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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The bone marrow microenvironment consists of stromal cells and extracellular matrix components which act in concert to regulate the growth and differentiation of hematopoietic stem cells. There is little understanding of the mechanisms which modulate the regulatory role of stromal cells. This study examined the hypothesis that mesenchymal growth factors such as basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) modulate stromal cell activities and thereby influence the course of hematopoiesis. Both bFGF and EGF were potent mitogens for marrow stroma. However, both factors proved to be inhibitory to hematopoiesis in primary long-term marrow cultures. Inhibition was also observed when hematopoietic cells and bFGF or EGF were added to subconfluent irradiated stromal layers, demonstrating that the decline of hematopoiesis was not due to overgrowth of the stromal layer. Loss of hematopoietic support in bFGF and EGF was dose-dependent. Removal of bFGF and EGF permitted stromal layers to regain their normal capacity to support hematopoiesis. In stroma-free long-term cultures, neither factor affected CFU-GM expansion. Basic FGF slightly enhanced granulocyte-macrophage colony forming unit (CFU-GM) cloning efficiency in short-term agarose culture. Basic FGF did not reduce the levels of interleukin-6 (IL-6), GM-CSF, or G-CSF released by steady state or IL-1-stimulated stroma. Similarly, the constitutive levels of steel factor (SF) mRNA and protein were not affected by bFGF. Basic FGF did not alter the level of TGF-beta 1 in stromal cultures. We conclude that bFGF and EGF can act as indirect negative modulators of hematopoietic growth in stromal cultures. The actual mediators of regulation, whether bound or soluble, remain to be identified.
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PMID:Basic fibroblast growth factor and epidermal growth factor downmodulate the growth of hematopoietic cells in long-term stromal cultures. 759 17

Interactions of the conceptus with the immune system can involve either anti-sperm or anti-conceptus immune responses that limit the success of pregnancy of beneficial effects of cytokines released from lymphoid cells on embryonic growth and gene expression. The immune system is functional in the uterus and therefore there is the potential for anti-conceptus immune responses. However, endometrial lymphocytes are distinct in many respects from lymphoid cells at peripheral sites; one major subpopulation expresses the gamma delta T-cell receptor and may not recognize major histocompatibility antigens. There are also several control systems to limit anti-conceptus immune responses. In particular, expression of major histocompatibility antigens on the trophoblast is either absent or of limited distribution. In addition, activation of anti-conceptus immune responses leading to cytolytic responses is further limited by the presence of molecules that can inhibit lymphocyte transformation. The most well-characterized of these are prostaglandin E2 from placental and endometrial tissues, interferon-tau from the trophoblast during early pregnancy, and two endometrial proteins called the uterine milk proteins (UTMP). Progesterone plays a central role in inhibition of immune responses in actions that are mediated at least in part through endometrial secretion of UTMP. Cytokines play important roles as autocrine and paracrine regulators in many tissues including the reproductive tract. In ruminants, the best described example is interferon-tau. Other cytokines found in the reproductive tract or produced by the conceptus include interleukin-1, leukaemia inhibitory factor, granulocyte-macrophage colony stimulating factor and interleukin-6. It is possible that the major source of cytokines in the reproductive tract is non-lymphoid cells of the endometrium and trophoblast. It is not known to what extent endometrial lymphocytes contribute to the cytokine milieu because no cytokine has been identified as a product of endometrial lymphocytes. However, there is a population of granulated lymphocytes that increase in number and granularity in the luminal epithelium of the late-pregnant ewe that is a potential source of cytokines.
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PMID:Interactions between the immune system and the ruminant conceptus. 762 50

