Functional and metabolic properties of polymorphonuclear leucocytes. II. The influence of a lipopolysaccharide endotoxin

Cerebrospinal fluid lactic acidosis in bacterial meningitis

A rapid, microenzymatic method was used to measure cerebrospinal fluid lactate levels in 205 children with suspected bacterial meningitis. Fifty children with normal CSF containing fewer than 0.005 X 10(9)/l WBC, no segmented neutrophils, glucose 3.4 +/- 0.8 mmol/l (61.2 +/- 14.4 mg/100 ml), and a protein of less than 0.30 g/l had CSF lactate levels below 2.0 mmol/l (18 mg/100 ml) (mean and standard deviation 1.3 +/- 0.3 mmol/l (11.8 +/- 2.7 mg/100 ml)). In 31 cases of proved viral meningitis as with 58 cases of clinically diagnosed viral meningitis, levels were below 3.8 mmol/l (34.5 mg/100 ml), being 2.3 +/- 0.6 mmol/l (20.9 +/- 5.4 mg/100 ml), and 2.1 +/- 0.7 mmol/l (19.1 +/- 6.4 mg/100 ml) respectively. Sixty-six cases of bacterial meningitis had CSF lactate levels ranging from 3.9 mmol/l (35.4 mg/100 ml) to greater than 10.0 mmol/l (90.0 mg/100 ml). Longitudinal studies in 7 children with bacterial meningitis showed that cerebrospinal fluid lactate levels differentiated bacterial from viral meningitis up to 4 days after starting treatment with antibiotics. Use of CSF lactate measurement for monitoring the efficacy of treatment is illustrated in a case of bacterial meningitis due to Pseudomonas aeruginosa. The origin of the cerebrospinal fluid lactate acidosis and the role of lactate in the pathophysiological cycle leading to intensification of brain tissue hypoxia and cellular damage is discussed with respect to the short-term prognosis and the long-term neurological sequelae.

Chemotactic substances in the treatment of experimental intraperitoneal infections

Since peritonitis remains a serious clinical problem, we have evaluated the prophylactic efficacy of intraperitoneally administered chemotactic substances in murine intraperitoneal infections. The injection of 10 ml of 3% thioglycollate increased the peritoneal white blood cell count of rats from 1.3 +/- 0.1 X 10(6) (mean +/- SEM) to 1.1 +/- 0.1 X 10(7) (mean +/- SEM) cells/ml. This increase in the number of intraperitoneal phagocytes resulted in reduction in mortality caused by an inoculum consisting of E. coli and hemoglobin from 68% in the control group to 29% in the thioglycollate pretreated group (p less than or equal to 0.02). Intraperitoneal injection of N-formyl-methionyl-phenylalanine (FMP), a chemotactically active oligopeptide, increased the intraperitoneal granulocyte count from virtually 0 to 1 X 1.9 +/- 0.53 X 10(4) (mean +/- SEM) cells/ml after 90 minutes. The rats pretreated in such a manner showed a mortality of 51% after an intraperitoneal challenge with an E. coli/hemoglobin inoculum as compared to a mortality of 72% in control animals (p less than or equal to 0.025). Thus, chemotactic substances can effectively increase the number of phagocytes and concurrently induce resistance to an intraperitoneal bacterial challenge.

[Oxygen-dependent influence of lipopolysaccharide endotoxin on polymorphonuclear leukocytes (author's transl)]

In in vitro experiments the effect of bacterial endotoxin (Lipopolysaccharide E. coli O 26 :B 6) on the ingestion, NBT reduction, and the formation of cytoplasmic vacuoles of polymorphonuclear leukocytes in the atmosphere of 21 vol-% O2 and 99.9 vol-% N2, respectively, was tested. High concentrations of endotoxin in O2-atmosphere cause an inhibition of the functions and a stimulation of vacuole formation, N2 atmosphere shows these effects of endotoxin on the ingestion and vacuole formation, if at all, in a lesser degree. These results show that endotoxin in high concentrations possibly causes an auto-oxidation of the polymorphonuclear leukocytes. This interpretation of the results is in accord with findings of other authors.

