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Query: UNIPROT:P04141 (granulocyte-macrophage colony-stimulating factor)
 6,790 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanisms that regulate the mRNA levels of interleukin-5 (IL-5) were compared with those regulating the mRNA levels of two other coordinately expressed lymphokines in the murine T lymphoma EL4.23. Our results indicate that IL-5 mRNA levels are independently regulated from those of IL-2 and granulocyte-macrophage colony-stimulating factor (GM-CSF) mRNAs. The induction of IL-5 mRNA by phorbol 12-myristate 13-acetate (PMA) stimulation was found to be cyclosporin A-resistant, in contrast to the induction of IL-2 and GM-CSF mRNAs. Although the three lymphokine mRNAs were not detected in unstimulated cells by Northern blot analysis, the GM-CSF gene was found by nuclear run-off analysis to be constitutively transcribed. However, the IL-2 and IL-5 genes were transcriptionally inactive in the absence of PMA stimulation. The induction of IL-5 mRNA by PMA stimulation primarily involved increased transcriptional activity. In contrast, GM-CSF mRNA induction predominantly involved enhanced mRNA stability. Both transcriptional and mRNA stabilization mechanisms appeared to regulate IL-2 mRNA induction. The activation of IL-2 and IL-5 gene transcription was dependent on de novo protein synthesis. Cellular treatment with cycloheximide enhanced IL-2 gene transcription once activation was initiated, implicating the involvement of a labile repressor(s). Furthermore, IL-5 mRNA was more stable than IL-2 and GM-CSF mRNAs. These latter two species were stabilized by cycloheximide, suggesting that a labile mechanism may regulate their degradation.
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PMID:Mechanisms regulating the mRNA levels of interleukin-5 and two other coordinately expressed lymphokines in the murine T lymphoma EL4.23. 820 86

In this study, we demonstrate that mononuclear cells of human milk have a potential for production of many different cytokines. We applied a technique for cytokine detection at the single-cell level using cytokine specific MAb and immunofluorescence. The characteristic staining pattern obtained represents intracellular cytokine production, which allows for the assessment of the cellular origin of production. Milk mononuclear cells were mitogen-stimulated in vitro and cultured for 4 h and then stained for 13 cytokines. Lipopolysaccharide stimulation induced extensive production of the following monokines: IL-1 alpha, IL-1 beta, IL-1ra, IL-6, IL-8, and tumor necrosis factor-alpha. IL-10 and granulocyte-macrophage colony-stimulating factor were smaller products, although detectable in most samples. The abundant monokine production correlated with the high number of macrophages in milk. Spontaneous monokine production in unstimulated cells could be detected in six out of 11 samples. The highest incidence was evident for IL-8. No spontaneous lymphokine production was detected. Considering the low proportion of lymphocytes, stimulation with phorbol myristate acetate in combination with ionomycin resulted in considerable production of the following lymphokines: IL-2, IL-3, IL-4, IL-10, interferon-gamma, tumor necrosis factor-alpha. Macrophages contributed to the high production of tumor necrosis factor-alpha and GM-CSF. IL-5 synthesis was detectable in only one sample. This work reveals that human milk mononuclear cells are potent producers of cytokines when mitogen stimulated in vitro. The in vivo implications of these findings remain to be investigated further.
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PMID:Cytokine production in mononuclear cells of human milk studied at the single-cell level. 823 27

The degradation of some proto-oncogene and lymphokine mRNAs is controlled in part by an AU-rich element (ARE) in the 3' untranslated region. It was shown previously (G. Brewer, Mol. Cell. Biol. 11:2460-2466, 1991) that two polypeptides (37 and 40 kDa) copurified with fractions of a 130,000 x g postribosomal supernatant (S130) from K562 cells that selectively accelerated degradation of c-myc mRNA in a cell-free decay system. These polypeptides bound specifically to the c-myc and granulocyte-macrophage colony-stimulating factor 3' UTRs, suggesting they are in part responsible for selective mRNA degradation. In the present work, we have purified the RNA-binding component of this mRNA degradation activity, which we refer to as AUF1. Using antisera specific for these polypeptides, we demonstrate that the 37- and 40-kDa polypeptides are immunologically cross-reactive and that both polypeptides are phosphorylated and can be found in a complex(s) with other polypeptides. Immunologically related polypeptides are found in both the nucleus and the cytoplasm. The antibodies were also used to clone a cDNA for the 37-kDa polypeptide. This cDNA contains an open reading frame predicted to produce a protein with several features, including two RNA recognition motifs and domains that potentially mediate protein-protein interactions. These results provide further support for a role of this protein in mediating ARE-directed mRNA degradation.
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PMID:Purification, characterization, and cDNA cloning of an AU-rich element RNA-binding protein, AUF1. 824 82

