Functional and metabolic properties of polymorphonuclear leucocytes. I. Observations on the requirements and consequences of particle ingestion

Fate of surface proteins of rabbit polymorphonuclear leukocytes during phagocytosis. II. Internalization of proteins

The distribution of surface proteins during phagocytosis by rabbit peritoneal polymorphonuclear leukocytes was studied to determine whether the proteins of the phagocytic vesicles of these differentiated cells were representative of the entire set of plasma membrane proteins. Phagocytosis of bovine serum albumin-diisodecylphthalate emulsion by lactoperoxidase-iodinated rabbit neutrophils was linear over 15-20 min at a rate of 96 microgram oil/min/mg cell protein. This rate was similar to that of unlabeled cells. Incorporation of cell-associated free iodine by endogenous myeloperoxidase during phagocytosis was inhibited by 1 mM cyanide, which had no effect on the rate of particle uptake. The surface of intact neutrophils contained at least 13 iodinated proteins distinguishable by polyacrylamide gel electrophoresis followed by autoradiography. Isolated phagosomes were deficient in six of these proteins. The plasma membrane fraction of these cells was missing five of these same proteins which, however, were enriched in a dense surface fraction (Willinger, M., and F. R. Frankel. J. Cell Biol. 82: 32-44). When experimental conditions were reversed, and the PMNs were labeled after phagocytosis, these five proteins remained on the cell surface, while at least three of the major proteins found on resting cells were depleted. Incubating the cells with colchicine, which has been shown to affect the distribution of some plasma membrane constituents during phagocytosis, had no effect on the distribution of surface proteins in our system. These results indicate that a nonrandom interiorization of lactoperoxidase-labeled surface proteins of polymorphonuclear leukocytes occurs during phagocytosis.

The influence of some metabolic inhibitors on phagocytic activity of mouse macrophages in vitro

The action of different metabolic inhibitors on phagocytosis by macrophages from mouse peritoneal exudate cultured in vitro was studied. The following metabolic inhibitors were tested: sodium iodoacetate, sodium fluoride, sodium fluoroacetate, sodium malonate, 2-4-dinitrophenol, sodium azide, ouabain and cycloheximide, all at the concentration of 10(-3) M. Iodoacetate caused a strong inhibitory effect on phagocytosis; this observation confirms that glycolysis is the main source of energy for the phagocytic process. On the contrary, fluoride, although it is an effective inhibitor of glycolysis, did not exert any effect. This difference may be explained by the fact that sodium fluoride blocks anaerobic glycolysis only in vitro at an unphysiological temperature (0 degrees C). Fluoroacetate and malonate, two compounds which interfere with the Krebs cycle, did not inhibit phagocytosis, but it is known that the Krebs cycle activity is poorly developed in the macrophagic cells. Sodium azide and 2-4-dinitrophenol, two inhibitors of oxidative phosphorylation, showed an effect on phagocytosis only after 3 h of contact with the cell cultures. Ouabain blocks Na+ and K+ transport across the plasma membrane and, probably, it inhibited phagocytosis by interfering with the movements of the cell membrane. Finally, the mode of action of cycloheximide on phagocytosis is uncertain. This compound inhibits the protein synthesis and, perhaps, it can act by preventing the renewal of the cell membrane.

Phagocytosis: a review

Primitive unicellular organisms depend greatly on internalization of particulate matter for nourishment. In metazoa, this process is further developed to play a major role in mechanisms of defense. This review analyzes, mainly in mammalian systems, the various phenomena surrounding the phagocytic act. Much of the emphasis is placed on experimental work which has recently elucidated some of its features. Both the structural and functional aspects of phagocytosis are considered throughout the review, which is subdivided into an examination of chemotaxis and the various agents inducing it, the mode of recognition of particles to be phagocytized, and the mechanisms of ingestion. The last includes a discussion of the possible means whereby recognition is translated into ingestion, the modes of adhesion of particles onto the surface of phagocytes, the formation and fusion of pseudopodia during engulfment and ingestion, and process and significance of degranulation. In addition, the metabolic changes in phagocytes during the processes of chemotaxis, ingestion, and digestion are described. A discussion of the various ways phagocytes may destroy microorganisms incorporates an appreciation of the importance of the microbicidal action of the acidic environment of the phagosome, the various lysosomal contents, hydrogen peroxide, superoxide, singlet oxygen, and chemiluminescence. The interdependence and interrelationship of the induction and cooperation of these mechanisms are examined.

