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

IL-8 is produced by a wide variety of cells in response to polyclonal mitogens and cytokines. Northern blotting analysis revealed that IL-1, TNF and PMA could induce rapid expression of IL-8 mRNA in the absence of new protein synthesis. Nuclear run-off assays using different cell types demonstrated that IL-8 mRNA expression could at least be partly due to the activation of transcription. Cloning and determination of the entire sequence of IL-8 genomic DNA enabled us to explore the functional significance of the 5'-flanking enhancer region of the IL-8 gene by employing CAT assays. The results indicated that the region spanning from -94 to -71 bp is minimally sufficient for conferring responsiveness to IL-1, TNF and PMA. Further analysis using point-mutations revealed that this region consisted of two distinct cis-elements; one being the potential binding site for NFkB-like and the other for a C/EBP-like factor. These results suggested that all three stimuli, IL-1/TNF/PMA, modulate the identical combination of nuclear factors possibly by phosphorylation. We previously reported that these three stimuli activated the same serine protein kinase which phosphorylates identical 65 kDa and 74 kDa cytosol proteins in human PBMC. This IL-1/TNF/PMA-activated protein kinase is distinct from protein kinase A, protein kinase C or casein kinase in substrate specificity; in Ca and phospholipid dependency; in cyclic nucleotide dependency; and sensitivity to protein kinase inhibitors. Taken collectively, IL-1/TNF/PMA may activate a common serine protein kinase and this protein kinase may in turn directly or indirectly modulate several nuclear factors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of human interleukin 8 gene expression and binding of several other members of the intercrine family to receptors for interleukin-8. 175 77

The capacity of human melanocytes and melanoma cells to produce IL-8 and monocyte chemotactic and activating factor (MCAF) was investigated. Melanocytes expressed mRNA for IL-8 and MCAF, when stimulated with either IL-1 alpha or TNF alpha, but not when stimulated with IL-6, IFN gamma, or LPS alone. IL-8 and MCAF could be induced in a dose-dependent fashion with doses as low as 0.1 ng/ml TNF alpha and 0.5 ng/ml IL-1 alpha. IL-8 and MCAF mRNA were rapidly expressed and peaked between 2 and 4 h for IL-8 and between 4 and 8 h for MCAF. This correlated well with the accumulation of IL-8 antigen as measured by a radioimmunoassay. Supernatants from melanocyte cultures stimulated with either IL-1 alpha or TNF alpha and separated on a heparin-Sepharose column became positive for neutrophil and monocyte chemotactic activity in a dose- and time-dependent fashion. When IFN gamma was added to melanocyte cultures stimulated with suboptimal doses of TNF alpha there was a synergistic increase in secreted IL-8 protein and monocyte chemotactic activity. These data provide further evidence for the possible role of melanocytes in the initiation of an inflammatory reaction. Three different malignant melanoma cell lines stimulated with either TNF alpha or IL-1 alpha expressed IL-8 mRNA, but not mRNA for MCAF. The IL-8 mRNA signal corresponded well with the amount of secreted IL-8 protein. These data suggest that IL-8 and MCAF may play a role in growth regulation and spreading of melanomas.
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PMID:Expression and secretion of leukocyte chemotactic cytokines by normal human melanocytes and melanoma cells. 187 58

