OBJECTIVETo evaluate the variety of non-myeloperoxidase-mediated system activity of neutrophils in newborns during bacterial infection and the effect of cord plasma on the activation of non-myeloperoxidase-mediated system.

METHODSAn infection model with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) and a non-infection model with phorbol-12-myristate-13-acetate (PMA) were established to investigate the activation of non-myeloperoxidase-mediated system in neutrophils. According to the intensity of fluorescence, the activation of non-myeloperoxidase-mediated system of neutrophils was detected by flow cytometry (FCM). The blood cells and plasma were separated from cord blood and adult blood and cross-mixed in order to investigate the opsonic activity.

RESULTSIn the non-infection model, the activation of non-myeloperoxidase-mediated system with PMA stimulation in cord blood was lower compared with that in adult blood, the statistical difference was significant (t = 3.378, P < 0.01). In the infection model, the activations of non-myeloperoxidase-mediated system in cord blood were also lower compared with those in adult blood, while the statistical difference could only be found in the model with E. coli stimulation (t = 12.150, P < 0.001). Furthermore the experiments demonstrated that cord plasma could deeply depress the non-myeloperoxidase-mediated system activity with E. coli stimulation. On the contrary, adult plasma could successfully recruit the potential of non-myeloperoxidase-mediated system activity of neutrophils in newborns.

CONCLUSIONThe function of neonatal neutrophils might not developed very well. As a stimulant, E. coli failed to induce the non-myeloperoxidase-mediated system activity in neonates, which might be related to the lower level of immunoglobulins in cord blood. This result indicated that immunoglobulins played a more important modulating role in bacterial killing during gram-negative bacterial infections.

Escherichia coli ; immunology ; Fetal Blood ; immunology ; Flow Cytometry ; Humans ; Infant, Newborn ; Neutrophils ; enzymology ; immunology ; Peroxidase ; metabolism ; Staphylococcus aureus ; immunology

OBJECTIVETo investigate the influence of neonatal maturity on active oxygen metabolism in neutrophils and possible causes of a high susceptibility to bacterial infection in preterm infants.

METHODSThirty-five preterm infants born at a gestation age of 26-32 weeks (< or =32 weeks group, n=15) and at 33-36 weeks (> 32 weeks group, n=20) and 23 full-term infants (control group) were enrolled in this study. The samples of whole cord blood from the two preterm groups and the control group were stimulated in vitro with live bacteria,Staphylococcus aureus ( S. aureus) and Escherichia coli (E. coli) and stained with hydroethedine, an indicator of superoxide. The percentage of neutrophils which produced superoxide and the mean fluorescence intensity for superoxide production were measured by flow cytometry. The incidence of bacterial infection during hospital stay was compared between the two preterm groups.

RESULTSUnder S. aureus or E. coli stimulation, the percentage of neutrophils which produced superoxide in the < or =32 weeks group was significantly lower than that of the > 32 weeks group and the control group (P < 0.01). The percentage of neutrophils which produced superoxide was closely related to gestational age in preterm infants ( y=2.66 x, P < 0.01).There were no significant differences in the blood level of superoxide production in neutrophils among the three groups. The incidence of bacterial infection during hospital stay in the < or =32 weeks group (40%) was significantly higher than that the > 32 weeks group (10%) (P < 0.05).

CONCLUSIONSThe capability of active oxygen metabolism in neutrophils was significantly related to the gestational age in preterm infants. The decreased capability of active oxygen metabolism might be contributed to a higher susceptibility to bacterial infection in preterm infants.

Disease Susceptibility ; Gestational Age ; Humans ; Infant, Newborn ; Infant, Premature ; immunology ; Neutrophils ; metabolism ; Superoxides ; metabolism

OBJECTIVETo study the regulation of Fc receptor expression by immune complexes (ICs) on neutrophils and U937 cells.

METHODSIgA ICs, IgG1 ICs, IgG2 ICs, IgG3 ICs, IgG4 ICs, and IgM ICs were incubated with neutrophils or U937 cells for 1 h. Then their surface Fc receptors were stained by anti-Fc gammaR I, anti-Fc gammaR II , anti-Fc gammaR III, and anti-Fc alphaR I monoclonal antibodies and analyzed by fluorescent activated cell sorting (FACS).

