scholarly journals Expression of mRNA and immunoreactivity for the granulocyte/macrophage colony-stimulating factor in activated human eosinophils.

1991 ◽  
Vol 174 (3) ◽  
pp. 749-752 ◽  
Author(s):  
R Moqbel ◽  
Q Hamid ◽  
S Ying ◽  
J Barkans ◽  
A Hartnell ◽  
...  

Using in situ hybridization, we have shown that activated human peripheral blood eosinophils express mRNA for granulocyte/macrophage colony-stimulating factor (GM-CSF). Between 15 and 27% of eosinophils gave positive hybridization signals for GM-CSF mRNA after stimulation with the calcium ionophore A23187 or interferon gamma, and 4 and 6% after incubation with interleukin 3 (IL-3) or IL-5. Activated eosinophils also gave specific immunoreactivity with an anti-GM-CSF polyclonal antibody, suggesting translation of the mRNA. These data indicate that eosinophils may be an important source of GM-CSF at sites of allergic inflammation. Furthermore, the identification of GM-CSF production by human eosinophils suggests that the pro-inflammatory potential of this cell type may be substantially greater than hitherto recognized.

1994 ◽  
Vol 5 (1) ◽  
pp. 119-128 ◽  
Author(s):  
A Tsuboi ◽  
E S Masuda ◽  
Y Naito ◽  
H Tokumitsu ◽  
K Arai ◽  
...  

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-2 (IL-2) are produced by stimulation with phorbol-12-myristate acetate (PMA) and calcium ionophore (A23187) in human T cell leukemia Jurkat cells. The expression of GM-CSF and IL-2 is inhibited by immunosuppressive drugs such as cyclosporin A (CsA) and FK506. Earlier studies on the IL-2 gene expression showed that overexpression of calcineurin (CN), a Ca2+/calmodulin-dependent protein phosphatase, can stimulate transcription from the IL-2 promoter through the NF-AT-binding site. In this study, we obtained evidence that transfection of the cDNAs for CN A (catalytic) and CN B (regulatory) subunits also augments transcription from the GM-CSF promoter and recovers the transcription inhibited by CsA. The constitutively active type of the CN A subunit, which lacks the auto-inhibitory and calmodulin-binding domains, acts in synergy with PMA to activate transcription from the GM-CSF promoter. We also found that the active CN partially replaces calcium ionophore in synergy with PMA to induce expression of endogenous GM-CSF and IL-2. By multimerizing the regulatory elements of the GM-CSF promoter, we found that one of the target sites for the CN action is the conserved lymphokine element 0 (CLE0), located at positions between -54 and -40. Mobility shift assays showed that the CLE0 sequence has an AP1-binding site and is associated with an NF-AT-like factor, termed NF-CLE0 gamma. NF-CLE0 gamma binding is induced by PMA/A23187 and is inhibited by treatment with CsA. These results suggest that CN is involved in the coordinated induction of the GM-CSF and IL-2 genes and that the CLE0 sequence of the GM-CSF gene is a functional analogue of the NF-AT-binding site in the IL-2 promoter, which mediates signals downstream of T cell activation.


1991 ◽  
Vol 174 (3) ◽  
pp. 745-748 ◽  
Author(s):  
H Kita ◽  
T Ohnishi ◽  
Y Okubo ◽  
D Weiler ◽  
J S Abrams ◽  
...  

Human peripheral blood eosinophils released eosinophil survival-enhancing activity when stimulated with the calcium ionophore, ionomycin. The release of activity was detected as early as 3 h after stimulation and was inhibited by an immunomodulating agent, cyclosporin A. The survival-enhancing activity was completely abolished by treatment with anti-interleukin 3 (IL-3) and anti-granulocyte/macrophage colony-stimulating factor (GM-CSF) monoclonal antibodies. Moreover, IL-3 and GM-CSF were measurable in ionomycin-stimulated eosinophil supernatants by immunoassay. Eosinophils produced approximately one-half as much IL-3 and one-fifth as much GM-CSF as ionomycin-stimulated mononuclear cells. Neutrophils also produced IL-3 and GM-CSF, but the amounts were less than those produced by eosinophils. These observations suggest a novel role for eosinophils in pathophysiology of allergic inflammation and host defense mechanisms.


Blood ◽  
1996 ◽  
Vol 88 (4) ◽  
pp. 1206-1214 ◽  
Author(s):  
RL Rosen ◽  
KD Winestock ◽  
G Chen ◽  
X Liu ◽  
L Hennighausen ◽  
...  

Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces immediate effects in monocytes by activation of the Janus kinase (JAK2) and STAT transcription factor (STAT5) pathway. Recent studies have identified homologues of STAT5, STAT5A, and STAT5B, as well as lower molecular weight variants of STAT5. To define the activation of the STAT5 homologues and lower molecular weight variant in human monocytes and monocytes differentiated into macrophages by culture in macrophage- CSF (M-CSF), we measured the GM-CSF induced tyrosine phosphorylation of STAT5A, STAT5B, and any lower molecular weight STAT5 isoforms. Freshly isolated monocytes expressed 94-kD STAT5A, 92-kD STAT5B, and an 80-kD STAT5A molecule. Whereas 94-kD STAT5A was clearly tyrosine phosphorylated and bound to the enhancer element, the gamma response region (GRR), of the Fc gamma RI gene, substantially less tyrosine phosphorylated STAT5B bound to the immobilized GRR element. Macrophages lost their ability to express the 80-kD STAT5A protein, but retained their ability to activate STAT5A. STAT5A-STAT5A homodimers and STAT5A- STAT5B heterodimers formed in response to GM-CSF. Therefore, activation of STAT5A predominates compared to STAT5B when assayed by direct immunoprecipitation and by evaluation of bound STATs to immobilized GRR. Selective activation of STAT5 homologues in addition to generation of lower molecular isoforms may provide specificity and control to genes expressed in response to cytokines such as GM-CSF.


