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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 effect of granulocyte-macrophage colony-stimulating factor (GM-CSF), a pluripotent cytokine, on tumoricidal activity of alveolar macrophages and monocytes from nonsmoking normal volunteers was compared using [3H]thymidine-labeled human tumor cells (SK-MEL-28, melanoma) as targets. A dose-response study (500-5000 units/ml) of recombinant GM-CSF indicated dramatic differences between cytotoxicity of alveolar macrophages and blood monocytes. Macrophages exhibited significant (P less than 0.01) tumoricidal activity at all GM-CSF doses tested. In contrast, monocytes showed no significant tumoricidal activity at 500 units/ml and significantly (P less than 0.01) less activity than alveolar macrophages at doses of 1000-5000 units/ml. Maximal activity in alveolar macrophages occurred 72-96 h after exposure to 1000-5000 units/ml GM-CSF. Tumoricidal activity may be related to the state of maturation, because monocytes matured in vitro for 7 days displayed enhanced tumoricidal activity after GM-CSF exposure. Tumor necrosis factor alpha and interleukin 1 beta were measured in supernatant fluids of 24-h GM-CSF-treated cells. No significant increase in either cytokine was detected after GM-CSF treatment of alveolar macrophages. Monocyte interleukin 1 beta secretion was not enhanced by GM-CSF; however, tumor necrosis factor alpha secretion was enhanced in some donors (three of five). Superoxide anion production of alveolar macrophages was not enhanced by GM-CSF. These data suggest that alveolar macrophage tumoricidal activity is induced by GM-CSF and is not dependent on oxidative metabolism or secreted forms of interleukin 1 beta or tumor necrosis factor alpha.
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PMID:Differential effect of recombinant granulocyte macrophage colony-stimulating factor on human monocytes and alveolar macrophages. 254 32

The addition of the platelet-activating factor (PAF) to neutrophils causes an increase in cytoskeletal actin, a rise in the intracellular concentration of free calcium, release of arachidonic acid, and the synthesis of PAF. The PAF synthesis in human neutrophils stimulated by PAF is greatly potentiated by the human granulocyte-macrophage colony-stimulating factor. Incubation of human neutrophils with the tumor copromoter phorbol 12-myristate 13-acetate (PMA) for 3 min prior to the addition of the stimulus inhibits all these responses produced by PAF. The inhibition is prevented when the cells are incubated with protein kinase C inhibitors such as 1-(5-isoquinolinesulfonyl)-2-methylpiperazine for 5 min prior to the addition of PMA. The rise in the intracellular concentration of free calcium in human neutrophils stimulated with leukotriene B4 is also inhibited by PMA, and this inhibition is prevented by protein kinase C inhibitors such as staurosporine. Unlike PMA, the inactive ester 4 alpha-phorbol 12,13-didecanoate has no inhibitory effect on the stimulated rise in the intracellular concentration of free calcium. The binding of either PAF or leukotriene B4 to intact cells is inhibited by PMA. The most important finding of the present studies is that PMA interferes with the binding of PAF and leukotriene B4 to their respective receptors. Whether PMA inhibits the binding of these lipid mediators by activating protein kinase C or by perturbing the membrane directly remains to be elucidated.
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PMID:Phorbol 12-myristate 13-acetate inhibits binding of leukotriene B4 and platelet-activating factor and the responses they induce in neutrophils: site of action. 254 88