A neutrophil disorder induced by capnocytophaga, a dental micro-organism

We recovered capnocytophaga, a gram-negative anaerobe implicated in the pathogenesis of periodontal disease, from two patients with a history of dental infections. Neutrophils from both patients failed to acquire the asymmetric shape characteristic of normal neutrophils. Fluorescein staining of the patients' living neutrophils remained diffuse and patchy instead of showing the normal pattern in which the fluorescence is swept into the rear of the cell. The locomotion of one patient's neutrophils in vitro was less than 50 per cent of that of normal neutrophils, and migration of this patient's neutrophils into dermal abrasions was reduced, although phagocytosis and nitroblue tetrazolium reduction were normal. All abnormalities of neutrophil morphology and function disappeared after eradication of the capnocytophaga infections. Sonicates and culture medium of capnocytophaga contained a dialyzable substance that caused normal neutrophils to behave like neutrophils obtained from the infected patients.

Endotoxin in vitro interactions with human neutrophils: depression of chemiluminescence, oxygen consumption, superoxide production, and killing

Endotoxin was shown to depress neutrophil bactericidal activity while enhancing Nitro Blue Tetrazolium reduction and hexose monophosphate shunt activity. Separation of bactericidal action from oxidative metabolism suggests that the effect of endotoxin might involve the formation of reactive oxygen radicals such as superoxide. Chemiluminescence often accompanies metabolic activation of polymorphonuclear neutrophils (PMNs). However, human PMNs did not show chemiluminescence when challenged with endotoxin (lipopolysaccharide; LPS) or lipid A. Superoxide formation was also unaffected by endotoxin. In contrast, preincubation of PMNs with LPS for 30 min produced significant depression of chemiluminescence, oxygen consumption, and superoxide formation. Decreased chemiluminescence was not the result of complement consumption. In a cell-free system, superoxide was not scavenged by LPS, nor did LPS stimulate superoxide dismutase. Oxidase enzymes for reduced nicotinamide adenine dinucleotide or reduced nicotinamide adenine dinucleotide phosphate harvested from broken cells were not affected by LPS. The toxicity of LPS may reside in its ability to activate the PMNs while simultaneously blocking bactericidal capacity.

Strain-dependent cytotoxic effects of endotoxin for mouse peritoneal macrophages

The cytotoxic effects of bacterial lipopolysaccharides (LPS) on mouse leukocytes have been examined in vivo and in vitro. Intraperitoneal injection of LPS into C57BL/6 mice greatly reduced the recovery of mononuclear cells; LPS was cytotoxic for macrophages, but had a mitogenic effect on lymphocytes. Similar effects of LPS on peritoneal leukocytes were observed in vitro. When monolayers of adherent peritoneal cells were studied in vitro, cytotoxicity was also observed, suggesting that the effect of LPS on macrophages is direct and does not require participation by lymphocytes. Entirely different results were obtained when peritoneal macrophages from LPS-resistant C3H/HeJ mice were studied. LPS failed to activate lymphocytes and was not cytotoxic for macrophages in vitro or in vivo. The effect of LPS on polymorphonuclear leukocytes appeared to be the same in all mouse stains studied. Lipid A was shown to be the most biologically active portion of the LPS molecule. Whereas polysaccharide-deficient endotoxins extracted from rough mutants of Salmonella typhimurium were cytotoxic for macrophages in vitro, polysaccharides that lacked esterified fatty acids did not exhibit this activity. Since LPS may mediate its effects through affinity for mammalian cell membranes, the cellular unresponsiveness of C3H/H3J mice to LPS may reflect an inability of cells from LPS-resistant strains to interact with LPS at the membrane level.

Gas liquid chromatography in the rapid diagnosis of meningitis

Gas liquid chromatography was employed to detect lactic acid in the cerebrospinal fluid of patients suspected of having bacterial meningitis. The technique was found to be both rapid and reliable. Differentiation between aseptic, purulent, and partially treated bacterial meningitis was readily achieved. The effectiveness of therapy in bacterial meningitis was indicated by a rapid fall in the concentration of lactic acid.