Termination of the respiratory burst in human neutrophils

Recent evidence has suggested that a particulate O(2) (-)-forming system is responsible for the respiratory burst in activated neutrophils. The respiratory burst is normally a transient event, lasting only 30-60 min. To investigate the mechanism by which the burst is terminated, we examined the O(2) (-)-forming activity of neutrophil particles as a function of time in the presence and absence of agents known to affect the function of intact cells. Measurements of the O(2) (-)-forming capacity of the particles against time of exposure of neutrophils to opsonized zymosan, a potent stimulating agent, revealed a rapid fall in activity when exposure was continued beyond 3 min. Exposure to zymosan under conditions in which the myeloperoxidase system was inactive (i.e., in the presence of myeloperoxidase inhibitors, or in the absence of oxygen) resulted in a substantial increase in the initial O(2) (-)-forming activity of particles from the zymosan-treated cells, but did not prevent the sharp fall in activity seen when zymosan exposure exceeded 10 min. The fall in activity was, however, prevented when activation took place in the presence of cytochalasin B (1.5 mug/ml), an agent thought to act largely by paralyzing the neutrophil through an interaction with its microfilament network.We conclude from these findings that the termination of the respiratory burst results at least in part from the inactivation of the particulate O(2) (-)-forming system. This inactivation involves at least two processes which probably act simultaneously. One is the destruction of the system through the action of myeloperoxidase. The other appears to require active cell motility and is independent of oxygen. The current view holds that the O(2) (-)-forming system of the neutrophil is located in the plasma membrane. It may be that the second process involves the internalization and degradation of this membrane-bound system.

Function of phagocytosis and intracellular killing of peripheral neutrophils in Kawasaki disease

NBT (Nitroblue Tetrazolium) test was performed in 17 patients with Kawasaki disease to examine the function of phagocytosis and intra-cellular killing of neutrophils. The value was high compared to other pediatric patients. Activation with Proteus OX-2 antigen before NBF test showed a significant higher level than other proteus antigens, which correspond in serum level. With previous electronmicroscopic observation of rickettsia-like body in biopsy specimen, these findings suggest the existence of an agent in Kawasaki disease which shares antigenicity with Proteus OX-2.

Modification by metals, sulphydryl reagents and cyanide of the particle stimulated enhancement of oxygen consumption in bovine granulocytes

A simple, rapid method for the isolation of neutrophil-enriched leucocyte suspensions from bovine blood is described. The capacity of these cells to produce a particle stimulated increase in oxygen consumption deteriorated during a period of storage of the cells whilst the viability of the cells remained unchanged. Potassium cyanide inhibited the basal oxygen consumption but enhanced the stimulated respiratory burst. Zinc ions also enhanced this respiratory burst but ferric and manganous ions did not. The lipid-soluble non-haem iron chelator, 4,4,4-trifluoro-1-(2 thienyl)-1,3-butanedione, preferentially inhibited the particle stimulated type of oxygen consumption, as did the sulphydryl reagents, N-ethyl maleimide and diazine dicarboxylic acid bis-dimethyl amide. These data allow us to consider that zinc ions may play a role in the respiratory burst associated with phagocytosis and that iron-sulphur interactions may be important in oxygen consuming reactions.

NADPH-oxidation activities in subcellular fractions isolated from resting or phagocytozing human polymorphonuclears

Using a fluorometric assay for the determination of oxidized pyridine nucleotides (NAD[P]+), total and cyanide-resistant NADPH-oxidative activities have been measured in subcellular fractions isolated from resting and phagocytosing human polymorphonuclears. Enzymatic activies responsible for the oxidation of the NADPH have been recovered in the heavy particles (15,000g/15 min), the low-density particles (100,000g/30 min), and the cytosolic fraction. Stimulation of the cells with opsonized zymosan had a different effect on the NADPH-oxidative activities of these subcellular fractions, which suggests the involvement of various types of enzymatic systems in the oxidation of NADPH. The cytosolic fraction interacted strongly with the enzymatic activities occurring in the sedimentable fractions and is therefore thought to play a central role in the regulation of the activation of the oxidative metabolism associated with phagocytosis.

