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Query: UNIPROT:P10145 (IL-8)
 23,849 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interleukin-8 (IL-8) is a neutrophil and lymphocyte chemoattractant and activator that may play an important role in mediating events at sites of inflammation. IL-8 is produced by many cell types in response to a variety of inducers, including interleukin-1 (IL-1). Studies were conducted to address the question of whether an inhibitor of IL-1 action, IL-1 receptor antagonist protein (IRAP), would suppress IL-8 production. Lipopolysaccharide (LPS)-stimulated human whole blood was used as an ex vivo model of local cytokine production. Preliminary time course studies showed that plasma IL-1 beta levels were fully induced by 6 hours (approximately 15 ng/ml) and persisted at this level over 24 hours. IL-8 production, in contrast, reached a plateau between 6 to 12 hours (5 ng/ml) and then increased rapidly to 17 ng/ml at 24 hours. Addition of IRAP was found to dose-dependently inhibit IL-8 expression at the levels of both protein and mRNA. A 50% reduction in IL-8 protein release occurred at an IRAP dose of 8 micrograms/ml (5 x 10(-7) mol/l) at 24 hours. A 2 hour delay in the addition of IRAP relative to LPS still permitted optimal reduction in IL-8 release, whereas delays of 4-8 hours reduced or eliminated the inhibitory effect. IRAP was found to have no effect on the LPS-stimulated production of IL-1 alpha or IL-1 beta. In addition, experiments performed with isolated peripheral blood cells demonstrated that, whereas monocytes were the major producers of IL-8, IRAP was equally effective in reducing IL-8 production in neutrophil and mononuclear cell suspensions. These studies further document the role of IL-1 in inducing the production of IL-8 and indicate that the ability of IRAP to suppress IL-8 expression may be an important mechanism of the anti-inflammatory properties of this molecule.
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PMID:Interleukin-1 receptor antagonist protein inhibits interleukin-8 expression in lipopolysaccharide-stimulated human whole blood. 153 50

IL-8, a cytokine known for its potent and specific neutrophil activation and chemoattractant properties, has been recently detected in the circulation during septic shock, endotoxemia, and after IL-1 alpha administration. Because of its observed in vitro actions, it has been hypothesized that IL-8 may contribute to the dynamics of circulating granulocytes and to the pathologic sequelae seen in sepsis. Here, human rIL-8 is administered to healthy nonhuman primates as a single i.v. injection or as a continuous 8-h i.v. infusion. We demonstrate that both methods of i.v. administration result in a rapid but transient, severe granulocytopenia, followed by a granulocytosis that persists as long as IL-8 levels are detectable in the circulation. There were no hemodynamic changes after IL-8 administration, and animals remained clinically stable during the 24-h observation period. No detectable circulating TNF-alpha, IL-1 beta, or IL-6 response was induced by either IL-8 administration regimen. Histopathologic examination revealed mild to moderate neutrophilic margination in lung, liver, and spleen, of greater severity in baboons receiving the 8-h infusion. There was no associated neutrophilic infiltration or tissue injury. Thus, IL-8 modulates circulating granulocyte dynamics and likely directs their actions, but when administered i.v. to healthy animals, either as a bolus dose or as a continuous infusion for up to 8 h, does not induce the hemodynamic and metabolic aberrations or the acute organ damage seen during sepsis.
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PMID:Effects of intravenous IL-8 administration in nonhuman primates. 154 15