Neutrophil function in cured cancer patients

Spontaneous and endotoxin-stimulated nitroblue tetrazolium (NBT) dye reduction was evaluated in 86 individuals cured of various types of solid malignancies and in 55 healthy adults. Oxygen consumption tests, at rest and during phagocytosis, were performed with polymorphonuclear leukocytes of 22 patients and 10 controls, chosen at random. The results revealed an impaired capacity of patients' neutrophils to reduce NBT. The decrease in the stimulated reduction values was more pronounced (p less than 0.0005) than in spontaneous values (p less than 0.01), and was also noticed in patients who had been treated by surgery alone and in those with a disease-free interval of 10 years or more. Oxygen consumption by patients' leukocytes was similar to that of controls. The present results, especially those of the endotoxin-stimulated NBT test, might reflect a neutrophil dysfunction in cured cancer patients. The nature of such an abnormality and its possible clinical implication are still obscure.

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.

Membrane changes in human platelets induced by lipopolysaccharide endotoxin

The unexplained occurrence of thrombocytopenia in cases of Gramnegative sepsis in man led us, in the light of animal experiments indicating the blood platelet as the target cell for endotoxin, to examine the effect of Salmonella enteritidis lipopolysaccharide B on human platelets. Human platelets were separated from a coat of plasma proteins by Sepharose 2B filtration or by a combined procedure of albumin gradient and Sepharose 2B filtration. The action of endotoxin on human platelets resulted in membrane changes manifested by dose-dependent release of [3H]serotonin and adenine nucleotides. Cytoplasmic marker, lactic dehydrogenase, and lysosomal marker, beta glucuronidase, were retained indicating that the release reaction was selective. Release of [3H]serotonin was specific for endotoxin since other particulates, zymosan and erythrocyte stroma, were without effect. Endotoxin, added to gel-filtered human platelets, induced a significant evolution of platelet factor 3 procoagulant activity. Preincubation of endotoxin with a membrane-rich homogenate of human platelets inhibited its labilizing effect on human platelets thus suggesting an interaction between endotoxin and the platelet membrane itself. Other plausible factors in this interaction [fibrinogen, adenine nucleotides, thrombin, sialic acid residues, and IgG] were eliminated on the basis of a series of control experiments. From the negligible effect of aspirin and indomethacin, we may infer that the interaction of endotoxin with platelets does not depend on the platelet prostaglandin synthesis pathway. The direct interaction of endotoxin with the human platelet membrane comprises a new mechanism which may help to clarify the pathogenesis of vascular and haemostatic disorders accompanying bloodstream infections due to Gram-negative bacteria.

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.

Induction of macrophage plasminogen activator by endotoxin stimulation and phagocytosis: evidence for a two-stage process

The injection of thioglycollate medium into the peritoneal cavity of the mouse induces high levels of macrophage fibrinolytic activity due to the production and secretion of a plasminogen activator, a trypsinlike serine protease, which is absent in unstimulated macrophages. Intraperitoneal injection of endotoxin or mineral oil can stimulate only a fraction (<10%) of the fibrinolytic activity of thioglycollate cells, similar to the partial stimulation (<10%) seen 1-2 days after phagocytosis of latex or SRBC by unstimulated macrophages. The endotoxin-stimulated macrophages contain and release relatively low levels of plasminogen activator, but these primed cells can be triggered to produce and secrete high levels of enzyme, by phagocytosis of latex. Under conditions where the plasminogen activator is induced and secreted, there are no effects on the production and/or release of lysozyme or intracellular acid hydrolases, Discovery of a two-stage procedure for inducing macrophage plasminogen activator made it possible to study the role of cell priming and phagocytosis separately. Endotoxin was a more effective priming agent, weight for weight, than lipid A:BSA complex. Secretion of the plasminogen activator was induced only by thioglycollate, or endotoxin and latex. In situ fibrinolysis was induced by these agents and mineral oil, BCG, and fetal calf serum, in decreasing order of effectiveness. Phagocytosis of latex in all cases except thioglycollate stimulation, increased fibrinolytic activity from three- to sixfold. Latex and a variety of other particles such as M. lysodeikticus, aggregated gamma-globulin and immune complexes showed dose-dependent stimulation of fibrinolysis by endotoxin-primed macrophages. Although the initial phagocytic trigger was not specific for the substance employed, the ability to induce a sustained response depended on the persistence of the phagocytized particle within the cell. Fibrinolysis and secretion of plasminogen activator continued at high levels for at least 9 days after uptake of latex, a nondigestible particle, whereas plasminogen activator was secreted only transiently after ingestion of rapidly digested M. lysodeikticus. The induction of plasminogen activator secretion provides a mechanism by which the activated macrophage can exert a selective effect on its extracellular environment.