Bacterial stimulation and granulocyte inhibition of granulopoietic factor production

We attempted to determine the effect of live bacteria (Staphylococcus epidermidis) on granulocyte colony-stimulating-factor production by human peripheral blood mononuclear cells (monocytes and lymphocytes) in vitro. Addition of bacteria to mononuclear-cell cultures enhanced colony-stimulating-factor production by these cells, as assayed on both human and mouse bone marrow. Addition of peripheral blood granulocytes to parallel cultures eliminated this enhancement effect, presumably by bacterial removal or inactivation. These data suggest that micro-organisms may have a pivotal role in granulocyte production and maturation by serving as a stimulus to increase colony-stimulating-factor production and also as negative control through their removal by the newly formed granulocytes.

The influence of some metabolic inhibitors on in vitro phagocytizing macrophages. I. The behaviour of human macrophages

In the present work the uptake of foreign materials by macrophages has been studied in order to elucidate its possible energy-dependent mechanisms. We used monolayer cultures of macrophages from human peripheral venous blood, treated with the following metabolic inhibitors: iodoacetic acid, fluoroacetic acid, sodium fluoride, sodium malonate, sodium azide, 2-4-dinitrophenol, cycloheximide, and ouabain. The test assay was performed by using a zymosan particles suspension in Mc Coy 5 A medium supplemented as follows. The quantitation of phagocytosis was obtained by direct count of intracellular zymosan particles by oil 100X microscopy and the results were submitted to a statistical evaluation. The most effective inhibitor we found was iodoacetate, an inhibitor of anaerobic glycolysis, but fluoride, which acts on the same metabolic pathway at a different site, was quite ineffective. The same ineffectiveness we found for fluoracetate and malonate which act on the Krebs cycle. On the contrary, dinitrophenol (uncoupler of oxidative phosphorylation), azide (inhibitor of cytochrome linked-phosphorylation), ouabain (inhibitor of membrane ATPase activity) and cycloheximide (inhibitor of protein synthesis) give a remarkable decrease of index of phagocytosis after a 3h incubation. In conclusion, we can suppose that the energy-dependent phagocytosis is first depending on transport across the cell membrane (ATPase activity and protein synthesis) and second both on anaerobic glycolysis and oxidative phosphorylation.

Phygocytosis by rabbit polymorphonuclear leukocytes: the effect of albumin and polyamino acids on latex uptake

Albumin in low concentrations (0.0001-0.01 weight percent) was found to be an effective inhibitor of phagocytosis of polystyrene latex beads by rabbit polymorphonuclear leukocytes. Polyglutamic acid proved to be an inhibitor of latex uptake at even lower concentrations. Polylysine stimulates phagocytosis, maximal stimulation occurring at 0.002% polylysine. These findings are discussed with reference to the surface properties of latex particles and leukocytes, and particularly with reference to electrostatic interactions in phagocytosis.

Glucose utilization and role of blood in endotoxin shock

The present study was conducted to explore influences modifying glucose uptake in canine blood administered LD100 E. coli endotoxin. Particular emphasis was given to assay the role of the white blood cell (WBC) in glucose utilization. Significant increases in glucose uptake and lactic acid production, attributed to increased activity of the WBC, were observed 1-3 h after endotoxin was added to blood in vitro. Although a net increase in glucose utilization was noted, endotoxin simultaneously exerted adverse effects by depressing glucose uptake below predicted values (Q10 = 2.12 with LD100 endotoxin vs. 2.78 in saline controls) and increasing WBC mortality rate. Blood from dogs pretreated with sublethal doses of endotoxin in vivo utilized glucose at an accelerated rate when subjected to endotoxin in vitro. Excess glucose was consumed because of elevated numbers of white blood cells although additional glucose requirements after endotoxin were independent of temperature between the ranges of 34-41 degrees C. All animals pretreated with daily sublethal injections of endotoxin for 3 days survived superlethal doses of endotoxin.