Phorbol myristate acetate (PMA) treatment of an EL-4 thymoma cell line (EL-4FARRAR) induced secretion of a factor that inhibited intracellular killing of Leishmania major amastigotes by activated macrophages. Analysis of the cytokines produced by EL-4 cells after PMA stimulation identified interleukin-2 (IL-2, 2500 U/ml), IL-4 (1280 U/ml), interferon-gamma (IFN-gamma; 100 U/ml), and granulocyte-macrophage colony-stimulating factor (GM-CSF; 50 U/ml). Neither tumor necrosis factor nor transforming growth factor beta (TGF-beta) was detected. Each of the cytokines present in EL-4 fluids was assessed for capacity to activate macrophages for destruction of parasites or to suppress intracellular killing. IFN-gamma and GM-CSF both activated macrophages to kill Leishmania; IL-2 and IL-4 had no activity for induction of this antimicrobial effector function. IL-2 and IL-4 were tested for their capacity to inhibit lymphokine- or IFN-gamma-induced destruction of L. major by macrophages: IL-4 was ineffective, but IL-2 markedly suppressed the activation of macrophages for intracellular killing. Addition of > or = 10 U/ml of IL-2 at the time of infection, or up to 4 h before, blocked up to 100% of the capacity of activated macrophages to kill intracellular amastigotes. Immunoaffinity treatment of EL-4 fluids with anti-IL-2 antibody resulted in > 80% reduction in suppression of intracellular killing. The suppressive effects of IL-2 were not direct, but mediated by TGF-beta. IL-2 induced resident peritoneal macrophages to secrete > 5000 pg/ml TGF-beta 1, a quantity that is > 500-fold higher than constitutive background levels (20-40 pg/ml) and is sufficient to block intracellular killing activities. This increase in secretion of TGF-beta was not dependent increases in TGF-beta 1 mRNA. Treatment of cultures with EL-4 fluids or recombinant IL-2 in the presence of antibody to TGF-beta 1 blocked the suppressive activity of both. Thus, IL-2 was the major suppressor factor in EL-4 fluids, and it acted indirectly through the induction and autocrine action of TGF-beta.
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PMID:Interleukin-2 suppresses activated macrophage intracellular killing activity by inducing macrophages to secrete TGF-beta. 828 43

Interferon-gamma (IFN-gamma), a lymphokine produced by lymphocytes with the help of monocytes, is essential for host resistance to intracellular pathogens. Leukocytes from normal term newborn infants cannot produce IFN-gamma in vitro in response to stimulation by antigen or mitogens in vitro or in vivo. We investigated the production of IFN-gamma in vitro using endotoxin from Salmonella typhimurium as a stimulus. In contrast to those from adults, mononuclear cells derived from the cord blood of newborn infants did not produce IFN-gamma in response to this endotoxin. We investigated the contribution of the functional immaturity of cord blood monocytes to this relative inability to produce IFN-gamma. Aging of the monocytes for 2 weeks in vitro or treatment of freshly isolated cord blood monocytes with conditioned medium (from cultures of mononuclear cells from healthy adults) greatly enhanced IFN-gamma production stimulated by endotoxin. Furthermore, recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF), or IFN-gamma was able to substitute in part for the conditioned medium from adult cells. Thus correction of the functional immaturity of monocytes derived from newborn infants can result in enhanced production of IFN-gamma in vitro.
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PMID:Enhancement in vitro of the low interferon-gamma production of leukocytes from human newborn infants. 831 52

