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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 role of CD11/CD18 leukocyte adhesion molecules and their ligands in mediating non-major histocompatibility complex (MHC) restricted lymphocyte cytotoxicity is controversial. In order to examine the role of target cell intercellular adhesion molecule-1 (ICAM-1; CD54), a ligand of lymphocyte function-associated antigen (LFA-1) (CD11a/CD18), we exposed the human leukemia cell line, HL-60, to a variety of agents implicated in modulating ICAM-1 expression and/or sensitivity to lymphocyte cytolysis. Exposure of HL-60 cells to retinoic acid (RA), interferon (IFN)-alpha, IFN-beta, and IFN-gamma induced protection from lymphokine-activated killer (LAK) cytolysis. Only RA and IFN-gamma induced ICAM-1 expression. Tumor necrosis factor and vitamin D3, which also induced ICAM-1 expression, increased HL-60 sensitivity to LAK lysis. Granulocyte-macrophage colony-stimulating factor also increased sensitivity to LAK lysis; ICAM-1 was not induced. The state of cellular differentiation and expression of class I and II MHC antigens also did not correlate with sensitivity to LAK cytolysis. Exposure of untreated HL-60 cells and HL-60 cells expressing ICAM-1 to monoclonal antibody (mAb) versus ICAM-1 did not modulate LAK sensitivity. Exposure of LAK cells to mAb versus LFA-1 partially inhibited cytolysis; mAb versus CD18 inhibited cytolysis more completely. HL-60 cells were resistant to natural killer lysis; exposure to the various experimental agents did not alter sensitivity. We conclude that leukemic cell sensitivity to LAK cytolysis can be modulated by a variety of agents. Although our results suggest a role for leukocyte CD11/CD18 adhesion molecules in LAK cytolysis, the poor correlation between ICAM-1 expression and sensitivity to LAK lysis suggest that interactions other than LFA-1/ICAM-1 conjugation may be more central to the processes involved.
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PMID:Modulation of leukemic cell sensitivity to lymphokine-activated killer cytolysis: role of intercellular adhesion molecule-1. 136 53

Tumor necrosis factor (TNF)-alpha and TNF-beta have multiple effects on human acute myeloid leukemia (AML) cells in vitro, including (1) synergistic stimulation of proliferation with interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) and upregulation of interleukin-3 (IL-3) and GM-CSF receptors; (2) inhibition of granulocyte-CSF (G-CSF)-induced growth and rapid downmodulation of G-CSF receptors; and (3) induction of autocrine growth. Recently, two distinct TNF receptors (TNF-Rs), TNF-R(p55) and TNF-R(p75), have been identified. In this study, we show that both receptor types may be expressed by AML blasts. It has been investigated whether the different effects of TNF on AML blasts can be explained by differential activation of the distinct TNF-R structures. For this purpose, we used the monoclonal antibodies HTR-1 and HTR-9, specifically recognizing TNF-R(p55), and UTR-1, specific for TNF-R(p75). TNF-(alpha and -beta) mediated synergistic activation with IL-3/GM-CSF, upregulation of IL-3/GM-CSF receptors, inhibition of G-CSF-induced growth, and rapid downmodulation of G-CSF receptors exclusively result from activation of TNF-R(p55). In certain cases in which TNF-alpha, rather than TNF-beta, induces AML growth through an autocrine mechanism, both TNF-R(p55) and (p75) are involved. These data indicate that the variety of TNF responses observed in AML can only be partially explained by differential activation of the TNF-R(p55) and (p75) structures, and that TNF-R(p55) on AML blasts can transduce both positive (synergism with IL-3/GM-CSF) and negative regulatory signals (inhibition of G-CSF-induced proliferation) following TNF activation.
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PMID:Involvement of tumor necrosis factor (TNF) receptors p55 and p75 in TNF responses of acute myeloid leukemia blasts in vitro. 138 4