The effect of 2-deoxyglucose on guinea pig polymorphonuclear leukocyte phagocytosis

The effects of 2-deoxyglucose (DOG), an inhibitor of glycolysis, on guinea pig polymorphonuclear leukocytes (PMN) obtained from peritoneal exudates was examined. ATP levels in PMN were reduced by 40% by one hour following an incubation with 2-deoxyglucose. When complement (C3) coated 14C-staphylococcus aureus, C3 coated lipopolysaccharide-paraffin oil droplets (LPS-PO), 14C-pneumococcus opsonized with IgG, or albumin coated paraffin oil droplets opsonized with IgG were added to cell suspensions containing DOG, the phagocytizing rate was 1,310+/-55 cpm/5 X 10(6) cells/15 minutes, 6+/-2 microng paraffin oil (PO)/10(7) cells/minute, 2,250+/-175 cpm/1 X 10(6) cells/20 minutes or 0.037+/-0.01 mg PO/10(7) cells/minute compared to control values of 5,970+/-275 cpm/5 X 10(6) cells/15 minutes, 35+/-3 microng PO/10(7) cells/15 minutes, 4,510+/-200 cpm/1 X 10(6) cells/20 minutes and 0.067+/-0.01 mg PO/10(7) cells/minute. In parallel studies the phagocytic index for latex was 0.74+/-0.28 in DOG compared to control of 2.36+/-1.13 and the phagocytic rate of albumin coated paraffin oil droplets was 0.029+/-0.01 mg PO/10(7) PMN/minute in DOG compared to control of 0.048 mg PO/10(7) cells/minute. When ATP levels were maintained by the simultaneous addition of 5 mM glucose or pyruvate to media containing DOG, latex ingestion was improved to 1.15+/-0.3 with glucose and 1.59+/-0.64 with pyruvate and albumin coated particles to 0.045+/-0.01 mg PO/10(7) PMN/minute with pyruvate. There was no improvement in the uptake of either the C3 dependent particles or IgG coated Pneumococci in media containing DOG and glucose and/or pyruvate. Following the removal of DOG from the extracellular medium and the addition of pyruvate or glucose, phagocytosis of C3 dependent LPS-PO was restored to normal values. Neither the binding of C3 or IgG coated particles to the PMN nor the lateral movement of glycoprotein utilizing concanavalin A capping was affected by DOG. Thus, the presence of DOG in the PMN containing adequate amounts of ATP will selectively and reversibly inhibit those surface events required for phagocytosis of C3 and IgG bound particles but not latex particles or albumin particles which non-specifically bind to PMN.

Effects of tobacco smoke on chemotaxis and glucose metabolism of polymorphonuclear leukocytes

The effect of tobacco smoke on in vitro chemotaxis of human polymorphonuclear leukocytes (PMN) was determined. Whole tobacco smoke, gas phase of smoke, and water-soluble fraction were potent inhibitors of PMN chemotaxis. The results indicated that PMN chemotaxis was inhibited in a dose-dependent manner by water-soluble fraction and that this suppression was not a result of cytotoxicity. In an attempt to determine the mechanism of chemotaxis inhibition, the effect of tobacco smoke on glucose metabolism of PMN was studied. Exposure of PMN to whole smoke, gas phase, or water-soluble fraction resulted in an increase (twofold) in glucose catabolism via both glycolysis and the hexose monophosphate shunt, with no apparent effects on the metabolism of glucose via the tricarboxylic acid cycle. These results suggest that the inhibitory effects of tobacco smoke on PMN chemotaxis were not directly attributable to effects on glucose metabolism of these cells. Further, the inhibitory effects of water-soluble fraction on PMN chemotaxis were shown to be largely irreversible and preventable in the presence of cysteine. Thus, the major inhibitory effects of tobacco smoke probably result from the direct action of oxidants and/or thiol-reactive substances on PMN.