Human peripheral blood granulocytes were analyzed for expression of interleukin-6 (IL-6) using reverse-transcriptase polymerase chain reaction (RT-PCR) and in situ hybridization. Neutrophil granulocytes from healthy donors were shown to express variable levels of IL-6. This expression was rapidly down-regulated after the removal of the cells from the circulating blood. In vitro culture of neutrophils abolished IL-6 expression, which could be reactivated by addition of GM-CSF to the culture medium. Constitutive expression of IL-6 was instead demonstrated in eosinophil granulocytes purified from normal donors and from a hypereosinophilic patient. In situ hybridization of unstimulated granulocytes confirmed that IL-6 expression occurs both in eosinophils and in neutrophils from peripheral blood. These findings show that granulocytes can actively contribute to cytokine expression in the peripheral blood and suggest their role in the afferent limb of the immune response, since by IL-6 production they might modulate T- and B-lymphocyte functions, granulocyte self-priming, and endothelial interaction.
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PMID:Interleukin-6 expression in human neutrophil and eosinophil peripheral blood granulocytes. 768 28

The synthesis and release of parathyroid hormone-related protein (PTHrP) could be influenced in a paracrine or autocrine manner by substances present around or inside tumours, such as bone or stromal cell-derived cytokines, factors produced by the tumour itself or by peritumoural inflammatory cells. We investigated the effects of various cytokines known to be synthesized by osteoblasts, stromal cells, leucocytes or cancer cells, on PTHrP production by the human lung squamous cell carcinoma line BEN. The influence of tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) was studied, and compared with those of insulin-like growth factors-I and -II (IGF-I, IGF-II), or macrophage- or granulocyte-macrophage colony-stimulating factors (M-CSF, GM-CSF). TNF-alpha caused a 1.9 +/- 0.1-fold increase in immunoreactive PTHrP production, which was maximal by 24 h of incubation. IL-6 caused a 2.3 +/- 0.2-fold increase, which was maximal by 16 h. These effects, which were time- and concentration-dependent, were blocked by monoclonal antibodies raised against the corresponding cytokine. An increase of PTHrP mRNA was found in IL-6-treated cells. IGF-I and IGF-II increased PTHrP production by 2.0 +/- 0.3- and 2.3 +/- 0.1-fold respectively. Neither M-CSF nor GM-CSF altered PTHrP production up to 64 h of incubation. PTHrP production was not affected by varying extracellular calcium concentrations, but was decreased by incubation with 100 nmol/l dexamethasone.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of parathyroid hormone-related protein production in a human lung squamous cell carcinoma line. 782 96

Twenty-seven patients with advanced adenocarcinoma were studied. Groups of three patients received interleukin-6 (IL-6) in doses ranging from 0.5 to 20 micrograms/kg by daily subcutaneous injection on days 1-7 and 22-49. Four patients received IL-6 2.5 micrograms/kg/d with GM-CSF 5 micrograms/kg/d and three patients received IL-6 2.5 micrograms/kg/d with IL-3 5 micrograms/kg/d. Circulating platelet numbers increased 1.65-fold during IL-6 treatment, in a dose-dependent fashion (P = 0.01). This increase is inferior to that expected from laboratory studies. No significant change in total WBC was seen after IL-6 alone. After treatment with IL-6, significant increases in numbers of circulating mononuclear cells (2.2-fold, P = 0.006) and GM-CFC numbers (3.2-fold, P = 0.01) were seen, but there were no changes in circulating megakaryocyte-CFC numbers. In contrast, after treatment with IL-6 and GM-CSF, larger increases in both circulating GM-CFC (20-fold, P = 0.04) and megakaryocyte-CFC numbers (18-fold, P = 0.03) were seen. Increases in blood progenitors after treatment with IL-6 and IL-3 did not achieve statistical significance. The ability of peripheral blood mononuclear cells to generate and sustain long-term haemopoiesis in vitro was similar in IL-6-treated patients to that in untreated control subjects. No significant changes in the incidence of bone marrow progenitors or their cycling status (assessed by thymidine suicide) were seen. These data suggest that IL-6 alone will not be clinically useful to mobilize blood progenitor cells in cancer patients.
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PMID:Effects of interleukin-6 on mobilization of primitive haemopoietic cells into the circulation. 787 72