RESULTSIgG1 ICs and IgG3 ICs up-regulated Fc gammaR II and Fc gammaR III on U937 cells, Fc gammaR I and Fc alphaR I on neutrophils. Almost all ICs down-regulated Fc gammaR II on neutrophils.

CONCLUSIONSICs can regulate Fc receptor expression on neutrophils and U937 cells, among which IgG1 ICs and IgG3 ICs are most effective.

Antibodies, Anti-Idiotypic ; immunology ; Antibodies, Monoclonal ; pharmacology ; Antigen-Antibody Complex ; immunology ; metabolism ; Antigens, CD ; immunology ; Humans ; Immunoglobulin A ; classification ; immunology ; Immunoglobulin G ; chemistry ; classification ; immunology ; metabolism ; Neutrophils ; metabolism ; Receptors, Fc ; biosynthesis ; genetics ; Receptors, IgG ; immunology ; U937 Cells ; immunology

This study was performed to evaluate the effect of granulocyte-colony stimulating factor on neutrophil functions in diabetic patients with active foot infections in vitro. Twelve diabetic patients with foot infections and 12 normal volunteers were enrolled. Neutrophils from peripheral blood were incubated with granulocyte colony-stimulating factor (G-CSF, 50 ng/mL) for 20 min. Superoxide production of neutrophils was measured by the reduction of ferricytochrome C. Neutrophil phagocytosis was assayed using Staphylococcus aureus and the weighted phagocytic index was calculated. Superoxide production of neutrophils in diabetic patients with foot infections was 7.7 (unit: nmol/2 x 10(5) cells/60 min), which was significantly lower than that in controls (12.0) (p<0.05). G-CSF increased neutrophil superoxide production to 12.1 in diabetic patients with foot infections and to 19.8 in controls (p<0.05 for each). Weighted phagocytic index in diabetic patients with foot infections was 0.77, which was not significantly different from that of the controls (0.69). Weighted phagocytic index was increased significantly by G-CSF to 0.88 in diabetic patients with foot infections and to 0.79 in controls (p<0.05 for each). In conclusion, G-CSF significantly enhanced neutrophil functions in diabetic patients with foot infections in vitro.
Adult ; Aged ; Bacterial Infections/immunology* ; Diabetes Mellitus/immunology* ; Female ; Foot Diseases/immunology* ; Granulocyte Colony Stimulating Factor, Recombinant/pharmacology* ; Human ; Male ; Middle Age ; Neutrophils/immunology ; Neutrophils/drug effects* ; Receptors, IgG/analysis ; Superoxides/metabolism

Trichomonas vaginalis is a flagellated lumen-dwelling extracellular protozoan parasite that causes human trichomoniasis via sexual intercourse. Human neutrophils play a crucial role in acute tissue inflammatory responses in T. vaginalis infection. In this study, we investigated the signaling mechanism of neutrophil responses when stimulated with T. vaginalis-derived secretory products (TvSP), which were collected from 1x10(7) live trichomonads. Incubation of human neutrophils isolated from peripheral blood with TvSP induced up-regulation of IL-8 protein secretion. In addition, stimulation with TvSP induced phosphorylation of NF-kappaB and CREB in neutrophils. Moreover, TvSP-induced IL-8 production was also significantly inhibited by pretreatment of neutrophils with ikappaB inhibitor or CREB inhibitor. These results suggest that transcription factors NF-kappaB and CREB are involved in IL-8 production in human neutrophils induced by stimulation with T. vaginalis infection.
Cyclic AMP Response Element-Binding Protein/*metabolism ; Human Experimentation ; Humans ; Interleukin-8/*metabolism ; Male ; NF-kappa B/*metabolism ; Neutrophils/*immunology ; Phosphorylation ; Trichomonas vaginalis/*immunology

OBJECTIVETo investigate the neuro-protective effect of Xuesaitong Injection (XST) on brain inflammatory response after transient focal cerebral ischemia/reperfusion in rats.