The role of lysosomal elastase in the digestion of Escherichia coli proteins by human polymorphonuclear leukocytes: experiments with living leukocytes

Human polymorphonuclear leukocyte (PMN) elastase has been implicated in various pathological conditions. However, its physiological role remains undefined. One possible function of this enzyme may be digestion of bacterial proteins after phagocytosis. To test this hypothesis, we prepared Escherichia coli labeled with [3H]arginine and treated these bacteria with a lipid-soluble, active-site-directed chloromethyl ketone inactivator of pancreatic and granulocyte elastases (carbobenzoxy-L-glycyl-L-leucyl-L-alanine chloromethyl ketone, dissolved in methanol). Control bacteria were treated with methanol alone. When E. coli pretreated with the inactivator were incubated with solutions of porcine pancreatic elastase or with PMN granule extract, release of trichloroacetic acid-soluble radioactivity was significantly lower than in the control E. coli. Similar results were obtained when treated and control E. coli were fed to viable human PMN. In contrast, release of trichloroacetic acid-soluble radioactivity from E. coli containing [3H]thymidine was not affected by pretreatment of bacteria with elastase inactivator before feeding them to PMN, suggesting that phagocytosis of E. coli had not been inhibited by the chloromethyl ketone. When treated and control bacteria were fed to PMN, no significant difference was observed in the activity of lysosomal beta-glucuronidase recovered from post-granule supernatant fractions of homogenized leukocytes, suggesting that lysosomal degranulation had not been suppressed by the inactivator. However, elastase activity of the same fractions was depressed if the leukocytes had phagocytized chloromethyl ketone-treated E. coli, suggesting that inhibition of PMN elastase had occurred. We conclude that PMN elastase participates in digestion of E. coli proteins by human PMN.

Extracellular and bacterial factors influencing staphylococcal phagocytosis and killing by human polymorphonuclear leukocytes

Extracellular and bacterial factors that influence the phagocytosis and killing of staphylococci by human polymorphonuclear leukocytes have been studied. Staphylococcus epidermidis strains were, in general, more rapidly phagocytized than were S. aureus strains. However, two strains of S. epidermidis had a very slow rate of ingestion. Although the rate of phagocytosis of S. aureus Wood 46 was greater than that of S. aureus 502A, the Wood 46 strain was more difficult to kill. Serum was essential for phagocytosis of both S. aureus and S. epidermidis. The opsonic titer of pooled serum was similar for S. aureus and S. epidermidis. In normal pooled serum, heat-labile factors were more important for effective phagocytosis than they were in immune serum. Although a saturation point for ingestion was reached, the percentage of ingested bacteria that remained alive within the leukocyte remained relatively fixed. Heat-killed and live staphylococci were igested in a similar fashion. The rate of phagocytosis was greatly reduced at 41 degrees C.

Studies on phagocytosis in fish. I. In vitro uptake and killing of living Staphylococcus aureus by peripheral leucocytes of carp (Cyprinus carpio)

The clearance and uptake of Staphylococcus aureus were studied in vitro in whole blood of immunized and non-immunized carp. Bacterial numbers were determined by : (1) counting viable cells in agar plates; (2) counting radioactivity of 14C-labelled bacteria. Similar results were obtained by these two methods. Neither the bacterial growth nor the ingestion of bacteria into the cells seem to be influences by immunization. In both immunized and non-immunized groups the number of intracellular bacteria increased rapidly during the first 120 minutes, then progressed at a slow rate during the next 60 minutes, after which there was a rapid decrease in the number of bacteria only in the immune blood. It is concluded that the phagocytic cells of immune blood are more effective in activating or killing bacteria.

NADPH oxidase deficiency in X-linked chronic granulomatous disease

We measured the cyanide-insensitive pyridine nucleotide oxidase activity of fractionated resting and phagocytic neutrophils from 11 normal donors, 1 patient with hereditary deficiency of myeloperoxidase, and 7 patients with X-linked chronic granulomatous disease (CGD). When measured under optimal conditions (at pH 5.5 and in the presence of 0.5 mM Mn++), NADPH oxidase activity increased fourfold with phagocytosis and was six-fold higher than with NADH. Phagocytic neutrophils from patients with CGD were markedly deficient in NADPH oxidase activity.