Attempts have been made to isolate continuous lines of rare subsets of lymphoid cells present in murine spleen in order to analyse their function and lineage relationship with respect to other lymphoid cells. Mitogenic stimulation was used to expand the lymphoid cells remaining in spleen following depletion of CD4+ and CD8+ T cells by antibody and complement treatment. Cells were cultured in the presence of concanavalin A (Con A), interleukin-2 (IL-2) and syngeneic irradiated spleen feeder cells. This procedure expanded a population of non-T-, non-B-lymphoid cells bearing a common, unique phenotype resembling lymphoid precursors. Eight cloned lines from B10.A(2R) and B10.A(5R) strains of mice have been analysed here. Analysis of cell surface marker expression has revealed positive expression of class I and class II major histocompatibility complex (MHC) antigens, CD44, CD45 (T200 and B220) but expressing no markers unique to T, B or myeloid cells. All cell lines represent agranular lymphoblasts and show no evidence of early T-cell receptor (TcR) or Ig heavy chain gene rearrangements, suggesting no commitment to T-or B-lymphoid lineage. Despite expression of the NK1.1 marker for natural killer (NK) cells, none of the cell lines has been shown to have cytotoxic function for NK targets, nor could cytotoxic function be induced following various activation procedures. Analysis of lymphokine production has revealed no detectable IL-1, IL-2, IL-3, IL-4, IL-5, tumour necrosis factor-alpha (TNF-alpha) or granulocyte-macrophage colony-stimulating factor (GM-CSF) in cell supernatants. However, all but one of these cell lines constitutively produce IL-6. Each cell line has been shown to induce T-cell proliferation independently in mixed lymphocyte reactions, implicating the capacity of these cells to act as antigen-presenting cells. Consistent with this hypothesis is the observation that these cells also demonstrate endocytic activity for foreign proteins. This was visualized by their uptake of fluoresceinated albumin into cytoplasmic granules. Since they express many cell surface markers common to described isolates of spleen dendritic cells, including both class I and class II major histocompatibility molecules, they would appear to represent the first example of continuous lines of this rare cell subset.
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PMID:Characterization of unique lymphoid cells derived from murine spleen which constitutively produce interleukin-6. 834 1

Cloned T lymphocytes (TLC) of the CD4+CD8- phenotype established from peripheral blood of a patient with idiopathic hypereosinophilic syndrome (HES) were found to release a lineage-specific eosinophilic colony-stimulating factor (Eo-CSF). The present study was undertaken to identify the lymphokine accounting for this Eo-CSF activity. Comparison of TLC-derived Eo-CSF with recombinant human interleukin-5 (rhIL-5), recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) and recombinant human interleukin-3 (rhIL-3) by in vitro clonogenic assays revealed similar bioactivity of HES-derived Eo-CSF and IL-5. Neutralization studies using specific antibodies against IL-5, GM-CSF and IL-3 confirmed that IL-5 mainly accounts for the Eo-CSF activity in all 9 HES-derived TLC tested. Eosinophilic colony (CFU-Eo) formation supported by conditioned media of the TLC was significantly inhibited in all clones by addition of anti-IL-5 monoclonal antibody (MAB) to the conditioned media. Inhibition by anti-IL-5 MAB was specific and dose-dependent. In 2 of the 9 clones, anti-GM-CSF antibodies could partially neutralize the Eo-CSF activity in the conditioned media. In 4 clones, addition of a combination of anti-IL-5 MAB and anti-GM-CSF antiserum to the conditioned media reduced CFU-Eo formation significantly more than addition of anti-IL-5 MAB alone. In none of the TLC could a significant role for IL-3 in eosinophilic colony formation be shown. These results were confirmed at the mRNA level. Cytokine transcripts were detected by reverse transcription (RT) and subsequent polymerase chain reaction (PCR). Under the same experimental conditions, all HES-derived TLC, but only one third of tested TLC from healthy donors, expressed IL-5 mRNA 5 days after stimulation. In control TLC with inducible IL-5 mRNA expression, IL-5 transcripts were found for only 3 days after stimulation. In contrast, HES-derived TLC contained IL-5 mRNA at least until day 18 after restimulation. All HES clones expressed GM-CSF mRNA upon stimulation. Two HES-derived TLC were found to lack IL-3 mRNA even after stimulation. Whereas IL-5 was expressed abundantly in all HES-clones, the intensity of PCR products for GM-CSF and IL-3 showed striking differences. Our in vitro results suggest that IL-5 produced by activated CD4+ T lymphocytes plays a crucial role in the induction of eosinophilia in HES. In addition, GM-CSF but not IL-3 seems to contribute partially to the increased eosinophil production in HES.
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PMID:Interleukin-5 is the predominant eosinophilopoietin produced by cloned T lymphocytes in hypereosinophilic syndrome. 842 73

