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Leucocyte Activation (leucocyte + activation)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

A carbohydrate neoepitope that is up-regulated on human mononuclear leucocytes by neuraminidase treatment or by cellular activation

IMMUNOLOGY, Issue 2 2001
Mark T. Quinn
Summary The expression of cell-surface antigens can delineate specific leucocyte developmental or functional stages. For example, certain membrane glycoproteins are expressed selectively on leucocyte subsets only after activation. Leucocyte activation can also induce changes in carbohydrate epitopes expressed on surface antigens. In the present studies, we report on a novel monoclonal immunoglobulin M antibody (mAb 13.22) that recognizes a unique carbohydrate epitope expressed on human leucocyte membrane proteins. Characterization of mAb 13.22 specificity by immunoblotting showed that it recognized proteins of MW ,95 000 and 150 000, including both CD18 and CD11b. The mAb 13.22 epitope was removed by N -glycosidase F but not by endoglycosidase H or fucosidase, demonstrating that it is an N-linked carbohydrate antigen. Interestingly, immunoblot staining was enhanced after neuraminidase treatment, suggesting that the antibody epitope might also be partially masked by sialic acid. In resting leucocytes, the mAb 13.22 antigen was expressed strongly on neutrophils, while dull staining was present on monocytes, and no lymphocyte staining was observed. In marked contrast, treatment of leucocytes with neuraminidase resulted in exposure of a mAb 13.22 neoepitope on a subset of lymphocytes (primarily T lymphocytes and natural killer cells) as well as up-regulated staining more than 18-fold on monocytes. Activation of lymphocytes in culture with phytohaemagglutinin or concanavalin A also unmasked the mAb 13.22 neoepitope on ,37% of the CD45RO+ lymphocytes. Furthermore, analysis of leucocytes collected from the synovial fluid of patients with rheumatoid arthritis showed that ,18% of the lymphocytes present expressed the mAb 13.22 neoepitope. Taken together, our results suggest that the mAb 13.22 carbohydrate neoepitope could represent a physiologically relevant marker that is up-regulated on leucocyte subsets during the inflammatory response. [source]

Heightened levels of circulating 20S proteasome in critically ill patients

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 6 2005
G. A. Roth
Abstract Background, Recently, circulating proteasome core particles (20S proteasome) have been suggested as a marker of cell damage and immunological activity in autoimmune diseases. Aberrant leucocyte activation and increased lymphocyte apoptosis with consecutive T-cell unresponsiveness is deemed to play a pivotal role in the sepsis syndrome. Moreover sepsis-induced muscle proteolysis mainly reflects ubiqutin proteasome-dependent protein degradation. We therefore sought to investigate serum levels of 20S proteasome in critical ill patients. Material and methods, Case,control-study at a university hospital intensive care unit; 15 patients recruited within 24,48 h of diagnosis of sepsis, 13 trauma patients recruited within 24 h of admission to the ICU, a control group of 15 patients who underwent abdominal surgery, and 15 healthy volunteers. ELISA was used to measure the concentration of 20S proteasome in the sera of the patients and controls. Data are given as mean ± SEM. Mann,Whitney U -test was used to calculate significance and a P -value of 0·05 was considered to be statistically significant. Results, Marked increase of 20S proteasome was detected in the sera of septic patients (33 551 ± 10 034 ng mL,1) as well as in trauma patients (29 669 ± 5750 ng mL,1). In contrast, significantly lower concentrations were found in the abdominal surgery group (4661 ± 1767 ng mL,1) and in the healthy control population (2157 ± 273 ng mL,1). Conclusion, Detection of 20S proteasome may represent a novel marker of immunological activity and muscle degradation in sepsis and trauma patients, and may be useful in monitoring the clinical effect of proteasome-inhibitors. [source]

Polaprezinc attenuates the Helicobacter pylori -induced gastric mucosal leucocyte activation in Mongolian gerbils,a study using intravital videomicroscopy

ALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 5 2001
H. Suzuki
Background: We previously demonstrated that Helicobacter pylori colonization evokes gastric mucosal inflammation and an extensive increase in lipid peroxides and glutathione in Mongolian gerbils. Zinc and its derivative, polaprezinc, have been reported to be potent antioxidants in gastric mucosa. Aim: To examine the effect of polaprezinc on gastric mucosal oxidative inflammation in H. pylori -colonized Mongolian gerbils. Methods: Sixty-eight male Mongolian gerbils were orally inoculated with H. pylori (ATCC43504, 5 × 108 CFUs/gerbil; H. pylori group) and 35 gerbils were inoculated with the culture media (control group). Twenty-two gerbils in the H. pylori and 13 gerbils in the control group were fed with diets containing polaprezinc (0.06%, 100 mg/kg, 10 times the usual clinical dose) (H. pylori + polaprezinc group, polaprezinc group). The remaining gerbils were fed a standard laboratory chow diet. Neutrophil infiltration, assessed histologically and by the activity of myeloperoxidase, the contents of CXC-chemokine (GRO/CINC-1-like protein) and the contents of thiobarbituric acid-reactive substances, was evaluated in each group 12 weeks after the inoculation. Separately, gastric mucosal leucocyte activation and capillary perfusion were also assessed using intravital microscopy 2, 4, 8 and 12 weeks after the inoculation. Results: In all H. pylori -inoculated animals, the bacterial infection persisted throughout the experimental period. Gastric mucosal lesion formation in the H. pylori group was significantly inhibited in the H. pylori + polaprezinc group. Elevated levels of myeloperoxidase activity, GRO/CINC-1 and thiobarbituric acid-reactive substances in the H. pylori group at 12 weeks were attenuated significantly by polaprezinc treatment. Enhanced levels of venular leucocyte activation observed in the H. pylori group were attenuated significantly in the H. pylori + polaprezinc group during both the early phase (2 weeks) and late phase (12 weeks). Conclusion: Polaprezinc inhibited H. pylori -associated gastric mucosal oxidative inflammation, including initial micro-vascular leucocyte activation, in Mongolian gerbils. [source]

Strongly increased levels of fibrinogen elastase degradation products in patients with ischemic stroke

BRITISH JOURNAL OF HAEMATOLOGY, Issue 5 2008
Lonneke M. L. De Lau
Summary Ischemic stroke is associated with leucocyte activation. Activated leucocytes release elastase, an enzyme that can degrade fibrinogen. Fibrinogen elastase degradation products (FgEDP) may serve as a specific marker of elastase proteolytic activity. In a case-control study of 111 ischemic stroke patients and 119 controls, significantly higher FgEDP levels were observed in cases than in controls, both in the acute phase and in the convalescent phase. Results were only slightly affected by adjustment for cardiovascular risk factors, C-reactive protein and fibrinogen. Our findings suggest that FgEDP might be involved in the pathogenesis of stroke. [source]