Chemiluminescence Response Of Monocytes Research Articles

Cross-talk between human monocytes and cancer cells during reactive oxygen intermediates generation: the essential role of hyaluronan.

Human monocytes exhibit considerable cytocidal activity against tumor (but not normal cells) associated, at least partly, with the generation of reactive oxygen intermediates (ROIs). The present study examined the role of surface determinants and hyaluronan (HA) in the induction of ROI production by human monocytes stimulated with cancer cells, as measured by luminol-enhanced chemiluminescence (CL). The inhibitory effect of monoclonal antibodies (MAbs) indicated the engagement of CD18, CD29 and CD44 adhesion molecules. Preincubation of monocytes and tumor cells, expressing CD44 determinants, with either anti-CD44 MAb or HA inhibited CL generation. Addition of HA to monocytes decreased the expression of CD44 and induced CL response. Supernatants from the cultures of tumor cells stimulated CL response of monocytes, an effect that was abolished by treatment of the supernatants with hyaluronidase (HAase) or by preincubation of monocytes with an anti-CD44 MAb. These results indicate that several surface molecules of monocytes, including CD44, are required to trigger the generation of ROI after their contact with tumor cells, whereas HA overexpressed on some cancer cells may allow monocytes (via CD44) to distinguish between transformed and normal cells. However, blocking of CD44 on monocytes by free HA dampens their response to tumor cells. Taken together, these observations suggest that the presence of HA in the tumor stroma may modulate effector functions of infiltrating macrophages and their interactions with cancer cells in situ.

Proinflammatory activation of neutrophils and monocytes by Helicobacter pylori is not associated with cagA, vacA or picB genotypes

Chronic Helicobacter pylori infection is associated with mucosal inflammation. The aim of the present study was to assess human neutrophil and monocyte activation induced by H. pylori strains with different virulence genotypes. Bacterial sonicates from 12 strains were used to induce phagocyte up-regulation of adherence molecule CD11b, assessed by fluorescence flow cytometry, and oxidative burst responses, assessed by chemiluminescence. A dose-dependent induction of the expression of CD11b was observed with sonicate from all H. pylori strains on both neutrophils and monocytes. Strains negative for cagA and picB genes had the same inducing activity of upregulation of CD11b as strains positive for these genes. A vacA-S2 type strain had the same activity as vacA-S1 type strains. The induction of toxic oxygen radicals by H. pylori-activated neutrophils gave higher median values for the cagA-positive strains than for the cagA-negative strains. For the monocyte chemiluminescence response, cagA-negative strains gave higher median values compared to cagA-positive strains. We conclude that upregulation of the neutrophil and monocyte adherence molecule CD11b induced by H. pylori sonicates is not associated with the presence of cagA, picB or mosaic pattern of vacA, and that cagA, picB-negative strains and vacA-S2 strains retain their inflammatory capacity.

Inhibition of the monocyte chemiluminescent response to anti-D-sensitized red cells by Fc gamma RI-blocking antibodies which ameliorate the severity of haemolytic disease of the newborn.

Luminol-enhanced chemiluminescence (CL) may be used to measure the metabolic response of human monocytes to red cells sensitized by anti-D. The functional activity of maternal anti-D when measured in this way correlates with the severity of haemolytic disease of the newborn (HDN) in D-positive fetuses. Occasionally, however, women with levels of functionally active anti-D predictive of moderate to severe HDN may deliver D-positive babies with unexpectedly mild disease. In the current study we have shown that serum from 12 of 15 such women contained monocyte-binding IgG antibodies which blocked Fc gamma RI and inhibited the CL response of monocytes to red cells sensitized with monoclonal anti-D. In contrast, Fc gamma RI-blocking antibodies were found in the serum from only 4 of 11 women who were matched for anti-D activity but who delivered babies with severe HDN (p < 0.05). Antibodies responsible for inhibition of CL responses were predominantly against HLA class I antigens. The CL response of monocytes to sensitized red cells was at least as sensitive to inhibition by Fc gamma RI-blocking antibodies as were phagocytic and lytic responses. Our data suggest that inhibition of the CL test is an objective, sensitive and relatively simple technique for detecting and investigating Fc gamma RI-blocking antibodies which may ameliorate the severity of HDN.

Modulation of the counts and functions of neutrophils and monocytes under in vivo hyperthermia conditions.