METHODSFocal cerebral ischemia/reperfusion models of male rats were induced by transient occlusion for 2 h of middle cerebral artery (MCA) which was followed by 24 h reperfusion. XST was administered through intraperitoneal injection of 25 mg/kg or 50 mg/kg at 4 h after the onset of ischemia. After reperfusion for 24 h, the neurological function score was evaluated, the brain edema was detected with dry-wet weight method, the myeloperoxidase (MPO) activity and the expression of intercellular adhesion molecule-1 (ICAM-1) of ischemic cerebral cortex and caudate putamen was determined by spectrophotometry and immunohistochemistry respectively.

RESULTSXST not only lowered neurological function score at the dose of 50 mg/kg, but reduced brain edema and inhibited MPO activity and ICAM-1 expression as compared with the ischemia/reperfusion model group (P < 0.01).

CONCLUSIONXST has a definite effect on inhibiting the expression of ICAM-1 and neutrophil infiltration in rats with cerebral ischemia/reperfusion when treatment started at 4 h after ischemia onset, and also attenuates inflammation in the infarcted cerebral area.

Animals ; Brain Edema ; drug therapy ; immunology ; Brain Ischemia ; drug therapy ; immunology ; Encephalitis ; drug therapy ; immunology ; Intercellular Adhesion Molecule-1 ; metabolism ; Male ; Neuroprotective Agents ; pharmacology ; Neutrophils ; immunology ; Peroxidase ; metabolism ; Rats ; Rats, Wistar ; Reperfusion Injury ; drug therapy ; immunology ; Saponins ; pharmacology

BACKGROUNDCorticosteroid treatment of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) has been one of the most controversial clinical issues in critical care. Although the administration of high-dose corticosteroids does not benefit patients with early septic shock and ARDS, recent clinical trials have indicated that treatment with relatively low-dose corticosteroids (2 to 3 mg/kg/day of methylprednisolone or equivalent) may improve outcome when used for late ARDS or persistent septic shock. The underlying mechanism was not fully clarified. Whether the administration of corticosteroids can arrest neutrophil-driven organ injury once started remains to be elucidated.

OBJECTIVETo observe the effects of hydrocortisone (HC, 6 mg/kg) on oxygen free radicals (OFR) released by PMN and pulmonary pathological changes in rat ALI model induced by lipopolysaccharide (LPS), to investigate the possible mechanism through which corticosteroids exert protective effect on ALI.

METHODSA rat model of ALI was induced by peritoneal injection of 2 x 10(12) Escherichia coli/kg. Fifty-six rats were randomly divided into three groups: normal control group, LPS group and HC group (6 mg/kg). Samples were collected 2 h, 4 h and 6 h after giving LPS to LPS and HC group (6 h after giving normal saline in normal control group) to measure the level of OFR released by PMN using chemiluminescence method based on lumino, and to compae of pulmonary pathological changes among the three groups.

RESULTSPathological examination with light microscope in LPS group showed thickened pulmonary interstitia, inflammatory cell infiltration, edema and hemorrhage, which were in accordance with the features of ALI. There were significant differences in the release of OFR by PMN among the three groups (P < 0.01). The level of OFR released by PMN in LPS group was significantly higher than that of the control group, and continued to increase during the observation period (2 - 6 h after LPS). The release of OFR by PMN in HC group was significantly suppressed as compared with LPS group, which was peaked at 4 h after LPS injection (to 98.2%); there were also significant differences in the grades of ALI pathologic changes among the three groups (P < 0.01). The grades of ALI pathologic changes in LPS group were significantly increased when compared with the normal control group (P < 0.05) while significantly decreased in HC group as compared with LPS group (P < 0.05).

CONCLUSIONIt was demonstrated in the LPS induced ALI model that OFR might play an important role in onset of ALI. Intervening with HC (6 mg/kg) treatment could ameliorate the lung injury and exert significant and sustained suppression on the release of OFR by PMN, showing that HC has a protective effect on LPS induced ALI and its theraputic effect occurs possibly through suppression on the release of OFR by PMN.