TNF, IL-1, and IL-6 are integral components of the cytokine cascade released in the response to inflammatory stimuli such as LPS. IL-8 is produced both in response to LPS as well as TNF and IL-1. The early, local production of TNF and IL-1 may therefore contribute to the subsequent expression of IL-8. This hypothesis was tested using LPS-stimulated human whole blood as an ex vivo model of local cytokine production. The production of TNF, IL-1 alpha, IL-1 beta, IL-6, and IL-8 was found to be responsive to a wide range of LPS concentrations (0.1 ng/ml-10 micrograms/ml). These cytokines were first detected between 1 to 4 h post-LPS stimulation, and reached plateau levels after 6 to 12 h. IL-8, however, also displayed a secondary wave of production, with the levels again increasing between 12 to 24 h. The IL-8 present in the plasma after LPS stimulation was biologically active, as assessed by neutrophil chemotaxis. In further studies, addition of anti-TNF and anti-IL-1 neutralizing antibodies, alone and in combination, to LPS-stimulated blood resulted in nearly complete ablation of the secondary phase of IL-8 synthesis at both the levels of protein and mRNA, while leaving the first, LPS-mediated phase of IL-8 synthesis unaffected. This model of cytokine production in human whole blood may reflect the sequence of events in a localized environment of inflammation where both a primary stimulus and the induced early cytokine mediators may serve to elicit multiple, temporally distinct phases of IL-8 production.
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PMID:Biphasic production of IL-8 in lipopolysaccharide (LPS)-stimulated human whole blood. Separation of LPS- and cytokine-stimulated components using anti-tumor necrosis factor and anti-IL-1 antibodies. 154 21

Rat cytokine-induced neutrophil chemoattractant (CINC) is a member of the IL-8 family, and its human counterpart is gro/MGSA but not IL-8. We ascertained that chemically synthesized CINC was comparable to native CINC/gro with regard to chemotactic activity for rat neutrophils and studied the effect of synthesized CINC/gro on circulating leukocytes in microvascular vessels of rat mesentery. Exposure of rat mesentery to 10(-8)M authentic CINC/gro induced neutrophil adherence to and extravasation from postcapillary venules (PCVs) but not from capillaries or arterioles. CINC/gro concentrations as low as 10(-10) M were effective in causing neutrophil adherence. Neutrophils adhered to thin PCVs (mean diameter, approximately 25 microns) after exposure to CINC/gro for 15 min. The mean diameters of the PCV with adherence of neutrophils after exposure to CINC/gro for 30 and 60 min were 37 and 43 microns, respectively. The diameters of PCV with extravasation of neutrophils also increased in a time-dependent manner. The starting position of adherence of neutrophils was approximately 25-50 microns away from the upper junction of two vessels and remained virtually unchanged during exposure to CINC/gro for 60 min. However, the distance from the start to the end of neutrophil adherence increased in a time-dependent manner. The effect of CINC/gro on adherence and extravasation of leukocytes was neutrophil specific since other leukocytes such as lymphocytes and monocytes were not identified among the adherent and extravasated leukocytes.
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PMID:Effect of rat CINC/gro, a member of the interleukin-8 family, on leukocytes in microcirculation of the rat mesentery. 154 69

It is evident from this review that TNF exhibits complex interactions with other cytokines at the level of production and in its effects. Studies designed to determine the role of TNF in the animal models or cell culture system using pure recombinant molecules have revealed that TNF never operates by itself, but instead operates within a network of cytokines. First, the multitude of exogenous as well as endogenous signals, which induce TNF production, concomitantly also stimulate the production of a battery of other inflammatory cytokines: IL-1, IL-6, IL-8, multiple CSFs, IFN, and TGF-beta. Moreover, TNF itself stimulates the production of most of these cytokines. Thus even when pure recombinant TNF is used, it readily generates the production of other interactive cytokines. This apparent redundancy in the production of cytokines with overlapping effects presumably has protective advantage for the host. Furthermore, interaction of these cytokines is more economical and amplifies the responses to subtoxic doses of potentially harmful cytokines. Cytokine interaction may lead to either synergistic (as for many TNF-IL-1 interactions) or antagonistic effects (TNF and TGF-beta, for example). These may depend on (1) the modulation of receptor expression of one cytokine by another (IFN-gamma-enhancing receptor expression for TNF, and TGF-beta down-regulation of IL-1 receptors), (2) stabilization of the cytokine message by one another (induction of IL-6 by TNF or IL-1), (3) interactions at the level of signal transduction, (4) gene expression, or (5) at the posttranslational level. Thus the receptor repertoire, which is a function of the cell type and stage of development, actually determines the net effects of a particular combination of interactive cytokines. Clearly, the mechanisms of these interactions will need to be elucidated to better understand their biological function and to permit cytokines to be used clinically to the advantage of the host.
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PMID:Relationship of TNF to interleukins. 155 Aug 74