The cytokine neutrophil-activating peptide-1/interleukin-8 (NAP/IL-8) activates neutrophils (PMN) and elicits selective diapedesis of PMN into the extracellular space. The glomerular mesangial cell (MC) is a specialized pericyte that controls glomerular filtration and synthesizes and responds to a variety of cytokines. Because of its location within the glomerulus, the MC is in a pivotal position to orchestrate events underlying immune injury. Since immune-injured glomeruli have been shown to produce NAP/IL-8 activity in vitro, we assessed whether lipopolysaccharide (LPS)- or cytokine-activated MC might be a source of this activity. Pure human MC, devoid of monocyte/macrophage and fibroblast contamination, were grown by explant from collagenase-treated glomeruli. Human recombinant interleukin-1 alpha (IL-1 alpha, 20 ng/ml), IL-1 beta (50 ng/ml), tumor necrosis factor alpha (TNF, 100 ng/ml) and lipopolysaccharide (LPS, 10 micrograms/ml) stimulated release of a neutrophil chemotactic factor from cultured MC. Both concentrated (fivefold) and unconcentrated MC supernatants stimulated directed neutrophil migration under agarose at a level similar to that of the bacterial chemotactic factor, FMLP. In contrast, unstimulated MC-conditioned media and IL-1 alpha, IL-1 beta. TNF and LPS in medium alone did not directly induce PMN migration. Molecular sizing studies using sequential membrane ultrafiltration identified significant TNF-stimulated, MC-derived chemotactic activity in the 3000 to 10000 kD fraction. An anti-NAP/IL-8 monoclonal antibody, 46E5, significantly inhibited PMN chemotaxis stimulated by TNF-stimulated, MC-conditioned media in a dose-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cytokine- and LPS-induced synthesis of interleukin-8 from human mesangial cells. 189 76

A hyperdynamic sepsis model was set up in seven adult baboons to evaluate neutrophil-activating peptide-1/interleukin (IL)-8 (NAP-1/IL-8), IL-1 beta, IL-6, tumor necrosis factor-alpha (TNF alpha), and IFN-gamma in plasma. By continuous intravenous administration of 10(10) cfu/kg live Escherichia coli over 8 h with additional infusion therapy (less than or equal to 50 ml/kg/h), endotoxin plasma levels of 2.7-22.3 ng/ml were observed. In plasma the kinetics of NAP-1/IL-8 and IL-6 were similar to those of IL-1 at the end of the experiment (8 h) (peak median values, 34, 4197, and 230 ng/ml, respectively). Differences were greatest for IL-6. Monocyte activation during sepsis was confirmed by elevated plasma neopterin levels (91-139 mumol/mmol of creatine). Granulocyte activation was evident from both incipient neutropenia and the massive release of neutrophil elastase into the plasma as measured by a new immunoassay (peak level, 374 ng/ml). Thus, in primate bacteremia, early TNF release is followed by a concomitant increase of NAP-1/IL-8 with plasma kinetics similar to those of IL-6 and IL-1 and accompanied by massive activation of neutrophils.
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PMID:Plasma neutrophil-activating peptide-1/interleukin-8 and neutrophil elastase in a primate bacteremia model. 190 12

Human mesangial cells (MC) in culture, when stimulated by interleukin 1 alpha(IL-1 alpha) or tumour necrosis factor (TNF alpha), but not with lipopolysaccharide (LPS), express interleukin 8 (IL-8) mRNA, and both cell associated and extracellular IL-8. Dexamethasone treatment of mesangial cells induced partial inhibition of the release of extracellular IL-8, while cell-associated IL-8 and IL-8 mRNA were not significantly altered. We propose that the mesangial cell has a direct role in the initiation and propagation of inflammatory events within the glomerulus via the generation of the chemotactic cytokine IL-8.
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PMID:Cytokine-activated human mesangial cells generate the neutrophil chemoattractant, interleukin 8. 192 Nov 60