The present work was designed to examine the effect of in vivo hyperthermia on the cell number and functions of polymorphonuclear leucocytes (PMN) and monocytes in human beings. Eight healthy volunteers were immersed into a waterbath (WI) (water temperature 39.5 degrees C) for 2 h, whereby their rectal temperature rose to 39.5 degrees C. On a later day they served as their own controls, being immersed into thermoneutral water (34.5 degrees C) for 2 h. Blood samples were collected before immersion, at body temperatures of 38, 39 and 39.5 degrees C as well as 2 h after water immersion. The neutrophil count was significantly increased at 39.5 degrees C, as well as 2 h after hot WI, compared with control. The monocyte count was significantly augmented at 38 and 39 degrees C and 2 h after hyperthermic load. The FMLP-induced chemiluminescence response, for a given number of PMN, was significantly reduced 2 h after hot WI. The total amount (per litre of blood) of superoxide production by PMN stimulated with opsonized zymosan (OZ) was significantly augmented at 39 and 39.5 degrees C and 2 h after WI. In vivo hyperthermia did not affect the function of monocytes, but when correlated to the changes in the concentrations of monocytes (response per litre blood) a significant increase in the phorbol myristate acetate (PMA)- and OZ-enhanced superoxide production occurred at 38 and 39 degrees C, as well as 2 h after termination of hot WI. Furthermore the OZ-enhanced monocyte chemiluminescence response per litre of blood was significantly enhanced 2 h after hot WI.(ABSTRACT TRUNCATED AT 250 WORDS)

Activation of human monocyte chemiluminescence response by acylpoly(1,3)galactosides derived from Klebsiella pneumoniae.

The stimulating activity of several preparations isolated from a membrane proteoglycan of a nonencapsulated smooth strain of Klebsiella pneumoniae (Kp-MPG) on the oxidative burst of human blood monocytes was assessed by luminol-enhanced chemiluminescence (CL). Five Kp derivatives were studied: a 34-kd acylpoly(1,3)galactoside (APG), obtained by drastic alkaline hydrolysis and purified by chromatography; an APG preparation subjected to acid hydrolysis that removed the core part and all fatty acids, leaving intact the galactose chain of APG (GC-APG); an APG preparation subjected to mild oxidation (ox APG); a preparation obtained by mild alkaline hydrolysis of Kp-MPG, containing additional ester-linked C14 and C16 fatty acids bound to the APG molecule (EFA-APG); and a polymer of the latter compound, APG pol. EFA-APG directly stimulated monocyte CL, whereas Kp-MPG, APG pol, and the whole bacterial cells had little or no activity. APG itself and ox APG induced a weaker response than EFA-APG. Polymyxin B sulfate completely inhibited the CL response to bacterial lipopolysaccharide (LPS) but not to EFA-APG. The stimulating action of EFA-APG on blood monocytes was dependent on the extracellular levels of both calcium and magnesium. Preincubation of monocytes with monoclonal antibody anti-Mac-1 directed against CD11b, the alpha chain of complement receptor type 3 (CR3; CD11b/CD18), strongly inhibited CL activation by EFA-APG and to a lesser extent CL activation by unopsonized zymosan and rough LPS. Altogether, these findings provide indirect evidence for the contribution of the CD11b/CD18 integrin in the functional interaction of EFA-APG with monocyte membranes. They demonstrate the role of fatty acids in the triggering of monocyte oxidative burst, while the polysaccharide chain itself does not contribute to induction of the CL response in this model. In keeping with the effects of EFA-APG and APG, we show that the monocyte CL response was triggered by bacterial LPS from the rough strain of Salmonella minnesota Re 595 and its lipid A, but not by LPS from smooth strains, again suggesting a critical role for the lipid moiety.

Stimulating effect of E.coli L-form cytoplasmic membranes on the macrophage functions of influenza virus infected mice

To evaluate their defense level against bacterial infection of patients with liver cirrhosis, we compared the luminol-dependent chemiluminescence (CL) response of peripheral blood from 40 patients with that from 40 healthy volunteers. Small quantities of heparinized whole blood (100 μl; final dilution, 1:10) were used for phagocytes, and CL was measured on addition of nonopsonized zymosan or Escherichia coli without special opsonization. Whole blood CL in cirrhotic patients was significantly lower than that in the healthy controls. The incidence of lower CL response in patients increased as disease stage advanced. Polymorphonuclear leukocytes (PMN) from cirrhotic patients exibited a slightly lower CL response than those from controls, but this was not statistically significant. In contrast, the CL response of monocytes in patients was significantly lower than that of controls. The opsonizing capacity of the patients’ sera and ascitic fluid was also decreased. In fact, the levels of opsonins such as complement in the patients’ sera and both immunoglobulins and complement in the ascitic fluids were found to be lower in cirrhotic patients. On the basis of these findings, defect of opsonophagocytic function seems to participate in the increased susceptibility to infection in cirrhotic patients. Furthermore, whole blood CL induced by nonopsonized zymosan at the onset of relatively severe bacterial infections such as sepsis, pneumonia, or spontaneous bacterial infection was less augmented in the blood of cirrhotic patients than that in noncirrhotic patients. To clarify the reason why whole blood exhibits a lower CL response in the acute phase of bacterial infections, we investigated the priming effects of lipopolysaccharide (LPS) or tumor necrosis factor-α (TNF-α), well-known CL activators, on the CL response of whole blood obtained from cirrhotic patients in comparison with that from healthy persons. The priming effects were significantly decreased in patients’ blood when compared with that of healthy persons. These low responses of patients’ blood to LPS or TNF-α support our finding that phagocytes are not fully activated when gram-negative bacterial infections occur.

