Functional Activities Of Neutrophils Research Articles

The Essential Involvement of the Omentum in the Peritoneal Defensive Mechanisms During Intra-Abdominal Sepsis.

Although the abilities of the omentum to alleviate inflammation and prevent infection have been revealed over the past decades, the underlying mechanisms remain largely unelucidated. Here, we demonstrated that the mortality of mice exposed to cecal ligation and puncture (CLP) and omentectomy was remarkably increased compared to those treated with CLP alone. Moreover, the efficacy of the omentum was associated with an impairment in intraperitoneal bacterial clearance together with an increase in the expression of proinflammatory cytokines. Besides, in response to peritoneal infections, the size and quantity of the omental milky spots (MSs) were increased tremendously and they also support innate-like B1 cell responses and local IgM production in the peritoneal cavity. Furthermore, not only the migration but also the functional activities of neutrophils were diminished in the absence of the omentum. These data collectively show that the omentum contributes more to peritoneal immune responses during septic peritonitis than has heretofore been recognized. Thus, harnessing the function of MS-containing omentum to increase its protective effectiveness may exert important biological and therapeutic implications for the control of intra-abdominal infections.

Functional activities of neutrophils in diabetic rats are changed by yacon extracts

Introduction. Characterization of the polymorphonuclear neutrophils functional activity during the diabetes is of outmost importance for the understanding of the immunological processes involved in disease pathogenesis. The search for effective drugs that would suppress and/or modulate the immune response, preferably without negative effects, is a promising area of modern research. Smallanthus sonchifolius Poepp. et Endl., which has long been used in folk medicine to treat diabetes, was proposed as a potential treatment for immune disorders. The study aimed to search for the effective drug which would be able to regulate neutrophils functional activity in experimentally induced type 1 diabetes mellitus. Material and methods. The experiments were conducted on male Wistar rats. Diabetes was induced by intraabdominal injection of streptozotocin. For the evaluation of phagocytic activity and the content of cationic proteins and myeloperoxidase in neutrophils cytochemical studies were performed. Results. Diabetes development was accompanied by reduced phagocytic activity of granulocytes and increased activity of myeloperoxidase. All used extracts intensified phagocytic activity of neutrophil in diabetes, with the yacon root tubers extract demonstrating the strongest effect, which was reflected by rapid degradation of particles engulfed by phagocytes. Conclusions. It was established that yacon extracts inhibit myeloperoxidase activity in diabetes. Therefore all investigated extracts have a pronounced immunocorrective effect and can become the basis for creating a new generation of antidiabetic drugs.

Effect of abrupt weaning at housing on leukocyte distribution, functional activity of neutrophils, and acute phase protein response of beef calves.

BackgroundSixteen, spring-born, single suckled, castrated male calves of Limousin × Holstein-Friesian and Simmental × Holstein-Friesian dams respectively, were used to investigate the effect of weaning on total leukocyte and differential counts, neutrophil functional activity, lymphocyte immunophenotypes, and acute phase protein response. Calves grazed with their dams until the end of the grazing season when they were housed in a slatted floor shed. On the day of housing, calves were assigned to a treatment, (i) abruptly weaned (W: n = 8) or (ii) non-weaned (controls) (C: n = 8). Weaned calves were housed in pens without their dams, whereas non-weaned (control) calves were housed with their dams. Blood was collected on day -7, 0 (housing), 2, 7, and 14 to determine total leukocyte and differential counts and concentration of fibrinogen and haptoglobin. Lymphocyte immunophenotypes were characterised using selected surface antigens (CD4+, CD8+, WC1+ (γδ T cells), MHC Class II+ lymphocytes), and the functional activities of neutrophils (surface expression of L-selectin (CD62L), phagocytic and oxidative burst activity) were investigated using flow cytometry.ResultsTreatment × sampling time interactions (P < 0.05) were detected for total leukocyte and neutrophil counts, all lymphocyte subsets, mean fluorescence intensity of CD62L+ neutrophils, and percentage neutrophils performing phagocytosis. On d 2, total leukocyte and neutrophil count increased (P < 0.001), and percentage CD4+ and CD8+ lymphocytes, percentage phagocytic neutrophils, mean fluorescence intensity of CD62L+ neutrophils decreased (P < 0.05) in W compared with baseline (d 0), whereas they were unchanged (P > 0.05) in C. On d 2, percentage WC1+ lymphocytes decreased (P < 0.05), whereas percentage MHC class II+ lymphocytes increased (P < 0.05) in W and C, however the magnitude of change was greater in W than C. There were no treatment × sampling time interactions (P > 0.05) for monocyte, eosinophil, and basophil counts, percentage G1+ neutrophils, or percentage oxidative burst positive neutrophils.ConclusionsAbrupt weaning resulted in increased neutrophil counts and impaired trafficking and phagocytic function. Together with the changes in lymphocyte subsets, the results suggest that there was a greater transitory reduction in immune function at housing in abruptly weaned than non-weaned beef calves.