In the present study we demonstrate that human monocytes activated by lipopolysaccharides (LPS) were able to produce high levels of interleukin 10 (IL-10), previously designated cytokine synthesis inhibitory factor (CSIF), in a dose dependent fashion. IL-10 was detectable 7 h after activation of the monocytes and maximal levels of IL-10 production were observed after 24-48 h. These kinetics indicated that the production of IL-10 by human monocytes was relatively late as compared to the production of IL-1 alpha, IL-1 beta, IL-6, IL-8, tumor necrosis factor alpha (TNF alpha), and granulocyte colony-stimulating factor (G-CSF), which were all secreted at high levels 4-8 h after activation. The production of IL-10 by LPS activated monocytes was, similar to that of IL-1 alpha, IL-1 beta, IL-6, IL-8, TNF alpha, granulocyte-macrophage colony-stimulating factor (GM-CSF), and G-CSF, inhibited by IL-4. Furthermore we demonstrate here that IL-10, added to monocytes, activated by interferon gamma (IFN-gamma), LPS, or combinations of LPS and IFN-gamma at the onset of the cultures, strongly inhibited the production of IL-1 alpha, IL-1 beta, IL-6, IL-8, TNF alpha, GM-CSF, and G-CSF at the transcriptional level. Viral-IL-10, which has similar biological activities on human cells, also inhibited the production of TNF alpha and GM-CSF by monocytes following LPS activation. Activation of monocytes by LPS in the presence of neutralizing anti-IL-10 monoclonal antibodies resulted in the production of higher amounts of cytokines relative to LPS treatment alone, indicating that endogenously produced IL-10 inhibited the production of IL-1 alpha, IL-1 beta, IL-6, IL-8, TNF alpha, GM-CSF, and G-CSF. In addition, IL-10 had autoregulatory effects since it strongly inhibited IL-10 mRNA synthesis in LPS activated monocytes. Furthermore, endogenously produced IL-10 was found to be responsible for the reduction in class II major histocompatibility complex (MHC) expression following activation of monocytes with LPS. Taken together our results indicate that IL-10 has important regulatory effects on immunological and inflammatory responses because of its capacity to downregulate class II MHC expression and to inhibit the production of proinflammatory cytokines by monocytes.
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PMID:Interleukin 10(IL-10) inhibits cytokine synthesis by human monocytes: an autoregulatory role of IL-10 produced by monocytes. 194 Jul 99

NF-IL6 is a nuclear factor that specifically binds to an IL1-responsive element in the IL-6 gene. In this study the gene encoding NF-IL6 has been cloned by direct screening of a lambda gt11 library using NF-IL6 binding sequence as a ligand. The full-length cDNA encoded a 345 amino acid protein with a potential leucine zipper structure and revealed a high degree of homology to a liver-specific transcriptional factor, C/EBP, at the C-terminal portion. The bacterial fusion protein bound to the CCAAT homology as well as the viral enhancer core sequences as in the case of C/EBP. Recombinant NF-IL6 activated the human IL-6 promoter in a sequence-specific manner. Southern blot analysis demonstrated the high-degree conservation of the NF-IL6 gene through evolution and the existence of several other related genes sharing the DNA-binding domain. NF-IL6 mRNA was normally not expressed, but induced by the stimulation with either LPS, IL-1 or IL-6. Interestingly, NF-IL6 was shown to bind to the regulatory regions for various acute-phase protein genes and several other cytokine genes such as TNF, IL-8 and G-CSF, implying that NF-IL6 has a role in regulation not only for the IL-6 gene but also for several other genes involved in acute-phase reaction, inflammation and hemopoiesis.
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PMID:A nuclear factor for IL-6 expression (NF-IL6) is a member of a C/EBP family. 211 87

Monocyte-derived neutrophil chemotactic factor (MDNCF)/IL-8, a novel cytokine, distinct from IL-1 and TNF was recently purified and cloned. This study was performed to investigate the biologic effect of recombinant MDNCF/IL-8 on human polymorphonuclear neutrophils (PMN) by assessment of their growth inhibitory activity against Candida albicans. The chemoattractant, FMLP was used as a positive control. We demonstrated that MDNCF/IL-8, similar to FMLP, effectively enhanced PMN-mediated anti-Candida activity. MDNCF/IL-8, from 1.0 to 1000 ng/mol, enhanced PMN-mediated anti-Candida activity, whereas FMLP was effective from 10(-10) to 10(-7) M. The optimal dose of MDNCF/IL-8 for PMN stimulation was 10 ng/ml which equalled the optimal chemoattractant dose. MDNCF/IL-8 itself, like FMLP, had no direct effect on Candida growth at any concentration and it stimulated antifungal activity only in PMN but not in monocytes. Interestingly, MDNCF/IL-8 failed to stimulate directly the production of superoxide from PMN or prime the respiratory burst of PMN exposed to FMLP. However, MDNCF/IL-8 was capable of releasing azurophilic enzymes from cytochalasin B-treated PMN into the extracellular space. Enhancement of PMN anti-Candida activity and release of azurophilic enzymes from PMN by MDNCF/IL-8 were inhibited in the presence of colchicine, which is a known inhibitor of degranulation. These results suggest that MDNCF/IL-8 induced antifungal action of PMN via oxygen-independent pathways. Furthermore, MDNCF/IL-8 induction of anti-Candida action by PMN was inhibited by pretreatment with Bordetella pertussis toxin, suggesting that enhancement of PMN antifungal activity by MDNCF/IL-8, as well as by FMLP, may be mediated by a GTP-binding protein.
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PMID:Functional activation of human neutrophils by recombinant monocyte-derived neutrophil chemotactic factor/IL-8. 215 63