Induction of human monocyte chemiluminescence response by an acylated peptidopolygalactose (APPG) from Klebsiella pneumoniae: A role for complement receptor type three (CR3, CD11b/CD18)

Induction of human monocyte chemiluminescence response by an acylated peptidopolygalactose (APPG) from Klebsiella pneumoniae: A role for complement receptor type three (CR3, CD11b/CD18)

Luminol‐amplified chemiluminescence activity in human monocytes: A comparison with the activity induced in granulocytes

The characteristics of the luminol-amplified chemiluminescence (CL) induced in mononuclear phagocytes interacting with PMA, FMLP or ionomycin were determined. Azide reduced the CL activity by more than 80%, while superoxide dismutase and catalase had minor effect on the monocyte CL response. The sensitivity of the monocyte CL response, to the addition of extra peroxidase differed depending on the stimulus used. Furthermore, no direct correlation was obtained between the CL response and superoxide anion or hydrogen peroxide production. In comparison with the response in granulocytes, minor quantitative differences were observed. The mechanism for the light-generating reaction, seems to be the same in both cell types.

Characterization of the Luminol-Amplified Light-Generating Reaction Induced in Human Monocytes

Increased production of oxidative metabolites following interaction between mononuclear phagocytes and soluble stimuli can be measured as luminol-amplified chemiluminescence (CL). The effects of superoxide dismutase (SOD), catalase, and azide on the monocyte CL response were investigated. Azide, a myeloperoxidase (MPO) inhibitor, reduced the CL reaction by more than 80%, which indicates that the CL reaction is dependent on the granule enzyme MPO. Because SOD and catalase only partly inhibited the monocyte CL response, the authors propose that part of the monocyte CL response is of intracellular origin. This conclusion is further supported by the effects on the CL response obtained by adding extra peroxidase and the lack of correlation with techniques measuring only extracellular generated metabolites. However, it should be pointed out that the relation between extracellular and intracellular activity is stimulus dependent. Furthermore, even if quantitative differences exist between monocyte and granulocyte CL, the mechanism for the light-generating reaction seems to be the same in both cell types.

Human monocyte activation induced by an anti-CD14 monoclonal antibody

An anti-CD14 mAb RoMo-1 rapidly induces in human monocytes a transient oxidative burst activity as detected by chemiluminescence assay. Pretreatment of these cells with the mAb markedly suppresses the monocyte chemiluminescence response to opsonized zymosan. In addition, the antibody induces a significant increase of IL-1 production and secretion by mononuclear cells, comparable to a similar effect of rIFN-γ or LPS. Electron microscopy demonstrates internalization of the CD14 molecules after interaction with the mAb in a characteristic receptor-like manner.

Effect of oral N-acetylcysteine administration on human blood neutrophil and monocyte function.

N-acetylcysteine (NAC) is known to be a scavenger of free oxygen radicals, and recent in vitro studies have demonstrated that it is also able to inhibit leukocyte function. The clinical significance of these effects is, however, not known. In this study we have measured the effect on human blood neutrophil and monocyte function of a single 400 mg dose of NAC administered orally. Administration of NAC to ten healthy volunteers resulted in significant reduction of neutrophil chemiluminescence response following activation by opsonized zymosan as compared to four non-treated persons acting as controls. No effect was observed on the chemotaxis of either cell type or on monocyte chemiluminescence response. These findings suggest that NAC may be beneficial in clinical conditions like cystic fibrosis, where tissue damage may be a consequence of the effects of increased release of toxic oxygen radicals and proteolytic enzymes.

Lucigenin-dependent chemiluminescence in mononuclear phagocytes. Role of superoxide anion

A method for the measurement of reactive oxygen species generated by activated mononuclear phagocytes by use of lucigenin-dependent chemiluminescence was developed. Opsonized zymosan was used as a stimulant to evaluate the chemiluminescence response of monocytes. A cell-free system in which superoxide anion and hydrogen peroxide were produced by the xanthine-xanthine oxidase reaction was used to examine the role of these radical species in the excitation of lucigenin, and to standardize the chemiluminescence method. It was found that the light emission in lucigenin-dependent chemiluminescence was evoked by the superoxide anion, but other radicals may also be active.