We describe dendritic cell progenitors within the CD34+ stem cell compartment in neonatal cord blood and identify growth factors contributing to their differentiation. Granulocyte-macrophage colony-stimulating factor (GM-CSF), although mainly promoting the growth and differentiation of monocyte-macrophages (mono-m psi s), also induced the differentiation of cells with the distinctive morphological features of dendritic cells (DCs). Tumor necrosis factor (TNF) in combination with GM-CSF promoted further growth of both cell types but most notably increased the DC content. In situ analysis revealed that the cells exhibiting DC morphology were positive for class II major histocompatibility complex antigens but were CD14 negative, did not exhibit nonspecific esterase activity, and were nonphagocytic. Moreover, the mixed leukocyte reaction stimulatory capacity of cultures with the higher DC content was greater. TNF, interleukin-1 (IL-1), IL-6, or platelet-derived growth factor (PDGF) was inactive in promoting stem cell proliferation or DC morphology. IL-1 or PDGF synergized with GM-CSF to increase mono-m psi-associated cell proliferation but did not increase the DC content. The development of a common DC-monocyte precursor was suggested by the presence of colony-forming unit-like clusters containing mono-m psi s and DCs and one sharp proliferative peak. The loss of DC morphology after 21 days, coupled with increases in mono-m psi-associated markers and a constant number of viable cells, further suggests that DC morphology may fluctuate in culture or is a transient feature acquired by certain cells of the mono-m psi lineage.
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PMID:TNF in combination with GM-CSF enhances the differentiation of neonatal cord blood stem cells into dendritic cells and macrophages. 138 91

Tumor necrosis factor (TNF) as well as the hematopoietic growth factors interleukin-3, interleukin-5, and granulocyte-macrophage colony-stimulating factor affect several eosinophil functions. We previously reported (J. Exp. Med. 1989. 170: 467; 1990. 172: 1577) that the hematopoietic growth factors also potentiate leukotriene C4 (LTC4) formation by eosinophils as well as basophils stimulated with soluble chemotactic peptides such as N-formyl-methionyl-leucyl-phenylalanine (FMLP), but whether TNF also modulates lipid mediator generation in normodense eosinophils triggered with FMLP is unknown. Here we show that a short preincubation (10 min) of human eosinophils purified from healthy donors with low concentrations of TNF (5-150 pM) strongly enhances LTC4 formation in response to FMLP. However, basophil mediator release is not affected by TNF preincubation. Nerve growth factor (NGF), the receptor of which is structurally related to the TNF receptors, tended to suppress lipid mediator synthesis in eosinophils, in contrast to its profound potentiating capacity on basophil mediator release. Thus, the present study demonstrates a first difference in susceptibility of eosinophils and basophils towards cytokines, indicating that TNF and NGF may regulate the relative importance of effector functions of these otherwise closely related cell types.
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PMID:Opposing effects of tumor necrosis factor-alpha and nerve growth factor upon leukotriene C4 production by human eosinophils triggered with N-formyl-methionyl-leucyl-phenylalanine. 155 9

We have examined the regulation of complement dependent phagocytosis by macrophage-activating cytokines. Tumor necrosis factor (TNF)-alpha and granulocyte-macrophage colony-stimulating factor (GM-CSF), but not interferon-gamma, interleukin-4 or macrophage-CSF, stimulated ingestion of the encapsulated fungal pathogen Cryptococcus neoformans by resident peritoneal macrophages in vitro. This was dependent upon opsonization of the yeasts with complement, 72 h of incubation with the cytokines for maximum effect, and the obligate involvement of the macrophage CR3 receptor. TNF-alpha and GM-CSF synergized at low concentrations, resulting in dramatic up-regulation of phagocytosis when compared to either cytokine alone. Supernatants from C. neoformans-specific T cells also increased macrophage phagocytic efficiency. Finally, the administration of neutralizing mAb specific for TNF-alpha and GM-CSF increased mortality in C. neoformans-infected mice, and induced the rapid progression of disease with involvement of the brain and meninges. We conclude that TNF-alpha and GM-CSF are potent regulators of complement-dependent phagocytosis by murine macrophages. Macrophage activation with these two cytokines can completely overcome the anti-phagocytic properties of the virulent yeasts. Our results, therefore, implicate TNF-alpha and GM-CSF as important mediators of resistance to encapsulated pathogens such as C. neoformans where ingestion of the organism is a critical process in host resistance.
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PMID:Cytokine enhancement of complement-dependent phagocytosis by macrophages: synergy of tumor necrosis factor-alpha and granulocyte-macrophage colony-stimulating factor for phagocytosis of Cryptococcus neoformans. 160 Oct 35