Organisms belonging to the Mycobacterium avium complex (MAC) are common pathogens in immunosuppressed and AIDS patients. This paper reviews the role of cytokines in the pathogenesis of MAC infection. MAC organisms mainly infect monocytes and macrophages, and the effect of HIV infection on susceptibility of macrophages to MAC infection is largely unknown. Both GM-CSF and tumour necrosis factor-alpha can induce mycobacteriostatic/mycobactericidal activity in MAC-infected macrophages. The activity of interferon-gamma on mycobacterial infection appears to be dependent on the type of macrophage: in murine peritoneal and human monocyte-derived macrophages, interferon-gamma does not inhibit the intracellular growth of MAC, whereas in intestinal macrophages interferon-gamma results in inhibition of MAC. Transforming growth factor-beta 1, interleukin-10 and interleukin-6 have all been shown to counteract the immunoactivating cytokines and MAC survival may be due to induction of these inhibitory cytokines within the macrophage. GM-CSF has been given to patients with disseminated MAC infection. Isolated macrophages from these patients demonstrated increased superoxide anion production and enhanced mycobacteriostatic/cidal activity compared with macrophages isolated from the same patients before GM-CSF treatment. These results suggest that GM-CSF may have potential in the treatment of MAC infection.
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PMID:Potential role of cytokines in disseminated mycobacterial infections. 787 49

Haemopoiesis is often depressed in patients suffering from acquired immune deficiency syndrome (AIDS). Although several mechanisms have been postulated to be responsible for depressed haemopoiesis in AIDS patients, the aetiology of this disorder is still unknown. We hypothesized that failure of the stromal microenvironment may account for part of the haemopoietic defect observed in patients with AIDS. We therefore studied a murine model of AIDS (MAIDS) caused by infection with LP-BM5 virus to determine the ability of bone marrow cells from immunodeficient mice to establish long-term stromal cultures. In addition, normal and MAIDS mice received AZT (2 mg/ml) in their drinking water for up to 1 month to determine the effects of AZT treatment in vivo on the ability of bone marrow cells to support haemopoiesis in long-term cultures. Decreased numbers of non-adherent cells were observed in long-term bone marrow cultures (LTBMC) of MAIDS mice when compared to cultures derived from normal mice. Decreased numbers of non-adherent cells were observed in cultures of bone marrow cells from AZT-treated normal mice, when compared to untreated normal controls. Cells from AZT-treated MAIDS mice produced the smallest number of non-adherent cells. BFU-E and CFU-G/M were decreased in cultures of MAIDS mice when compared to those of normal mice. AZT-treatment further decreased the number of colony-forming cells in both MAIDS mice and normal cultures. Stromal cell function of MAIDS mice was also assessed by inoculating non-adherent cells from normal mice onto confluent irradiated MAIDS LTBMC. Stroma from MAIDS mice was unable to support haemopoietic function of normal bone marrow cells. Polymerase chain reaction (PCR) analysis of steady state levels of cytokine mRNAs of cells from confluent cultures revealed that levels of interleukin-6 mRNA were unchanged in MAIDS mice, as compared to normal controls, but the levels of GM-CSF were decreased in MAIDS mice. These data suggest that LP-BM5 MuLV infection alters the functioning of the haemopoietic stroma and that one mechanism of this depression in haemopoiesis may be via alterations of cytokine production.
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PMID:Impaired ability of bone marrow cells from immunodeficient mice to establish long-term cultures. 791 27

