Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Production of interleukin-6 (IL-6) by the Th2 subset of murine T cells supposedly contributes to regulation of humoral immunity. Little information exists on IL-6 production by human T cells. We examined the requirements for IL-6 production by purified human blood T cells, completely depleted of IL-6-producing monocyte-accessory cells. Immobilized anti-CD3 mAb alone (coated on the culture wells) was unable to induce IL-6 production, although it could induce production of IL-2 and TNF-alpha. Addition of rIL-1 beta as an accessory signal to anti-CD3-stimulated human T cells induced IL-6 mRNA expression and protein secretion, while IL-2, IL-4, GM-CSF, IFN-gamma, or TNF-alpha did not have any effect. In the presence of IL-1 beta, both CD4+ and CD8+ T cells were able to produce IL-6. We also demonstrated that phorbol 12-myristate 13-acetate (PMA) or triggering of the CD28 molecule is an effective helper signal for IL-6 production by anti-CD3-stimulated T cells. Efficient CD28 ligation was done either by anti-CD28 mAb or by binding to its natural ligand B7/BB1, presented on the 3T6 mouse fibroblast cell line coexpressing transfected human Fc gamma RII (CD32) (to immobilize anti-CD3) and B7/BB1. Finally, we found that combinations of IL-1 beta with anti-CD28 mAb or PMA with anti-CD28 mAb were highly synergistic helper signals for IL-6 production. We conclude that IL-6 production by T cells is not induced by T cell receptor triggering alone, but different intracellular signaling pathways activated by IL-1 beta, CD28 ligation, or PMA efficiently coinduce IL-6 production.
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PMID:Interleukin-1 and B7/CD28 interaction regulate interleukin-6 production by human T cells. 750 12

Immunoglobulin is known to be an immunomodulator. It can induce protein mediators from mononuclear cells, particularly monocytes in vitro. Intravenous immunoglobulin (IVIg) has been used as a therapy in several clinical situations. In this study, the influence of IVIg infusion on the plasma levels of two protein mediators, interferon-gamma (IFN-gamma) and interleukin-6 (IL-6), was assessed in patients with secondary generalized epilepsy. Compared to preinfusion levels, plasma interferon-gamma was increased in 18 of 18 patients 20 min after the 6- to 8-hr infusion of IVIg. Plasma interferon-gamma levels reached their peak at various times from 20 min to 3 days post IVIg infusion, dependent upon the individual patient. Plasma IL-6 levels also increased after IVIg infusion. Generally, IL-6 reached its peak level after IFN-gamma. No activated T cells or B cells were observed as determined by the expression of surface CD25, CD23, and HLA-DR 20 min following the infusion when the IFN-gamma and IL-6 levels were assessed. The expression of the high-affinity receptor for IgG, CD64, on monocytes was significantly enhanced after IVIg infusion, while the low-affinity receptor for IgG, CD32, was only slightly increased. Cytoplasmic staining of PBMC indicates that both CD16-positive and CD16-negative cells may contribute to the increase seen in plasma IFN-gamma. These data raise the possibility that the therapeutic effects of intravenous immunoglobulin may be related, at least in part, to the immunomodulatory activity as demonstrated by the changes in plasma levels of IFN-gamma and IL-6.
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PMID:Intravenous immunoglobulin induces interferon-gamma and interleukin-6 in vivo. 824 76