Tumor necrosis factor (TNF) acts as a potent enhancer of granulocyte-macrophage colony-stimulating factor (GM-CSF)- and interleukin-3 (IL-3)-induced human acute myeloid leukemia (AML) growth in vitro. We have analyzed the effects of TNF alpha on the expression of GM-CSF and IL-3 receptors on AML cells. Incubation of blasts from seven patients with AML in serum-free medium with TNF (10(3) U/mL) and subsequent binding studies using 125I-GM-CSF and 125I-IL-3 show that TNF increases the specific binding of GM-CSF (30% to 280%) and IL-3 (40% to 600%) in all cases. From Scatchard plot analysis it appears that TNF upregulates (1) low-affinity GM-CSF binding sites, (2) common high-affinity IL-3/GM-CSF binding sites, and (3) unique (non-GM-CSF binding) IL-3 binding sites. The effect of TNF is dose dependent and is half maximal at a concentration of 100 U/mL, and becomes evident at 18 hours of incubation with TNF at 37 degrees C, but not at 0 degree C. The GM-CSF dose-response curve of AML-colony-forming units plateaus at a higher level in the presence of TNF, which indicates that additional numbers of cells become responsive to GM-CSF. Incubation of AML blasts with the phorbol ester 12-0-tetradecanoylphorbol-13-acetate or formyl-Met-Leu-Phe (protein kinase C activators) does not influence GM-CSF receptor expression, suggesting that receptor upregulation by TNF is not mediated through activation of protein kinase C. On the other hand, the protein synthesis inhibitor cycloheximide abrogates receptor upregulation induced by TNF. In contrast to these findings in AML, TNF does not upregulate GM-CSF receptor numbers on blood granulocytes or monocytes. We conclude that TNF exerts positive effects on growth factor receptor expression of hematopoietic cells.
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PMID:Tumor necrosis factor regulates the expression of granulocyte-macrophage colony-stimulating factor and interleukin-3 receptors on human acute myeloid leukemia cells. 182 89

A 4-year-old female with severe combined immunodeficiency (SCID) had normal numbers of T cells in circulation and normal T cell subsets. However, her T cells proliferated poorly to mitogens and did not proliferate to antigens or to anti-CD3 mAb. Interleukin-2 (IL-2) receptor expression was normal but IL-2 synthesis was undetectable. The addition of recombinant IL-2 to a mitogen-stimulated culture resulted in normalization of the proliferative response. Northern blot analysis of total RNA derived from the patient's T cells revealed a weak or absent expression of mRNA coding for IL-2, IL-3, IL-4, and IL-5. In contrast, there were normal amounts of mRNA coding for granulocyte-macrophage colony-stimulating factor (GM-CSF). Tumor necrosis factor and IL-6 production was also normal. Nuclear run on transcriptional assays revealed markedly decreased levels of newly initiated nuclear transcripts coding for IL-2, IL-3, IL-4, and IL-5 and normal levels of GM-CSF transcripts in patient relative to control lymphocytes. These results indicate that the patient's T cells suffered from a defect affecting the transcription of multiple T cell lymphokines and suggest that abnormalities affecting the production of T cell lymphokines may underlie some of the primary immunodeficiency diseases.
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PMID:Novel immune deficiencies: defective transcription of lymphokine genes. 193 9

