No abstract

Helicobacter pylori neutrophil-activating protein (HP-NAP) is a virulence factor that activates phagocytic NADPH-oxidase. The effect of HP-NAP on the production of tissue factor (TF), plasminogen activator inhibitor-2 (PAI-2), and urokinase-type plasminogen activator (u-PA) by human blood mononuclear cells (MNC) was evaluated by using functional and immunological assays and mRNA analysis. HP-NAP induced time- and dose-dependent increases in TF and PAI-2, with a maximal effect at 300 nmol/L (>15-fold increase in antigens). No changes in u-PA were observed. When whole bacteria were used, an H. pylori mutant lacking HP-NAP was significantly less active than the wild-type strain. MNC from a patient with chronic granulomatous disease behaved as do normal cells, which indicates that HP-NAP effects can occur independently of NADPH-oxidase. HP-NAP, by inducing the coordinate expression of cell procoagulant and antifibrinolytic activities, might favor fibrin deposition and contribute to the inflammatory reaction of gastric mucosa elicited by H. pylori.

No abstract

The role of colony stimulating factors (CSFs) in cystic fibrosis (CF) circulating neutrophils has not been thoroughly evaluated, considering that the neutrophil burden of lung inflammation in these subjects is very high. The aim of this study was to assess granulocyte-CSF (G-CSF) and granulocyte-macrophage-CSF (GM-CSF) levels in CF patients in various clinical conditions and how these cytokines impact on activation and priming of neutrophils. G-CSF and GM-CSF levels were measured in sputum and serum samples of stable CF patients (n = 21) and in CF patients with acute exacerbation before and after a course of antibiotic therapy (n = 19). CSFs were tested on non CF neutrophils to investigate their effects on reactive oxygen species (ROS) production, degranulation (CD66b, elastase, lactoferrin, MMP-9), and chemotaxis. At very low concentrations found in CF patients (0.005–0.1 ng/ml), both cytokines inhibited ROS production, while higher concentrations (1–5 ng/ml) exerted a stimulatory effect. While either CSF induced elastase and MMP-9 secretion, lactoferrin levels were increased only by G-CSF. Chemotaxis was inhibited by GM-CSF, but was increased by G-CSF. However, when present together at low concentrations, CSFs increased basal and fMLP-stimulated ROS production and chemotaxis. These results suggest the CSF levels that circulating neutrophils face before extravasating into the lungs of CF patients may enhance their function contributing to the airway damage.

Different Helicobacter pylori lipopolysaccharides (LPSs) and LPS-derivatives were studied for their ability to induce the production of procoagulant activity (PCA) and plasminogen activator inhibitor type 2 (PAI-2) by human blood mononuclear leukocytes. Smooth (S)- and rough (R)-form LPSs caused a similar increase in cell-associated PCA (tissue factor) and PAI-2 antigen release. Both effects were potentiated by fetal bovine serum via a CD14-mediated mechanism. The potency of H. pylori LPSs was approximately 1000-fold lower than that of Salmonella typhimurium LPSs. When H. pylori LPS derivatives (dephosphorylated R-LPS, S-lipid A, and R-lipid A) were used, PCA and PAI-2 production were markedly reduced. R-lipid A was approximately 4-fold less efficient than S-lipid A. These findings suggest that the induction of monocyte tissue factor and PAI-2 by H. pylori LPS is influenced by the lipid A structure and modulated by the core oligosaccharide and that phosphate groups present in both regions may play an important role.