The liver participates in inflammation via the elaboration of acute phase proteins from hepatocytes in response to IL-1, TNF-alpha, and IL-6/INF-beta 2/hepatocyte-stimulating factor. In addition, some inflammatory states of the liver are characterized by leukocyte infiltrates. Here we demonstrate that human hepatocyte lines are capable of expressing mRNA and biologic activity for a neutrophil chemotactic factor (NCF)/IL-8 in response to the inflammatory mediators IL-1 alpha, IL-1 beta, and TNF. Two human hepatoma cell lines (SK-Hep and Hep-G2) displayed a time- and dose-dependent increase in steady state levels of NCF/IL-8 mRNA and secretion of chemotactic activity in response to TNF and IL-1. Neutralizing antibody to NCF/IL-8 inhibited hepatocyte-derived chemotactic activity by 88%. In contrast to IL-1 and TNF, hepatocytes did not respond to LPS or IL-6 within the time and dose parameters used above. Although the expression of NCF/IL-8 mRNA (1.8 kb) was first detectable between 1 and 2 h poststimulation, significant chemotactic bioactivity was not observed until about 4 h. Heat-inactivated (100 degrees C, 30 min) cytokine failed to induced NCF/IL-8 mRNA synthesis, and cotreatment of cells with cytokine and cycloheximide super-induced NCF/IL-8 mRNA while inhibiting production of bioactivity. Thus, NCF/IL-8 expression is a primary induction phenomenon. Our data demonstrate the stimulus specific induction of NCF/IL-8 in hepatocytes and suggest that cytokine cell-to-cell communication circuits may be important in neutrophil-mediated inflammatory processes in the liver.
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PMID:Cytokine-induced gene expression of a neutrophil chemotactic factor/IL-8 in human hepatocytes. 215 28

There is increasing evidence that epidermal cytokines may have an important role in mediating inflammatory and immune responses in the skin. A number of cell types in the epidermis are capable of secreting cytokines including keratinocytes, Langerhans cells, melanocytic cells, and even Merkle cells. Keratinocytes are the major source of cytokines in the epidermis and have been reported to secrete IL-1, IL-3, IL-6, IL-8, CSF, TNF alpha, TGF alpha, TGF beta, and PDGF. Normally these cytokines are not actively secreted by keratinocytes; however, a number of agents are capable of mediating keratinocyte cytokine production, including cytokines themselves. We examined the effect of a number of cytokines on keratinocyte IL-1, IL-6, GM-CSF, and PDGF production. It was found that these keratinocyte cytokines are all modulated by one or more cytokines, including several that keratinocytes themselves secrete. These effects appear to be mediated by high-affinity cytokine receptors on keratinocytes. We are only beginning to understand the molecular mechanisms underlying the production, regulation, and precise role of keratinocyte cytokines in normal and diseased skin; however, recent studies suggest that cytokines secreted by epidermal cells and lymphoid cells may be important modulators of keratinocyte cytokine production.
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PMID:Cytokine modulation of keratinocyte cytokines. 216 84


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