Retention of inflammatory mediators and cells in the middle ear cleft during chronic otitis media with effusion (COME), results in ongoing inflammation with the potential for pathologic changes and hearing loss. Cytokines are glycoproteins produced by macrophages and other cells. Activities of cytokines include fever production, osteoclast, fibroblast, phagocyte and cytotoxic cell activation, regulation of antibody formation, and inhibition of cartilage, bone and endothelial cell growth. Using enzyme-linked immunospecific assays we measured levels of six cytokines in middle ear effusions (MEE) from children with COME. Significant levels of four cytokines: interleukin-1-beta (greater than 50 pg/ml), interleukin-2 (greater than 300 pg/ml), tumor necrosis factor-alpha (greater than 40 pg/ml), and gamma-interferon (greater than 6.25 pg/ml) were found in 51%, 54%, 63%, and 19% of MEE, respectively. In contrast, levels of a fifth cytokine, granulocyte-macrophage colony-stimulating factor, and a sixth cytokine, interleukin-4, were undetectable. Age was observed to have a significant effect on the levels of specific cytokines. Interleukin-1 (IL-1) correlated inversely (P less than .02) with age such that the younger the child, the higher the level of IL-1 in MEE. Tumor necrosis factor-alpha (TNF) correlated directly (P less than .005) with age such that the older the child, the higher the level of TNF in MEE. Children undergoing tympanostomy on multiple occasions had average MEE TNF levels (234.2 +/- 109.1 pg/mg total protein) that were nearly 14 times higher (P less than .005) than those from children undergoing their first tympanostomy (16.9 +/- 3.0 pg/mg total protein). Thus IL-1 correlated with the early stages of COME, while TNF correlated with persistence of disease. The presence of these cytokines in MEE may be responsible for the mucosal damage, bone erosion, fibrosis, and resulting hearing loss seen in some cases of COME.
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PMID:Characterization of cytokines present in middle ear effusions. 199 67

Tumor necrosis factor (TNF alpha and TNF beta) and interleukin-1 (IL-1) are mediators of immunity and inflammation that induce different, but partially overlapping responses in human endothelial cells (HEC). We compared the effect of purified recombinant human TNF alpha, TNF beta and IL-1 on the production of platelet-activating factor (PAF) in HEC. After 30-60 min of treatment with TNF alpha or TNF beta, HEC produce and partially release considerable amounts of PAF, which reach a maximum after 4-6 h. In HEC treated with IL-1 PAF production is detectable after 2 h and peaks at 8-12 h. More than twice as much PAF is produced in response to optimal concentrations of TNF alpha than in response to TNF beta or IL-1. However, PAF synthesis is stimulated by lower molar concentrations of IL-1 than TNF alpha and TNF beta. The ability to induce PAF synthesis in HEC seems to be restricted to these three cytokines, as shown by negative results obtained with other cytokines that activate HEC (interferons, granulocyte- and granulocyte-macrophage colony-stimulating factor, epithelial growth factor, fibroblast growth factor, transforming growth factor beta), or participate in the inflammatory process (IL-6, platelet-derived growth factor).
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PMID:Selected cytokines promote the synthesis of platelet-activating factor in vascular endothelial cells: comparison between tumor necrosis factor alpha and beta and interleukin-1. 213 80

Culture medium conditioned by activated human T lymphocytes enhances the in vitro cytotoxicity of purified human eosinophils toward Schistosoma mansoni larvae, suggesting the existence of a mechanism for T lymphocyte regulation of eosinophil function. Here we show that purified biosynthetic (recombinant) human T lymphocyte granulocyte-macrophage colony-stimulating factor (GM-CSF) enhanced markedly two eosinophil functions: cytotoxicity toward schistosomula by a mean of 676%, and calcium ionophore A23187-induced generation of leukotriene C4 (LTC4) by a mean of 135%. Augmentation of each eosinophil function by GM-CSF was time- and dose-dependent, with a dose-response relationship at concentrations between 1 and 20 pM. Tumor necrosis factor (TNF) enhanced eosinophil cytotoxicity with slower kinetics, a different dose-dependence relationship, and to a lower maximum, as compared with GM-CSF. There was no detectable effect of TNF on calcium ionophore A23187-induced generation of LTC4. The effect of GM-CSF on arachidonic acid metabolism to LTC4 reached a plateau with 60 min of incubation before stimulation with ionophore, and was characterized by an initial augmentation of the intracellular level of LTC4 and a subsequent increment in extracellular LTC4. Thus, GM-CSF can serve as a mediator for T lymphocyte regulation of functions of mature eosinophils. It is also the first defined macromolecule known to enhance metabolism of membrane-derived arachidonic acid via the 5-lipoxygenase pathway.
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PMID:Enhancement of human eosinophil cytotoxicity and leukotriene synthesis by biosynthetic (recombinant) granulocyte-macrophage colony-stimulating factor. 309 27


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