The respiratory manifestations of cystic fibrosis (CF) are characterized by neutrophil-dominated airway inflammation. Since a variety of inflammatory stimuli are capable of inducing bronchial epithelial cells to express the gene for IL-8, a cytokine that attracts and activates neutrophils, mediators in respiratory epithelial lining fluid (ELF) of CF individuals might induce IL-8 production by epithelial cells, thus recruiting neutrophils to the airways. BET-1A human bronchial epithelial cells at rest or incubated with normal ELF showed little IL-8 gene expression, but after incubation with CF ELF, a marked increase in IL-8 transcript levels was observed. CF ELF contained high levels of neutrophil elastase (NE) and various serine protease inhibitors prevented CF ELF from inducing IL-8 gene expression in BET-1A cells, suggesting that NE was the dominant inducer for IL-8 production in CF ELF. The addition of purified NE caused BET-1A cells to increase IL-8 gene transcription with accumulation of mRNA transcripts and to release IL-8-like neutrophil chemotactic activity. These observations suggest a self-perpetuating inflammatory process on the CF bronchial surface where NE released by neutrophils induced the bronchial epithelium to secrete IL-8, which in turn recruits additional neutrophils to the bronchial surface.
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PMID:Neutrophil elastase in respiratory epithelial lining fluid of individuals with cystic fibrosis induces interleukin-8 gene expression in a human bronchial epithelial cell line. 156 86

IL-8 is a novel chemotactic cytokine, produced by a variety of blood and tissue cells, that has marked activating effects on polymorphonuclear leukocytes (PMN). We report that IL-8 is produced and released by human PMN after stimulation with the chemotactic agonist FMLP. Release of IL-8 in response to FMLP was transient and not influenced by PMN adherence or by the absence of serum in the medium. Maximum yields were usually obtained with 10 nM FMLP within 2 h of stimulation (0.5-3.5 ng/ml/7 x 10(6) cells, range of 17 different donors). IL-8 release was dependent on FMLP-induced de novo protein synthesis because it was inhibited by cycloheximide, was paralleled by enhanced expression of IL-8 mRNA and was potentiated from two- to sixfold after preincubation of PMN with cytochalasin B. The FMLP effect was direct and not dependent on LPS or on contaminating monocytes, which showed only low responsiveness to FMLP. Pretreatment of PMN with pertussis toxin prevented FMLP-dependent IL-8 production, the effect being evident both at the level of mRNA expression and protein secretion. In addition, two other chemoattractans, platelet-activating factor and C5a, were found capable to induce release of IL-8 by PMN. The results of this study suggest that chemotactically stimulated PMN may be able to amplify the recruitment process of PMN to the inflammatory site by releasing IL-8. As a long-lived cytokine, IL-8 could markedly prolong the attractant effect.
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PMID:IL-8 production by human polymorphonuclear leukocytes. The chemoattractant formyl-methionyl-leucyl-phenylalanine induces the gene expression and release of IL-8 through a pertussis toxin-sensitive pathway. 157 46

Idiopathic pulmonary fibrosis is an immunologically mediated pulmonary disorder in which activated alveolar macrophages (AM) and neutrophils play cardinal roles in the pathogenesis of the inflammatory lung lesion. The factors responsible for the induction and perpetuation of the neutrophilic alveolitis are not known. Recently, a novel cytokine (Interleukin-8) was described that is released by activated mononuclear phagocytes and a variety of other cell types, and it exhibits potent chemotactic activity for polymorphonuclear leukocytes (PMN). Increased expression of IL-8 has been described in other inflammatory disorders characterized by neutrophilic infiltration, including psoriasis, rheumatoid arthritis, and the sepsis syndrome, but no studies have assessed this cytokine in the context of interstitial pulmonary disorders. We have previously shown that normal human AM release IL-8 upon appropriate stimulation, but data assessing the expression of IL-8 by human AM in specific pulmonary disease states are lacking. In this study, we examined the expression of steady-state mRNA for IL-8 by human alveolar macrophages obtained by bronchoalveolar lavage (BAL) from patients with idiopathic pulmonary fibrosis (IPF) or sarcoidosis and from healthy volunteers. Because it is known that adherence to plastic culture plates may up-regulate gene expression for IL-8 in the absence of additional stimulation, we extracted mRNA immediately from the cell pellet obtained by BAL rather than using cultured alveolar macrophage monolayers. Northern blot analysis was performed to determine IL-8 mRNA expression. We found that BAL cells from patients with IPF constitutively expressed mRNA for IL-8, and the amount of IL-8 mRNA (as assessed by laser densitometry) correlated with the percent of neutrophils on BAL.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Neutrophilic alveolitis in idiopathic pulmonary fibrosis. The role of interleukin-8. 159 15