Binding of radiolabeled human granulocyte-macrophage colony-stimulating factor (GM-CSF) was studied with blast cells from eight patients with acute myeloblastic leukemia (AML), and neoplastic lymphoid cells from one patient with acute lymphoblastic leukemia (ALL), two patients with chronic lymphocytic leukemia (CLL) and one patient with undiagnosed B cell neoplasia. In all AML cases studied, Scatchard graphs of the direct binding data were curvilinear, and were best fitted by curves derived from a two-binding-site model; one site with high affinity (Kd1 = 12-71 pM; 174-602 sites/cell) and the other with low affinity (Kd2 = 0.5-2.7 nM; 1137-6020 sites/cell). A cross-linking study on blast cells from one AML patient demonstrated specific bands which were similar to those reported for peripheral blood neutrophils. Furthermore, blast colony assays for the same preparations showed remarkable proliferative response to GM-CSF in the concentration range from 0.3 nM to 7.0 nM (ED50 greater than 0.7 nM). This concentration range is approximately one order of magnitude higher than that which is effective for colony formation from normal bone marrow progenitors (ED50 in equilibrium 0.1 nM). No significant correlation could be observed between the responsiveness of blast progenitors to GM-CSF, and the numbers or affinities of GM-CSF binding sites demonstrated on blast cells. In studies with neoplastic lymphoid cells from four patients, 125I-GM-CSF also specifically bound in two cases, while response to GM-CSF was not observed in these cases. These results indicate that the expression of GM-CSF receptor is not restricted to the GM-CSF-responsive AML blast cells, but can be observed in other AML blast cells and even in neoplastic lymphoid cells.
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PMID:Binding properties and proliferative effects of human recombinant granulocyte-macrophage colony-stimulating factor in primary leukemia and lymphoma. 255 16

In vitro culture of either human peripheral blood monocytes or murine peritoneal macrophages for 72 hr in the presence of macrophage colony-stimulating factor (M-CSF) dramatically increased their subsequent ability to mediate antibody-dependent cellular cytotoxicity (ADCC). The M-CSF-treated cells were more effective in ADCC at lower effector to target cell ratios and in the presence of lower concentrations of tumor-specific monoclonal antibody than the untreated control cells. Two other hematopoietic cytokines, granulocyte-macrophage colony-stimulating factor and interleukin-3, reported to enhance other macrophage effector functions were ineffective in promoting the development of ADCC by cultured human monocytes. All three hematopoietic growth factors were capable of enhancing the ability of the cultured monocytes to secrete TNF alpha; however, TNF alpha is unlikely to be an important cytotoxic factor in ADCC because neutralizing antibodies against TNF alpha had no affect on ADCC in vitro. Further, much higher concentrations of M-CSF were required to augment monocyte TNF alpha release (20-100 ng/ml) than ADCC capacity (1-10 ng/ml). These results suggest that M-CSF administration might prove effective in increasing the tumoricidal activities of tumor-specific monoclonal antibodies by enhancing the capacity of monocytes and macrophages to mediate ADCC.
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PMID:Macrophage colony-stimulating factor enhances monocyte and macrophage antibody-dependent cell-mediated cytotoxicity. 264 26

3F8 is a murine monoclonal IgG3 antibody specific for the tumor-associated antigen ganglioside GD2. Previous in vitro studies suggest that tumor regressions observed in a phase I clinical trial of 3F8 may be attributable to complement activation by 3F8 and to 3F8-dependent cellular cytotoxicity (ADCC) with lymphocytes. We now describe 3F8-mediated ADCC of GD2-positive tumor targets (melanoma and neuroblastoma) with human granulocytes and report that recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) enhanced this phenomenon. Cytotoxicity required binding of 3F8 to the low-affinity Fc receptor type III (CD16) on the granulocytes and was poor with tumor-binding monoclonal antibodies of other immunoglobulin (ie, non-IgG3) subclasses. GM-CSF (2 to 20 ng/mL) increased ADCC by 93% to 267% at limiting dilutions of 3F8 (1 microgram/mL). With most GD2-positive cell lines tested, this effect translated into a tenfold or greater augmentation in 3F8 efficiency at mediating ADCC. Comparable enhancement occurred whether GM-CSF was present in the ADCC assay or granulocytes were incubated with GM-CSF and washed before the assay. Nonoxidative mechanisms may be important for ADCC since 3F8 mediated ADCC with granulocytes from two children with chronic granulomatous disease; this cytotoxicity was also enhanced by GM-CSF. Since GM-CSF induces a neutrophilia in patients, our data suggest that this cytokine may have the potential of amplifying 3F8 antitumor activity in patients by increasing effector cell numbers and by priming granulocytes for greater cytotoxicity.
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PMID:GM-CSF enhances 3F8 monoclonal antibody-dependent cellular cytotoxicity against human melanoma and neuroblastoma. 265 66

