Agents and Actions vol. 6 . 1 / 2 / 3 (1976) Birkhauser Verlag, Basel
Dissociation of Phagocytosis, Metabolic Stimulation and Lysosomal Enzyme Release in Human Leukocytes Dirk Roos*, Ira M. Goldstein, Howard B. Kaplan and Gerald Weissmann * Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, P.O. Box 9190, Amsterdam, the Netherlands, and Department of Medicine, New York University Medical Center, 550 First Avenue, New York, N.Y. 10016, U S A
Abstract In this paper studies are reported concerning the relationship between particle binding to the plasma membrane of h u m a n polymorphonuclear leukocytes (PMN's), phagocytosis, generation of oxidative metabolites, and the release of lysosomal enzymes by these cells. Superoxide (02-) generation by, and lysosomal e n z y m e release from, normal P M N ' s and cytochalasin B-treated cells were measured. W e have found that neither phagocytosis nor lysosomal degranulation are prerequisites for enhanced 02generation. Cytochalasin B-treated P M N ' s , incapable of ingesting particles but still able to bind particles to membrane receptors, generated enhanced amounts of 02- when treated with serum-treated zymosan (STZ), a C3b receptor stimulus, or with aggregated IgG (agg IgG), an Fc receptor stimulus. Moreover, the soluble stimulators complement component C5a, phorbol myristate acetate (PMA), and calcium ions in the presence of the ionophore A23187, also increased the O2- production of these cells. In all cases a time and dose-dependent stimulation was found of both the O2~ generation and the lysosomal enzyme release, but there was no correlation between ability of any stimulus to provoke enzyme release and its ability to stimulate O2~ generation. W h e n P M N ' s were preincubated with 5 • 10-4 M hydrocortisone-Na-suecinate, lysosomal enzyme exocytosis with the immune reactants was inhibited 16-35%. Hydrocortisone also inhibited 02- generation, except when S T Z was used as the stimulus. Thus, in the case of stimulation of functional processes of P M N ' s via the C3b receptor, hydrocortisone inhibits membrane fusion without interfering with one of the early biochemical events (02 production).
microorganisms, among them oxidative metabolites like superoxide (02-) and hydrogen peroxide, and lysosomal enzymes. During the process of phagocytosis, these cellular products are in part released into the medium surrounding the cells, thus causing extracellular killing and degradation as well as tissue injury in inflammatory reactions. At present, few data are available as to the relation between particle binding to the PMN plasma membrane receptors, phagocytosis, generation of oxidative metabolites, and release of lysosomal enzymes by these cells. Therefore, we have studied the production of superoxide and the release of lysosomal enzymes by PMN's rendered incapable of particle ingestion with cytochalasin B, and stimulated by particulate and soluble immune reactants. Figures 1 and 2 show that PMN's incubated without stimulants generated only very little SUPEROXIDEGENERATION BY HUMAN PMN's 12.0 lO.O-q
Human peripheral blood polymorphonuclear leukocytes rely on a number of different mechanisms for the killing and degradation of
. * Financially supported by a travel grant from the Netherlands Organization for the Advancement of Pure Research (Z.W.O.).
m Normol PMNS ell C;~'ocko/aslnB PMN~ I I Yo~rox,do Z ~ a s e * Pv~Co~Wols r
Comols j UZymo,~a~ n~l I AggIgG I Serum-heated CSa "Native"IgG Zvmosan
D i s s o c i a t i o n o f Phagocytosis, M e t a b o l i c S t i m u l a t i o n a n d L y s o s o m a l E n z y m e R e l e a s e in H u m a n L e u k o c y t e s
,g-GLUCURONIDASE RELEASE FROM HUMAN PMN's
02- and released minimal amounts of lysosomal enzyme, both in the absence and in the *~ ~ /Vacma/ PMIV~ presence of cytochalasin B. Incubation with t7 ~ C~,tocholosm B PMIV's STZ, a C3b receptor stimulus, complement // 9 P~.Cant~Is