Effects of phorbol myristate acetate on the metabolism and ultrastructure of neutrophils in chronic granulomatous disease

Previous investigations have demonstrated that phorbol myristate acetate (PMA), the active principle of croton oil, stimulates alterations in normal polymorphonuclear leukocytes (PMN) that resemble closely the changes that develop in the cells after phagocytosis of bacteria. The present study has compared the effects of PMA and heat-killed bacteria on the oxygen uptake, glucose oxidation, nitroblue tetrazolium (NBT) reduction, and ultrastructure of normal neutrophils and PMN from six patients with chronic granulomatous disease (CGD). PMA stimulated oxygen consumption, hexose monophosphate shunt activity, and NBT reduction in normal cells but failed to produce similar effects in CGD neutrophils. However, PMA did induce formation of cytoplasmic vacuoles in the CGD cells similar to those observed in normal neutrophils. The results indicate that PMA is a useful nonparticulate agent for distinguishing between normal and CGD neutrophils and for studying basic mechanisms of phagocytosis in normal and abnormal PMN.

Hyperactivity of neutrophil leukotactic responses during active bacterial infection

To determine if changes in neutrophil leukocyte function occur during active bacterial infection, the neutrophils of 25 patients with active bacterial infection and 25 age-matched controls were compared for leukotactic activity, random mobility, and nitroblue tetrazolium reduction. The neutrophil leukocytes of patients with bacterial infection were hyperactive in unidirectional movement toward a chemotactic stimulus as measured in the leukotactic assay and usually had increased nitroblue tetrazolium reduction. The mean leukotactic index was 165+/-56 in patients with bacterial infection and 70+/-11 in controls (P < 0.001). After 7-10 days of appropriate therapy with clinical and bacteriological response, leukotactic activity returned to normal values. A hyperactive leukotactic response continued, however, in patients with persisting bacterial infection. The hyperactive leukotactic response of circulating neutrophils appears to be an early and sensitive event in the inflammatory cycle stimulated by bacterial infection and may aid in the localization of invading bacteria.

Stimulation of heme oxygenase in macrophages and liver by endotoxin

In rat peritoneal macrophages, engaged in erythrophagocytosis in vitro, endotoxin stimulated heme oxygenase (HO) activity, which was additive to the substrate-mediated enzyme induction produced by the ingested erythrocyte hemoglobin. Endotoxin neither appeared to injure the erythrocytes, nor did it enhance the rate of erythrophagocytosis. In intact rats, HO activity in both parenchymal and sinusoidal cells of the liver was increased after treatment with endotoxin. It is likely that endotoxin directly stimulates HO activity, a process which may account for the reported rise in bilirubin formation in endotoxin-treated animals. The effect of endotoxin on HO may represent part of the general activation of phagocytic cells by endotoxin.