Immunotropic effects of gonadotropin-releasing hormone analog under conditions of emotional painful stress.

Surfagon, a synthetic analog of gonadotropin-releasing hormone injected before emotional painful stress dose-dependently changed the number of antibody-producing cells in rats and phagocytic and functional activities of neutrophils in mice. In castrated animals this peptide increased all studied parameters. This suggests that sex steroids are not involved in the realization of these effects.

Granulocyte colony-stimulating factor modulates the pulmonary host response to endotoxin in the absence and presence of acute ethanol intoxication.

Alcohol impairs neutrophil function and predisposes the host to infectious complications. Granulocyte colony-stimulating factor (G-CSF) increases both the number and functional activities of neutrophils. This study investigated the effects of G-CSF on the pulmonary response to endotoxin in rats with or without acute ethanol intoxication. Acute ethanol intoxication inhibited tumor necrosis factor (TNF)-alpha and macrophage inflammatory protein (MIP)-2 production in the lung and suppressed the recruitment of neutrophils into the lung. Ethanol also inhibited CD11b/c expression on recruited neutrophils and suppressed the phagocytic activity of circulating neutrophils. G-CSF pretreatment up-regulated CD11b/c expression on circulating polymorphonuclear leukocytes, augmented the recruitment of neutrophils into the lung, and enhanced the phagocytic activity of circulating and recruited neutrophils in both the absence and presence of acute ethanol intoxication. G-CSF inhibited MIP-2 but not TNF-alpha production in the lung. These data suggest that G-CSF may be useful in the prevention or treatment of infections in persons immunocompromised by alcohol.

Characterization and identification of interleukin 1 receptors on bovine neutrophils.

Interleukin 1 (IL-1) has been shown to modulate various functional activities of neutrophils, presumably by first binding to cell surface IL-1 receptors. In this study, we characterized and identified IL-1 receptors on bovine neutrophils using direct and competitive receptor binding studies and affinity cross-linking analysis. The results of direct binding studies demonstrated that bovine neutrophils bound 125I-labeled bovine IL-1 by a single affinity binding site (Kd = 4.6 nM, 5600 binding sites per cell). Competitive receptor binding studies demonstrated that unlabeled recombinant bovine IL-1 beta, murine IL-1 alpha, and human IL-1 beta competitively blocked neutrophil binding of 125I-labeled bovine IL-1 beta. In contrast, the IL-1 receptor antagonist (IL-1ra) demonstrated no detectable binding to bovine neutrophils as judged by direct and competitive receptor binding assays. Affinity cross-linking of 125I-labeled bovine IL-1 beta to neutrophils was used to identify cell surface IL-1 receptors. Two specific cross-linked products were observed with molecular sizes of 89 kd (a deduced receptor size of 71.5 kd) and more than 200 kd. The latter may indicate a complex of IL-1 receptor-associated signal-transducing components, IL-1 receptors, and IL-1. The presence of 100 nM unlabeled bovine, murine, or human IL-1 during the receptor binding and cross-linking reactions prevented the formation of cross-linked complexes of 125I-labeled bovine IL-1 beta and its receptor. In contrast, the IL-1ra failed to inhibit the formation of cross-linked complexes of 125I-labeled bovine IL-1 beta and its receptor.

Human Granulocyte Colony-Stimulating Factor: Its Basic Aspects and Clinical Applications

Human granulocyte colony-stimulating factor (G-CSF), a 20 KD glycoprotein consisting of 174 amino acids, is one of the physiological regulators mainly produced by endothelial cells, monocytes-macrophages and fibroblasts, under various stimulations such as infections. The molecule specifically and markedly stimulates the production of neutrophils associated with an expansion of the hematopoietic stem cells/progenitor cells and elevates the functional activities of neutrophils. Under favor of the unique biological activities, recombinant human G-CSF (rhG-CSF) has now become an epoch-making agent for the purposes of reduction of bacterial/fungal infections, particularly in neutropenias of various causes, increased dose intensity of chemotherapeutic drugs in cancers, and solving various problems in hematopoietic stem cell transplantation.

Immunodeficiency of the elderly.

The elderly are at risk for an increased incidence and severity of certain infections. The contribution of age-related immunologic impairment to the pathogenesis of these infections has been difficult to determine because of a number of confounding variables associated with aging. Nevertheless, studies in vitro and in animals support the hypothesis that immunodeficiency accompanies the aging process. Multiple factors may be responsible for altered cell-mediated immunity in the elderly, including thymic involution, reduced levels of thymic hormones, and an increase in the number of immature T lymphocytes. While studies of T cell subpopulations have yielded conflicting results, it appears that T cell proliferative responses are diminished. Aging is also associated with abnormalities of humoral immunity. Although the number and functional activities of neutrophils from healthy elderly persons are relatively intact, diminished bactericidal activity and altered oxygen metabolism have been reported in extremely old individuals. While the relative importance and clinical impact of these immunologic abnormalities remain unclear, future studies may provide new strategies for the prevention and treatment of infections in this rapidly growing segment of the population.