In the present study, we show by Northern blot analysis and enzyme linked immunosorbent assay that the Hodgkin's disease (HD)-derived cell lines HDLM-2 and KM-H2 express a variety of cytokine genes either constitutively or upon induction with phorbol ester 12-O-tetradecanoylphorbol-13-acetate. Cytokine genes expressed by HD-derived lines include granulocyte-macrophage colony-stimulating factor (CSF), macrophage-CSF, interleukin (IL)-1-alpha, IL-3, IL-5, IL-6, IL-8, leukemia inhibitory factor, tumor necrosis factor-alpha, tumor necrosis factor-beta, and transforming growth factor-beta, while transcripts and the corresponding proteins for granulocyte-CSF, IL-1-beta, IL-2, IL-4, IL-7, IL-10, and the JE/macrophage chemoattractant and activating factor gene were not detectable in cytoplasmic RNA and culture supernatants obtained from both lines. In addition, IL-2 receptor (R) p55 and macrophage-CSF R (c-fms) genes were expressed by both lines. HDLM-2, but not KM-H2 cells, exhibited the IL-6 R p80 and the IL-2 R p75 chain. Analysis of nuclear proteins that bind to oligonucleotides containing the consensus sequences of the transcription factors activation protein 1, nuclear factor (NF) kappa B, and NFAT 1 revealed a pattern for HD lines resembling that of activated T-cells: HDLM-2 and KM-H2 cells constitutively expressed NF binding to the NF of activated T-cells (type 1), previously described to be T-cell specific. In addition, NF kappa B-binding proteins obtained from both lines showed, in electrophoretic mobility shift assays, the same migration pattern as T-cell-derived proteins but differed from monocyte- and B-cell-derived proteins. UV cross-linking experiments confirmed that NF kappa B-binding proteins of M(r) 85,000, 75,000, and 50,000/55,000 were detectable in nuclear extracts obtained from T-cells and both HD lines, while monocytes and B-cells displayed the M(r) 50,000/55,000 and 75,000 NF kappa B complex only. Both HD lines also constitutively expressed transcripts for c-fos and c-jun, which are involved in heterodimeric formation of the transcription factor activation protein 1, as well as for the NF kappa B/KBF1 gene.
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PMID:Expression of cytokine genes, cytokine receptor genes, and transcription factors in cultured Hodgkin and Reed-Sternberg cells. 159 93

Tuberculosis is a major cause of mortality worldwide and incidence is increasing as a result of the AIDS epidemic. Cytokines such as tumor necrosis factor (TNF) are important in the host response to Mycobacterium tuberculosis. TNF is involved in both granuloma formation and has direct anti-mycobacterial activity. This study investigated the secretion of interleukin (IL)-8 following phagocytosis of M. tuberculosis by a human monocytic cell line and by a more phenotypically mature macrophage-like cell line. M. tuberculosis is shown to be a more potent inducer of IL-8 but not of TNF than bacterial lipopolysaccharide in vitro in both cell types. IL-8 production is partly a consequence of accumulation of mRNA coding for this cytokine. Secretion of IL-8 is not a simple consequence of the phagocytic process but due to the specific interaction M. tuberculosis and the monocyte. IL-8 production was independent of TNF and of virulence of the strain of M. tuberculosis. IL-8 secretion following phagocytosis of M. tuberculosis suggests that this cytokine may be involved in granuloma formation in vivo, possibly acting, in part, as a T cell chemoattractant.
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PMID:Secretion of interleukin-8 following phagocytosis of Mycobacterium tuberculosis by human monocyte cell lines. 160 Oct 32


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