The expression of Fc receptors for IgG (Fc gamma R) and IgA (Fc alpha R) and of various other antigens on the human monocytic cell line U937 and peripheral blood monocytes, under stimulation with human recombinant tumour necrosis factor-alpha (TNF-alpha) and other cytokines, was investigated by flow cytometry. TNF-alpha, as well as interferon-gamma (IFN-gamma) or interleukin-6 (IL-6) had a significant up-regulating effect on U937 expression of Fc gamma RI/CD64. Furthermore, the action of TNF-alpha was augmented by IL-6, and more evidently by IFN-gamma. IFN-alpha alone had only a marginal effect, but was able to increase the TNF-alpha-driven Fc gamma RI expression. In contrast to U937 cells, TNF-alpha did not enhance significantly Fc gamma RI expression on human monocytes. Interestingly, on both U937 cells and monocytes, Fc alpha R was augmented markedly by TNF-alpha. Furthermore, TNF-alpha induced the expression of HLA-DR and HLA-DP antigens on monocytes and U937 cells. The expression of Fc gamma RII/CD32, FC gamma RIII/CD16, CD14, complement receptor type 1 (CR1/CD35), CR4 (CD11c/CD18), and MHC class-I antigens, was not influenced significantly by TNF-alpha. The results of this study show that TNF-alpha may act on human mononuclear phagocytes, alone or in combination with other cytokines, by modulating the expression of various cell-surface antigens.
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PMID:Influence of tumour necrosis factor-alpha on the expression of Fc IgG and IgA receptors, and other markers by cultured human blood monocytes and U937 cells. 829 57

Six macrophage cell lines, each derived from a bone marrow macrophage colony grown in soft agar, were established by expansion of the macrophage clones in liquid culture until spontaneous transformation occurred. Four lines originated from the LPS(d) nonresponder mouse strain C3H/HeJ and two from the LPS(n) responder strain CBA/J. The cell lines adhered to plastic and glass surfaces and displayed typical macrophage functions such as phagocytosis and nonspecific esterase activity. Flow cytometry analyses showed that the lines expressed the macrophage surface markers CD11b, CD13, CD32/16, F4/80, and BM8 constitutively. A moderate expression of the adhesion receptor CD11a, but only a very low expression of its ligand CD54, was observed. A minor fraction of the cells in each line constitutively expressed MHC class II antigen, and its expression could be up-regulated in each cell line by treatment with interferon-gamma (IFN-gamma). Secretion of the inflammatory mediators nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-alpha) after induction by three bacterial derivatives, heat-killed Salmonella typhimurium (HKS), lipopolysaccharide (LPS), and the Mycoplasma fermentans-derived amphiphilic lipid MDHM, were examined in detail. Not only did the lines differ in the amounts of mediators secreted in response to any one stimulus, but the doses of MDHM or LPS required for 50% maximal induction of NO varied up to 10-fold among the four LPS(d) cell lines, suggesting considerable functional heterogeneity between the clones. Secretion of large amounts of TNF-alpha was induced in all the cell lines by HKS. Although it could be shown that exogenously added TNF-alpha acted synergistically with IFN-gamma to induce NO release from the cell lines, an autocrine role for TNF-alpha during HKS-IFN-gamma induction of NO synthesis could not be substantiated. Neutralization of TNF-alpha with a specific antibody completely blocked NO induction by exogenous TNF-alpha but did not abrogate NO release either by HKS-IFN-gamma-induced cells or by macrophages treated with supernatant from an HKS-IFN-gamma-activated cell line. These results indicate that the clones are arrested in distinct stages of differentiation and retain some properties of normal untransformed macrophages. They should be helpful tools for investigations into macrophage function.
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PMID:Characterization of clonally derived, spontaneously transformed bone marrow macrophage cell lines from lipopolysaccharide hyporesponsive LPS(d) and normal LPS(n) mice. 910 34

Interaction between leukocyte and endothelial cells (ECs) is essential for vascular homeostasis and competent immune-inflammatory responses in vivo. Platelet-derived microparticles (PMPs) are generated by high shear stress and may appear in diseased small arteries and arterioles in various clinical settings. In this study, we used flow cytometry and confocal laser scanning microscopy to investigate the effects of high-shear-induced platelet and microparticle activation in adhesion molecules of THP-1 and ECs. We also measured the production of some cytokines and studied cytokine mRNA from THP-1 and ECs after PMP stimulation. PMP stimulation of THP-1 cells increased CD11b, CD32, and CD33 but not CD29, CD31, and CD36. PMP stimulation of ECs increased CD54 and CD63 but not CD9, CD29, and CD31. PMPs induced interleukin-8 (IL-8), interleukin-1 beta (IL-1 beta), and tumor necrosis factor alpha (TNF alpha) production by THP-1. PMPs also induced IL-8, IL-1 beta, and interleukin-6 (IL-6) production by ECs. Production was time-dependent. With RT-PCR, some cytokine mRNAs were detected in THP-1 and ECs after PMP stimulation. In relation to adhesiveness after PMP stimulation, we could clearly observe a shift in distribution not only of CD11b in THP-1 cells but also of CD54 in ECs. In addition, anti-P-selectin glycoprotein ligand-1 antibody reduced the expression of CD11b, CD32, and CD33 in THP-1 after PMP stimulation. These results suggest that high-shear-induced microparticles may contribute to the development of atherosclerosis and participate in vascular damage in inflammatory disorders.
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PMID:High-shear-stress-induced activation of platelets and microparticles enhances expression of cell adhesion molecules in THP-1 and endothelial cells. 1158 5