Current concepts of the mechanism of acute inflammation in gouty arthritis

The acute gouty attack develops after free crystalline monosodium urate crystals appear in the joint cavity (1). Recent developments in the investigation of urate crystal-induced inflammation have led to a better understanding of the pathogenesis of acute gouty arthritis. The purpose of this review is to summarize present concepts concerning the mechanism of the acute gouty attack.

The effect of 3',5'-adenosine monophosphate on granulocyte adhesion

Human granulocyte adhesion to glass capillary tubes was tested in the presence of agents that increase intracellular levels of cyclic 3',5'-adenosine monophosphate (cAMP). Adhesion was significantly reduced by 10(-3)-10(-4) M dibutyryl cAMP, 10(-4)-10(-6) M prostaglandin E(1) (PGE(1)), 10(-4)-10(-6) M histamine, or 10(-3) M theophylline. Adhesion was not suppressed by 10(-4) M theophylline unless it was combined with PGE(1) or histamine. Eosinophil and basophil adhesion was especially sensitive to suppression by the above agents. These findings suggest that intracellular cAMP may play a role in regulation of adhesiveness of human basophils, eosinophils, and neutrophils.

Effect of experimental pneumococcal meningitis on respiration and circulation in the rabbit

Pathophysiological studies in bacterial meningitis in man have been limited by clinical variability and the necessity for immediate therapy. After the development of a reliable animal model of pneumococcal meningitis, we studied respiration and circulation in 25 anesthetized New Zealand white rabbits during untreated pneumococcal meningitis and in 33 healthy controls. In meningitis, we found increased lactic acid in cerebrospinal fluid (CSF). Increased ventilation, perhaps due to CSF lactic acid accumulation, resulted in respiratory alkalosis; the concomitant lowering of Pco(2) acted as a homeostatic mechanism to restore pH toward normality in the CSF. Hyperventilation increased with the duration of the illness. Cardiac output was also increased with decreased peripheral vascular resistance but with only slight reduction in mean systemic and pulmonary arterial pressures. In the final hour of life, peripheral vascular resistance fell further; ventilation declined and then abruptly ceased while cardiac activity continued. Lactic acid accumulation in the CSF, found in both experimental and human pneumococcal meningitis, may cause the hyperventilation found in this disease and may contribute to death.

Segmental response of the macrophage plasma membrane to a phagocytic stimulus

A method of attaching mouse RBCs to mouse macrophages is described. Both cell types were coated with rabbit anti-mouse macrophage F(ab')(2), and cross-linkage of cells was effected with sheep F(ab')(2) directed against rabbit F(ab')(2). 98% of macrophages attached an average of 11 RBCs each. Attachment occurred at 37 degrees C and was stable for at least 4 h. Less than 0.1% of macrophages ingested RBCs under these conditions. Latex particles and opsonized pneumococci were ingested as avidly by RBC-coated macrophages as by native macrophages. Ingestion of these particles did not prompt ingestion of attached RBCs. When anti-RBC IgG was added, however, over 90% of macrophages ingested an average of six RBCs each. Thus, ingestion of one particle does not trigger generalized phagocytosis of all particles attached to the cell's plasma membrane, and the phagocytic stimulus is confined to the segment of the cell's plasma membrane immediately adjacent to the particle being ingested.