The depression of phagocytosis by exogenous cyclic nucleotides, prostaglandins, and theophylline

The effects of agents that elevate intracellular cyclic adenosine 3',5'-monophosphate (cAMP) have been studied with respect to phagocytosis by guinea pig polymorphonuclear leukocytes. The investigation depends upon the use of a precise method for following ingestion. Theophylline, dibutyryl cAMP, and prostaglandins inhibited the phagocytosis of starch particles. The inhibitions caused by prostaglandins E(1), E(2), and F(2alpha) (PGE(1), PGE(2), and PGF(2alpha)) were synergistic with that due to theophylline. Inhibition by PGA(1) and PGA(2) was not. At equal concentrations the order of increasing inhibition of phagocytosis (assayed at 10 min) by the prostaglandins was PGE(1) < PGF(2alpha) < PGE(2) < PGA(1) = PGA(2). Our results are consistent with the hypothesis that increased intracellular levels of cAMP impair the phagocyte's ability to ingest particles. The mechanism of the inhibition has not been defined. The increment in oxidation of [1-(14)C]glucose to (14)CO(2) that normally accompanies phagocytosis was found to be depressed in the presence of PGE(1) or theophylline, together or individually as expected from the inhibition of phagocytosis. Paradoxically, oxygen consumption although depressed by theophylline or PGE(1) plus theophylline, was stimulated by PGE(1) alone.

A neutrophil-immobilizing factor derived from human leukocytes. I. Generation and partial characterization

A factor has been derived from human leukocytes which irreversibly inhibits the response of human neutrophils to diverse chemotactic stimuli without impairing their viability. It is released by both polymorphonuclear and mononuclear leukocytes during incubation in acidic medium, after endotoxin exposure and subsequent incubation in low potassium medium, and during phagocytosis of particles. It is extractable from both leukocyte types and therefore must be preformed. This chemotactic inhibitor is completely separable from contaminating chemotactic activity in the crude supernatants, has a mol wt of 5000, and is inactivated by digestion with trypsin or chymotrypsin. It has been termed a neutrophil-immobilizing factor because it inhibits neutrophils directly and independently of the chemotactic stimulus, and has relatively little effect on human monocyte chemotaxis.

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.

The dissociation by colchicine of phagocytosis from increased oxygen consumption in human leukocytes

The effect of colchicine on the uptake of oxygen by human leukocytes during phagocytosis of live streptococci or of killed staphylococci was compared with the effect of colchicine on phagocytosis per se, measured in a sensitive bacterial system. The increase in oxygen consumption that normally accompanies phagocytosis was consistently diminished in leukocytes incubated with colchicine in concentrations as low as 2.5 x 10(-6) mole per L (1 mug per ml), and this inhibition was dosage dependent. Yet there was no evidence of decreased phagocytosis with concentrations of colchicine as high as 2.5 x 10(-4) mole per L (100 mug per ml). Furthermore, with measurements at 20, 40, and 60 minutes, the rate of phagocytosis was comparable with and without colchicine.A clue to the dissociation between oxygen consumption and phagocytosis was found in rapidly dried preparations of the incubated leukocytes. Ingested bacteria were present in both control and colchicine-treated granulocytes. In addition, control cells showed normal loss of granules (lysosomal particles) and prominent cytoplasmic vacuoles (digestive vacuoles). Colchicine-treated cells, however, showed less such degranulation and vacuolization. Measurements of granule-associated acid phosphatase activity after phagocytosis support the morphologic observations of less degranulation in colchicine-treated leukocytes. The muted metabolic and morpholgic response to phagocytosis in colchicine-treated cells may be important for the anti-inflammatory effect of colchicine in acute gouty arthritis. Colchicine may also find wider use in defining structure-function dependencies in metabolically stimulated cells.

Metabolic and morphological observations on the effect of surface-active agents of leukocytes

Morphological and metabolic observations have been made on the effects of endotoxin, deoxycholate, and digitonin (at less than 50 microg/ml) on polymorphonuclear leukocytes and mononuclear cells. The agents stimulate the respiration and glucose oxidation of these cells in a manner similar to that seen during phagocytosis. Electron microscopy revealed no morphological changes with the first two agents, but dramatic membrane changes were seen in the case of digitonin. Here tubular projections of characteristic size and shape formed on and split off the membrane. All the agents stimulated uptake of inulin, but efforts to demonstrate increased pinocytosis by electron microscopy have not so far succeeded, probably due to limitations in present experimental techniques.

Mechanisms of antibacterial action in the respiratory system

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The Effect of Bacterial Endotoxin on the Placenta of the Rat

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