Complement plays an essential role in inflammation and tissue damage. However, it is largely unknown to what extent the system acts as a primary inducer of secondary mediator systems in the inflammatory network of human whole blood. Here we describe a novel in vitro model using the thrombin-specific hirudin analog lepirudin as anticoagulant, which, in contrast to heparin, did not interfere with complement activation. The model was used to study the role of complement in Escherichia coli-induced inflammatory responses. Granulocyte and monocyte oxidative burst was complement dependent as it was reduced by 85% and 70%, respectively, by the C3 [corrected] binding peptide compstatin. A similar reduction was found by inhibition of C5, C5a, and C5a receptor (C5aR). Furthermore, anti-CR3 antibodies were as efficient as the C5aR antagonist in reducing granulocyte oxidative burst, whereas blocking CD14 or C3aR had no effect. Up-regulation of granulocyte CR3 was virtually abolished by a C5aR antagonist. Opsonization and phagocytosis was completely inhibited by blocking of C5aR or CR3, whereas blocking of the FcgammaRs (CD16, CD32, CD64) had no effect. In contrast to oxidative burst and phagocytosis, cytokine secretion was largely complement independent. Thus, anti-CD14 abolished tumor necrosis factor-alpha, interleukin-6 (IL-6), and IL-10 secretion, whereas IL-8 was equally inhibited by anti-CD14 and compstatin. In conclusion, the present model is particularly useful for studying complement as part of the inflammatory network. The results emphasize a crucial role for C5a-C5aR interaction in E coli-induced up-regulation of CR3 and the subsequent oxidative burst and phagocytosis. Complement inhibition may have therapeutic implications in oxidative burst-induced tissue damage.
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PMID:Essential role of the C5a receptor in E coli-induced oxidative burst and phagocytosis revealed by a novel lepirudin-based human whole blood model of inflammation. 1217 11

C-reactive protein (CRP), a characteristic inflammatory marker, is a powerful predictor of cardiovascular events. Recent data suggest that CRP may also promote atherogenesis through inducing endothelial dysfunction. Lectin-like oxidized low-density lipoprotein (oxLDL) receptor-1 (LOX-1) is a newly identified endothelial receptor for oxLDL that plays a pivotal role in oxLDL-induced endothelial dysfunction. Whether CRP may regulate endothelial LOX-1 and induce endothelial dysfunction through this receptor is unknown. In the present study, we studied the in vitro effect of CRP on LOX-1 expression in human aortic endothelial cells (HAECs) and the role of LOX-1 in CRP-induced human monocyte adhesion to endothelium and oxLDL uptake by endothelial cells. Incubation of HAECs with CRP enhanced, in a dose- and time-dependent manner, LOX-1 mRNA and protein levels. Induction of LOX-1 protein was already present at 5 microg/mL CRP and reached a maximum at 25 microg/mL. This effect was reduced by antibodies against CD32/CD64, endothelin-1 (ET-1) and interleukin-6 (IL-6). The extent of stimulation of LOX-1 achieved by CRP was comparable to that elicited by high glucose and IL-6 and remained unchanged in presence of these factors. Finally, CRP increased, through LOX-1, both human monocyte adhesion to endothelial cells and oxLDL uptake by these cells. We conclude that CRP enhances endothelial LOX-1 expression and propose a new mechanism by which CRP may promote endothelial dysfunction, that of inducing LOX-1.
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PMID:C-reactive protein enhances LOX-1 expression in human aortic endothelial cells: relevance of LOX-1 to C-reactive protein-induced endothelial dysfunction. 1547 20