Acute Lung Injury ; etiology ; immunology ; Animals ; Disease Models, Animal ; Free Radicals ; metabolism ; Glucocorticoids ; pharmacology ; Hydrocortisone ; pharmacology ; Lipopolysaccharides ; adverse effects ; Lung ; immunology ; pathology ; Mice ; Neutrophils ; drug effects ; metabolism

Tyrosine kinases are one of the most important regulators for intracellular signal transduction related to inflammatory responses. However, there are no reports describing the effects of tyrosine kinases on neutrophil apoptosis induced by Entamoeba histolytica. In this study, isolated human neutrophils from peripheral blood were incubated with live trophozoites in the presence or absence of tyrosine kinase inhibitors. Entamoeba-induced receptor shedding of CD16 and PS externalization in neutrophils were inhibited by pre-incubation of neutrophils with the broad-spectrum tyrosine kinase inhibitor genistein or the Src family kinase inhibitor PP2. Entamoeba-induced ROS production was also inhibited by genistein or PP2. Moreover, genistein and PP2 blocked the phosphorylation of ERK and p38 MAPK in neutrophils induced by E. histolytica. These results suggest that Src tyrosine kinases may participate in the signaling event for ROS-dependent activation of MAPKs during neutrophil apoptosis induced by E. histolytica.
*Apoptosis ; Cells, Cultured ; Entamoeba histolytica/*immunology/*pathogenicity ; GPI-Linked Proteins/metabolism ; Genistein/metabolism ; Humans ; Neutrophils/*immunology ; Protein Kinase Inhibitors/metabolism ; Pyrimidines/metabolism ; Reactive Oxygen Species/metabolism ; Receptors, IgG/metabolism ; src-Family Kinases/antagonists & inhibitors/*metabolism

Neutrophil adhesion and migration are critical in hepatic ischemia/reperfusion (I/R) injury. Despite very strong preclinical data, recent clinical trials failed to show a protective effect of anti-adhesion therapy in reperfusion injury. Therefore, the aim of this study was to assess the role of CD44 in neutrophil infiltration and liver injury from hepatic I/R. In this study, using a partial hepatic ischemic model in vivo, we determined the potential role of CD44 in neutrophil infiltration and liver injury from I/R. Reperfusion caused significant hepatocellular injury as it was determined by plasma ALT levels and liver histopathology. The injury was associated with a marked neutrophil recruitment and CD44 expression into the ischemic livers. Administration of anti-CD44 antibody to mice reduced the infiltration of neutrophil into the ischemic tissue, associated with liver function preservation. These results support crucial roles of CD44 in neutrophil recruitment and infiltration leading to liver damage in hepatic I/R injury. Moreover, they provide the rationale for targeting to CD44 as a potential therapeutic approach in liver I/R injury.
Alanine Transaminase/blood ; Animals ; Antibodies/immunology/pharmacology ; Antigens, CD44/immunology/metabolism/*physiology ; Cytokines/metabolism ; Disease Models, Animal ; Liver/*metabolism/pathology ; Male ; Mice ; Mice, Inbred C57BL ; Neutrophils/immunology/physiology ; Reperfusion Injury/metabolism/pathology/*prevention & control

Lipooligosacharide (LOS) of Neisseria gonorrhoeae (gonococci, GC) is involved in the interaction of GC with host cells. Deletion of the alpha-oligosaccharide (alpha-OS) moiety of LOS (lgtF mutant) significantly impairs invasion of GC into epithelial cell lines. GC opacity (Opa) proteins, such as OpaI, mediate phagocytosis and stimulate chemiluminescence responses in neutrophils in part through interaction with members of the carcinoembryonic antigen (CEA) family, which includes CEACAM3 (CD66d), a human neutrophil specific receptor for phagocytosis of bacteria. In the present work, we examined the effects of OpaI-expressing lgtF mutant on phagocytosis by HeLa-CEACAM3 cells and chemiluminescence responses in neutrophils. The results showed that lgtF mutant even expressing OpaI completely lost the ability to promote either phagocytosis mediated by CEACAM3 interaction in HeLa cells or chemiluminescence responses in neutrophils. These data indicated that Opa proteins in the lgtF mutant, which might result from the conformational change, cannot be functional.
Antigens, Bacterial ; chemistry ; genetics ; immunology ; metabolism ; Carbohydrate Sequence ; Carcinoembryonic Antigen ; genetics ; immunology ; Gene Expression Regulation ; HeLa Cells ; Host-Pathogen Interactions ; Humans ; Lipopolysaccharides ; chemistry ; immunology ; Luminescent Measurements ; Mutation ; Neisseria gonorrhoeae ; genetics ; metabolism ; pathogenicity ; Neutrophils ; immunology ; microbiology ; Phagocytosis