs has been questioned. Using a modification of the method of Wong and Wilson,3 Klempner and Gallin showed that 80% of circulating PMNs formed rosettes with lgG-coated erythrocytes. The rosette-positive cells were more adherent to nylon wool and had greater phagocytic activity and killing of Staphylococcus aureus cornpared to rosette-negative PMNs.’3 Fanger et al reported heterogeneity of PMNs with respect to binding of IgA.’4 Broxrneyer et al demonstrated that PMNs forming rosettes with IgG-coated sheep erythrocytes contain lactoferrin, which inhibited formation of colony-stimulating activity from human rnonocytes, whereas the lactoferrin from nonrosetting PMNs was not inhibitory.’5 Seligmann et al have shown that PMNs stimulated with the chemotactic peptide fMet-Leu-Phe (fMLP) demonstrate a bimodal distribution of membrane depolarization compared to a homogeneous response with phorbol myristate acetate (PMA) as the stimulant.’6 Howard, using single cell video analysis of PMN locomotion, has revealed PMN heterogeneity with respect to speed of cell movement.’7 Harvath and Leonard studied PMN chemotaxis to several agents, including fMLP, to clearly show the presence of two populations, one that did and one that did not chemotax. These two populations, however, had similar binding for the chemotactic peptide IMLP.’8 Ball et al’9 and Clement et al2#{176} both demonstrated PMN subpopulations by using monoclonal antibody binding to the resting cells. However, no functional differences have been seen. Finally, Seligmann et al showed heterogeneity of PMNs with tions. A positive correlation exists for PMN size and superoxide anion release upon stimulation with f-MetLeu-Phe or phorbol myristate acetate. Total granule contents were also noted to be greater in larger PMN fractions. with a constant percent of release upon stimulation. The implications of these findings are discussed. iS 1985 by Grune & Stratton, Inc.