Yellow fever (YF) vaccines (17D-204 and 17DD) are well tolerated and cause very low rates of severe adverse events (YEL-SAE), such as serious allergic reactions, neurotropic adverse diseases (YEL-AND), and viscerotropic diseases (YEL-AVD). Viral and host factors have been postulated to explain the basis of YEL-SAE. However, the mechanisms underlying the occurrence of YEL-SAE remain unknown. The present report provides a detailed immunological analysis of a 23-year-old female patient. The patient developed a suspected case of severe YEL-AVD with encephalitis, as well as with pancreatitis and myositis, following receipt of a 17D-204 YF vaccination. The patient exhibited a decreased level of expression of Fc-gammaR in monocytes (CD16, CD32, and CD64), along with increased levels of NK T cells (an increased CD3(+) CD16(+/-) CD56(+/-)/CD3(+) ratio), activated T cells (CD4(+) and CD8(+) cells), and B lymphocytes. Enhanced levels of plasmatic cytokines (interleukin-6 [IL-6], IL-17, IL-4, IL-5, and IL-10) as well as an exacerbated ex vivo intracytoplasmic cytokine pattern, mainly observed within NK cells (gamma interferon positive [IFN-gamma(+)], tumor necrosis factor alpha positive [TNF-alpha(+)], and IL-4 positive [IL-4(+)]), CD8(+) T cells (IL-4(+) and IL-5(+)), and B lymphocytes (TNF-alpha(+), IL-4(+), and IL-10(+)). The analysis of CD4(+) T cells revealed a complex profile that consisted of an increased frequency of IL-12(+) and IFN-gamma(+) cells and a decreased percentage of TNF-alpha(+), IL-4(+), and IL-5(+) cells. Depressed cytokine synthesis was observed in monocytes (TNF-alpha(+)) following the provision of antigenic stimuli in vitro. These results support the hypothesis that a strong adaptive response and abnormalities in the innate immune system may be involved in the establishment of YEL-AND and YEL-AVD.
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PMID:Clinical and immunological insights on severe, adverse neurotropic and viscerotropic disease following 17D yellow fever vaccination. 1990 94

C-reactive protein (CRP) has emerged as a new marker for cardiovascular diseases. Activation of peroxisome proliferator-activated receptor delta (PPARdelta) plays beneficial roles in cardiac disorders. However, the relationship between CRP and PPARdelta in cardiac cells remains unclear. This study focused on the underlying molecular mechanisms of CRP and PPARdeltaagonists. Cardiomyocytes and cardiomyoblast cell line (H9c2) were used in different groups: Untreated; 15 microg/ml CRP with or without 1 microM PPARdelta agonists (L-165041). CRP increased PPARdelta and interleukin-6 expression in cardiomyocytes and H9c2 cardiomyoblasts. NF-kappaB inducing kinase (NIK) and NF-kappaB pathway also activated by CRP stimulation. These changes could be inhibited by L-165041 through p38MAPK and c-JNK pathways. However, transfection with siRNA of CD32 CRP receptor did not decrease CRP signaling or reverse the effects of L-165041 in CRP-treated cardiomyocytes and H9c2. Pretreatment with L-165041 attenuated apoptosis induced by hypoxia with or without CRP in H9c2 cardiomyoblasts. CRP up-regulated PPARdelta expression in cardiomyocytes and H9c2. L-165041 attenuated CRP-induced pro-inflammatory signaling through p38MAPK and c-JNK in H9c2 cardiomyoblasts. However, PPARdelta activation attenuated CRP-induced NF-kappaB pathway may be independent of CD32. These results may provide new evidence of PPARdelta beneficial effects for inflammatory cardiomyopathy.
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PMID:Peroxisome proliferator-activated receptor delta agonists attenuated the C-reactive protein-induced pro-inflammation in cardiomyocytes and H9c2 cardiomyoblasts. 2059 14