We have recently reported that cultured human monocytes are susceptible to lysis by autologous lymphokine-activated killer (LAK) cells. In an attempt to modulate the sensitivity of monocytes to LAK-mediated lysis, monocytes were cultured in the presence of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF). GM-CSF was found to enhance the susceptibility of monocytes to lysis by LAK cells by 2- to 5-fold over that of untreated cells in a dose-dependent manner. As little as 10 units of GM-CSF per milliliter was sufficient to induce increased sensitivity. In a kinetics study, susceptibility of monocytes increased after 2 days of incubation with GM-CSF, with peak sensitivity occurring from 4 to 6 days of culture. The effect of GM-CSF appeared to be specific for monocytes within the circulating peripheral blood cells because nonadherent cells (NAC) and granulocytes, which are normally resistant to LAK-mediated lysis, did not become susceptible after treatment with GM-CSF. In cold-target inhibition experiments, unlabeled GM-CSF-treated monocytes, but not untreated monocytes, could block the lysis of FMEX, a human melanoma tumor cell line, as well as freshly isolated tumor cells. Finally, LAK cells specifically bound to GM-CSF-treated monocytes in significantly higher percentages than to control monocytes. In summary, our results indicate that GM-CSF was capable of enhancing the susceptibility of monocytes to LAK lysis possibly via increased binding or expression of target structure(s).
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PMID:Induction of human monocyte susceptibility to lymphokine-activated killer cell lysis by granulocyte-macrophage colony-stimulating factor. 267 Feb

Proliferation in vitro of the in vivo passaged murine B cell tumor line BCL1 has been used as a standard assay for mouse interleukin-5 (IL-5) for a number of years. We demonstrate that this line will also respond to human IL-5. The response to murine IL-5 is abrogated by transforming growth factor-beta and to a lesser extent by interferon-gamma. This suggests a possible regulatory role for these lymphokines in the proliferation of B cells induced by IL-5. Other purified recombinant lymphokines were also tested for their ability to induce BCL1 proliferation. The lymphokines IL-1, IL-2, IL-3, and IL-6 had no effect on the growth of BCL1. In contrast, IL-4 and more surprisingly granulocyte-macrophage colony-stimulating factor (GM-CSF) also induced proliferation of this cell. These effects could be inhibited by specific antibodies directed against the respective lymphokines. These data suggest that GM-CSF, as well as IL-4 and IL-5, may be yet another regulator of neoplastic and possibly even normal B-cell growth and differentiation.
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PMID:The BCL1 B lymphoma responds to IL-4, IL-5, and GM-CSF. 267 47

The present investigation demonstrates that leukoregulin, a cytokine secreted by natural killer (NK) lymphocytes up-regulates the sensitivity of tumor cells to lymphokine-activated killer (LAK) cell cytotoxicity. It has been previously established that leukoregulin increases the sensitivity of sarcoma, carcinoma and leukemia cells to natural killer (NK) cell cytotoxicity. Tumor cells were treated with leukoregulin for 1 h at 37 degrees C and tested for sensitivity to NK and LAK cytotoxicity in a 4-h chromium-release assay. NK-resistant Daudi, QGU and C4-1 human cervical carcinoma cells became sensitive to NK cytotoxicity after leukoregulin treatment, and their sensitivity to LAK was increased two- to sixfold. Y-79 retinoblastoma cells, which are moderately sensitive to NK and very sensitive to LAK, became increasingly sensitive (two- to four-fold) to both NK and LAK cell cytotoxicity. Recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF), recombinant interleukin-1 (alpha and beta), recombinant interferon gamma, recombinant tumor necrosis factor or combinations of the latter two failed to up-regulate tumor cell sensitivity to NK and LAK cell cytotoxicity. However, treatment with recombinant interferon gamma for 16-18 h, GM-CSF and interleukin-1 beta for 1 h induced a state of target cell resistance to both NK and LAK cell cytotoxicity. Leukoregulin may have an important physiological function in modulating NK and LAK cell cytotoxicity by increasing the sensitivity of target cells to these natural cellular immunocytotoxicity mechanisms.
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PMID:Leukoregulin up-regulation of tumor cell sensitivity to natural killer and lymphokine-activated killer cell cytotoxicity. 268 71