Sequential degranulation of the two types of polymorphonuclear leukocyte granules during phagocytosis of microorganisms

The sequential discharge of neutrophilic polymorphonuclear leukocyte (PMN) granules-azurophils and specifics-was investigated by electron microscopy and cytochemistry. Thus the enzyme content of PMN phagocytic vacuoles was determined at brief intervals after phagocytosis of bacteria, utilizing peroxidase as a marker enzyme for azurophil granules, and alkaline phosphatase for specifics. At 30 s, approximately half the phagocytic vacuoles were reactive for alkaline phosphatase, whereas none contained peroxidase. Peroxidase-containing vacuoles were rarely seen at 1 min, but by 3 min, vacuoles containing both enzymes were consistently present. Alkaline phosphatase was found in both small and large vacuoles, whereas peroxidase was visible only in large ones. By 10 min, very big phagocytic vacuoles containing considerable amounts of reaction product for both enzymes were evident. These observations indicate that the two types of PMN granules discharge in a sequential manner, specific granules fusing with the vacuole before azurophils. In an earlier paper, we reported that the pH of phagocytic vacuoles drops to 6.5 within 3 min and to approximately 4 within 7-15 min. Substances known to be present in specific granules (alkaline phosphatase, lysozyme, and lactoferrin) function best at neutral or alkaline pH, whereas most of those contained in azurophil granules (i.e., peroxidase and the lysosomal enzymes) have pH optima in the acid range. Hence the sequence of granule discharge roughly parallels the change in pH, thereby providing optimal conditions for coordinated activity of granule contents.

Effect of sodium polyanetholesulfonate on antimicrobial systems in blood

Sodium polyanetholesulfonate (SPS), an anticoagulant which inhibits the antimicrobial systems of blood, is used widely in blood culture media. The addition of SPS to experimental blood cultures inoculated with small numbers of a variety of organisms caused a striking increase in recovery of these organisms. Sodium fluoride also increased the incidence of positive blood cultures with some organisms. SPS completely inhibited serum antibacterial activity and serum-dependent phagocytosis (and killing) by isolated leukocytes at a concentration usually employed in blood culture media. SPS also stimulated both glucose C-1 oxidation in resting leukocytes and formate oxidation in both resting and phagocytosing leukocytes in serum-free systems. These in vitro studies support the concept that SPS is a useful additive to blood culture media and further elaborate on the mechanism of its inhibition of the microbicidal activity of blood.

Cytochalasin B: inhibition of D-2-deoxyglucose transport into leukocytes and fibroblasts

Cytochalasin B inhibits transport of (D)-2-deoxyglucose and of glucosamine into kukocytes, but does not impair uptake of kucine by these cells. This inhibitory action is rapid and reversible, and results in suppression of glycolysis. Cytochalasin B also blocks transport of (D)-2-deoxyglucose, but not of leucine, into mouse L strain fibroblasts.

A method of separating the lymph-node cells, of C57 BL mice allergized with BP8 ascites tumour, into two fractions with a fast and slow electrophoretic mobility: demonstration that only the "fast LNC" will protect C3H mice against challenge with the tumour

Lymph-node cells (LNC) from C57 Bl mice, allergized with BP8 ascites tumour, were separated in vitro into 2 populations on the basis of the charge on their plasma membranes. The population with a lower electrophoretic mobility (“slow LNC”) were agglutinated at zero zeta potential by a critical dose of poly-l-lysine leaving the “fast LNC” in suspension. Only the “fast LNC” protected C3H mice against fatal challenge with BP8 tumour in vivo.

The role of phagocyte function in resistance to infection

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Phagocytosis of platelets by leukocytes in artificial thrombi and in platelet aggregates induced by adenosine diphosphate

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Respiration and glucose oxidation in human and guinea pig leukocytes: comparative studies

A comparison has been made of the metabolic shifts in human and guinea pig leukocytes when they phagocytize. Respiration of guinea pig polymorphonuclear leukocytes (PMN) and the increment during phagocytosis were each about 2(1/2)-fold that of human PMN. This was also true of the direct oxidation of glucose-6-P (hexose monophosphate shunt). Enzymes potentially responsible for these phenomena have been compared in each species. Cyanide-insensitive NADH oxidase and NADPH oxidase were measured and only the formed exhibited adequate activity to account for the respiratory stimulus durintg phagocytosis. The hydrogen peroxide formed by this enzyme stimulates the hexose monophosphate shunt by oxidizing glutathione which upon reduction by an NADPH-linked glutathione reductase provides NADP to drive the hexose monophosphate shunt. Other linkages between respiratory stimulation and that of the hexose monophosphate shunt also pertain in the guinea pig.