We have extracted and purified Yersinia enterocolitica ATCC 9610 porins that have molecular weights of 36-38 kDa. They inhibited phagocytosis and phagosome-lysosome fusion (30%) in human monocytes and caused enhanced nitrite production. Preincubation of polymorphonuclear neutrophils with porins (1-10 micrograms/ml/10(6) cells) induced a reduction in chemotaxis, adherence to nylon wool and chemiluminescence. Human lymphomonocytes treated with Y. enterocolitica porins showed a distinctive cytokine profile. Interleukin-1 alpha, interleukin-6 and tumour necrosis factor alpha were released within 3-6 h, while interleukin-8, gamma interferon and granulocyte-macrophage colony stimulating factor were released after 18 h. Interleukin-3 and interleukin-4 were not detected at up to 48 h of incubation. In conclusion, these immunomodulating and histotropic properties may account for Y. enterocolitica infection and its sequelae.
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PMID:Properties of Yersinia enterocolitica porins: interference with biological functions of phagocytes, nitric oxide production and selective cytokine release. 799 43

Human interleukin-11 (IL-11) is a cytokine with a broad spectrum of activity, similar to interleukin-6 (IL-6). However, its role in human disease is poorly understood, partly because of a lack of sensitive bioassays. A subclone (B9-11) obtained from the B9 hybridoma (which responds poorly to human IL-11) enabled us to develop a highly sensitive bioassay for human IL-11. B9-11 cells responded only to human IL-11 and IL-6 and not to other human cytokines using the same gp130 transducer chain (ciliary neurotrophic factor, leukemia inhibitory factor and oncostatin M) or to other human interleukins (interleukin-1 to interleukin-13), human hematopoietic cytokines (granulocyte colony stimulating factor, granulocyte-macrophage colony stimulating factor, colony stimulating factor-1) and various other human cytokines (interferon-alpha, tumor necrosis factor-alpha, tumor necrosis factor-beta, fibroblast growth factor and nerve growth factor). In addition, these cytokines did not interfere with the IL-11 response of B9-11 cells. IL-11-induced proliferation of B9-11 cells was unaffected by anti-murine IL-6 receptor mAb but inhibited by anti-gp130 mAb. Half-maximal proliferation of B9-11 cells was obtained with 30 pg/ml of recombinant IL-11, a concentration 300-fold lower than IL-11 concentrations known to be active on human cells. Finally, culturing of B9-11 cells with an anti-IL-6 mAb enabled us to measure the natural IL-11 produced by various cell lines. Thus, B9-11 cells should be useful for studies of IL-11 involvement in various human diseases as well as for a better understanding of the mechanisms of action of this cytokine.
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PMID:A highly sensitive quantitative bioassay for human interleukin-11. 803 82

Differentiation of the U937 cell line can be induced by various agents. We have investigated the differentiation abilities of gamma-interferon (IFN-gamma), interleukin-6 (IL-6), macrophage and granulocyte-macrophage colony-stimulating factors (M-CSF + GM-CSF) or the combinations IL-6 + M-CSF + GM-CSF and IFN-gamma + M-CSF + GM-CSF on the U937 cells by studying the morphology, cytochemical activity and several functional properties. The expression of the Leu-CAM proteins (CD11a, CD11b, CD11c, CD18) was also evaluated during the culture period. Our results show that the cytokines used in this study inhibit to a certain extent the proliferation of the tumor cells and drive the cells toward a differentiation phenotype that has several characteristics in common with mononuclear phagocytes, such as the expression of CD14, phagocytosis and release of superoxide anions. The adhesion molecules CD11b alpha chain and CD18 beta chain were strongly induced on the U937 cells with a maximal expression of the CD11b on the cells cultured with either M-CSF + GM-CSF or the combinations of IL-6 and IFN-gamma with M-CSF + GM-CSF. Conversely, for CD11a and CD11c alpha chains a rather low enhancement of the expression was noticed. In our culture system, cells incubated with the combination of M-CSF + GM-CSF exhibited differentiation characteristics which appeared to be largely potentialized when cytokines such as IL-6 or IFN-gamma were added.
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PMID:U937 cell line: impact of CSFs, IL-6 and IFN-gamma on the differentiation and the Leu-CAM proteins expression. 809 63


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