Three lines of transgenic mice carrying the human T-cell lymphotropic virus type 1 tax gene have previously been reported to develop neurofibromas composed of perineural fibroblasts (S. H. Hinrichs, M. Nerenberg, R. K. Reynolds, G. Khoury, and G. Jay, Science 237:1340-1343, 1987; M. Nerenberg, S. H. Hinrichs, R. K. Reynolds, G. Khoury, and G. Jay, Science 237:1324-1329, 1987). Tumors from these mice and tumor cell lines derived from them expressed high levels of tax RNA and protein. They also expressed high levels of the granulocyte-macrophage colony-stimulating factor (GM-CSF) gene as measured by proliferative responses of FD-CP1 target cells using conditioned media from tumor cells and by Northern (RNA) blot analysis of RNA from tumors and tumor cell lines. Although other tissues, such as salivary glands and muscles, in the transgenic mice also expressed high levels of tax, they did not express the gene for GM-CSF. This indicates that tissue-specific cellular factors, in addition to tax, are required for GM-CSF gene expression. Systemic effects of excessive GM-CSF production were demonstrated by infiltration of polymorphonuclear leukocytes into tumor tissues which are not necrotic, by peripheral granulocytosis, and by splenomegaly resulting from myeloid hyperplasia. The interleukin-2 (IL-2) receptor was also found to be expressed by the tumors and tumor cell lines as measured by IL-2-binding and cross-linking studies. This is the first demonstration that the IL-2 receptor can be activated by tax in a nonlymphoid cell type. These in vivo findings are consistent with other reports which have demonstrated in vitro cis-regulatory elements within the 5'-flanking regions of the genes for GM-CSF and the IL-2 receptor which are responsive to trans activation by the tax gene.
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PMID:trans activation of granulocyte-macrophage colony-stimulating factor and the interleukin-2 receptor in transgenic mice carrying the human T-lymphotropic virus type 1 tax gene. 268 63

The mouse T-cell lymphoma cell line EL4.E1 constitutively synthesizes mouse mammary tumor virus (MMTV) transcripts encoding either the entire proviral genome or segments of it. In addition to these conventional mRNAs, however, an mRNA of about 1 kilobase accumulates after induction of these cells with phorbol myristate acetate (PMA). The accumulation of this transcript is strongly inhibited by the immunosuppressive agent cyclosporin A. Its pattern of induction by PMA and suppression by cyclosporin A is thus the same as seen for several lymphokine mRNAs in these cells, including interleukin-2 and granulocyte-macrophage colony-stimulating factor. The short MMTV transcript is the most abundant PMA-induced transcript in EL4.E1 cells, but was not found in a series of other leukocyte tumor cell lines. It is initiated from a novel promoter within the env gene, and a segment of 1,161 nucleotides is then spliced out. The major part of the transcript is a copy of the long terminal repeat (LTR) of MMTV. The MMTV proviral genomes in these cells, and the short transcript, contain a 491-nucleotide deletion in the LTR compared with the normal MMTV provirus. The resulting open reading frame could encode a protein of molecular weight 22,800, which is a likely candidate for an LTR-related protein with a similar molecular weight recently described in this system (J. Racevskis, J. Virol. 58:441-449, 1986).
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PMID:Phorbol diester-inducible, cyclosporine-suppressible transcription from a novel promoter within the mouse mammary tumor virus env gene. 283 99


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