We studied the regulatory effects of various cytokines on the susceptibility to lymphocyte-mediated lysis of cell lines established from patients with acute T-lymphoblastic leukemia (T-ALL). None of the cytokines tested affected the sensitivity of these targets to natural killer activity. In contrast, specific cytokines, different for each cell line, enhanced the susceptibility to lymphokine-activated killer (LAK) cells, while interferon gamma (IFN)-gamma always induced resistance. The same cytokines that increased LAK susceptibility also induced proliferative responses. The TALL-101 cell line, which responded to granulocyte-macrophage colony-stimulating factor (GM-CSF) with increased susceptibility to lysis, and to IFN-gamma with resistance, was used as a model to analyze the mechanisms underlying these changes. Cold target inhibition and conjugate formation assays both indicated that the changes in LAK susceptibility were not at the level of effector-target (E/T) binding. Furthermore, no significant changes in surface expression of adhesion molecules involved in E/T binding were induced by either GM-CSF or IFN-gamma on TALL-101 cells. Finally, N-alpha-benzyloxycarbonyl-L-lysine thiobenzyl-esterase assays demonstrated no differences in the ability of these cytokines to trigger the secretion of cytolysins in the bound effectors compared to unstimulated cells. Taken together, these results suggest that the cytokine-modulated susceptibility to lysis of these T-ALL lines might occur at a post-binding stage with mechanisms involving an altered responsiveness to lytic factors.
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PMID:Cytokine modulation of the susceptibility of acute T-lymphoblastic leukemia cell lines to LAK activity. 844 46

The synthesis and role of several lymphokines were examined during contact sensitization to oxazolone (OX). Application of OX to the skin of mice increased the delayed-type hypersensitivity (DTH) response to challenge, serum titres of OX-specific IgG1 and IgG2a, and draining lymph node cell (LNC) numbers. At day 3, LN contained detectable interleukin-4 (IL-4), interferon-gamma (IFN-gamma) and granulocyte-macrophage colony-stimulating factor (GM-CSF) but not IL-2 or IL-3 mRNAs; IL-3 and higher levels of IL-4, IFN-gamma and GM-CSF mRNAs were measured after 24 hr culture with anti-CD3 antibody in OX-primed but not unprimed LNC. As a result of sensitization, LNC secreted IL-3 constitutively and produced elevated levels of IL-2, IL-3, IL-4 and IFN-gamma in response to anti-CD3 antibody; a similar but weaker lymphokine response was recalled by OX-protein conjugate. CD4+ cells were the major source of the anti-CD3-induced lymphokines except IFN-gamma, which was derived mainly from CD8+ cells. Since both IL-4 and IFN-gamma were synthesized by OX-primed LNC in vivo and in vitro, their role was investigated by administering anti-lymphokine antibodies at the time of sensitization. Anti-IL-4 treatment reduced OX-specific serum IgG1 titres without affecting IgG2a titres, whereas anti-IFN-gamma treatment reduced IgG2a but not IgG1 titres. Although neither antibody altered DTH responsiveness, anti-IFN-gamma treatment markedly increased IL-4 production by CD4+ LNC and reduced IFN-gamma production in vitro, particularly by CD4+ cells. We conclude that endogenous IL-4 and IFN-gamma reciprocally influence the isotype of the Ig response to OX and that IFN-gamma also affects the relative levels of IL-4 and IFN-gamma synthesis by CD4+ LNC.
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PMID:Contact sensitization to oxazolone: involvement of both interferon-gamma and interleukin-4 in oxazolone-specific Ig and T-cell responses. 847 11

The treatment of cancer with lymphokine-activated killer (LAK) cells in conjunction with high-dose interleukin-2 (IL-2) has been limited by the toxicity of IL-2 and the narrow range of tumors that respond to therapy. Cytokines that are capable of augmenting lower doses of IL-2 are, therefore, a major focus of research. We report here that granulocyte-macrophage colony-stimulating factor (GM-CSF) can augment low-dose IL-2 LAK induction from murine splenocytes. Anti-tumor necrosis factor alpha (anti-TNF alpha) or anti-interferon gamma (anti-IFN gamma) monoclonal antibodies did not inhibit (IL-2 + GM-CSF)-induced LAK generation, indicating that GM-CSF augmentation does not require TNF alpha or IFN gamma activity. Depletion of natural killer cells before culture did not inhibit low-dose IL-2-induced LAK generation or the ability of GM-CSF to augment LAK generation. In contrast, depletion of both CD4+ and CD8+ T cells before culture inhibited the generation of LAK activity. However, depletion of only CD4+ T cells, or only CD8+ T cells, did not inhibit the generation of IL-2 or (IL-2 + GM-CSF) LAK activity. These results suggest that LAK precursors are present in both the CD4+ and CD8+ T-cell populations and suggest that the addition of GM-CSF to low-dose IL-2 may result in the generation of T-derived LAK cells.
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PMID:Effect of granulocyte-macrophage colony-stimulating factor on lymphokine-activated killer cell induction. 849 Jan 77


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