Blood ◽  
1991 ◽  
Vol 77 (10) ◽  
pp. 2259-2265 ◽  
Author(s):  
DK Blanchard ◽  
MB Michelini-Norris ◽  
JY Djeu

In the present study, culture supernatants from larger granular lymphocytes (LGL) that were activated with Candida albicans antigens were shown to stimulate the ability of neutrophils to inhibit fungal growth. Identification of the activation factors showed that granulocyte-macrophage colony-stimulating factor (GM-CSF), a hematopoietic growth factor, was involved. Human peripheral blood mononuclear cells were fractionated by Percoll density centrifugation and each subpopulation of cells was stimulated with C albicans yeast cells. GM-CSF was produced in those fractions enriched for LGL, but not T lymphocytes or adherent monocytes. Additionally, the phenotype of the GM-CSF-producing cell was found to be CD2+, CD16+, HLA-DR+, and negative for CD4, CD8, and CD15. Kinetic studies demonstrated that GM- CSF appeared in the supernatants within 2 days of culture and continued to be produced up to 7 days. Optimal stimulation of LGL was seen at a ratio of 3 heat-killed C albicans yeast cells per LGL. Thus, LGL play an important role in host defense against this opportunistic pathogen by producing cytokines, including GM-CSF, which in turn activates the fungicidal activity of neutrophils.


Blood ◽  
1995 ◽  
Vol 85 (9) ◽  
pp. 2579-2586 ◽  
Author(s):  
F Levi-Schaffer ◽  
P Lacy ◽  
NJ Severs ◽  
TM Newman ◽  
J North ◽  
...  

We have previously shown that normal-density human peripheral blood eosinophils transcribe and translate mRNA for granulocyte-macrophage colony-stimulating factor (GM-CSF) and that the intracellular distribution was granular as assessed by light microscopy immunocytochemistry. The present study was conducted to confirm this apparent association between GM-CSF and the crystalloid granule using a subcellular fractionation method for human eosinophils and immunogold electron microscopy (EM). Highly purified (> 99%, by negative selection using anti-CD16 immunomagnetic microbeads) human peripheral blood eosinophils were obtained from four asthmatic subjects (not taking systemic medication), homogenized and density fractionated (5 x 10(7) cells/subject) on linear Nycodenz gradients. Twenty-four fractions were collected from each cell preparation and analyzed for marker enzyme activities as well as total protein. Dot blot analysis with specific monoclonal antibodies (MoAbs) was used to detect the eosinophil granule proteins major basic protein (MBP) and eosinophil cationic protein (ECP). An anti-CD9 MoAb was used as an eosinophil plasma membrane marker. Lactate dehydrogenase (LDH) was used as a cytosolic marker. Immunoreactivity for GM-CSF was detected by a specific enzyme-linked immunosorbent assay using a polyclonal antihuman GM-CSF antibody and confirmed by dot blot. GM-CSF coeluted with the cellular fractions containing granule markers (MBP, ECP, eosinophil peroxidase, hexosaminidase, and arylsulphatase), but not those containing cytoplasm (LDH+) or membrane (CD9+) markers. EM examination of pooled fractions associated with the peak of GM-CSF immunoreactivity confirmed that they contained crystalloid and small granules, but not plasma membrane. In addition, quantification, using immunogold labeling with an anti/GM-CSF MoAb, indicated preferential localization of gold particles over the eosinophil granule cores of intact cells. Thus, our results indicate that GM-CSF resides as a granule-associated, stored mediator in unstimulated human eosinophils.


Blood ◽  
1991 ◽  
Vol 77 (10) ◽  
pp. 2259-2265 ◽  
Author(s):  
DK Blanchard ◽  
MB Michelini-Norris ◽  
JY Djeu

Abstract In the present study, culture supernatants from larger granular lymphocytes (LGL) that were activated with Candida albicans antigens were shown to stimulate the ability of neutrophils to inhibit fungal growth. Identification of the activation factors showed that granulocyte-macrophage colony-stimulating factor (GM-CSF), a hematopoietic growth factor, was involved. Human peripheral blood mononuclear cells were fractionated by Percoll density centrifugation and each subpopulation of cells was stimulated with C albicans yeast cells. GM-CSF was produced in those fractions enriched for LGL, but not T lymphocytes or adherent monocytes. Additionally, the phenotype of the GM-CSF-producing cell was found to be CD2+, CD16+, HLA-DR+, and negative for CD4, CD8, and CD15. Kinetic studies demonstrated that GM- CSF appeared in the supernatants within 2 days of culture and continued to be produced up to 7 days. Optimal stimulation of LGL was seen at a ratio of 3 heat-killed C albicans yeast cells per LGL. Thus, LGL play an important role in host defense against this opportunistic pathogen by producing cytokines, including GM-CSF, which in turn activates the fungicidal activity of neutrophils.


Blood ◽  
1991 ◽  
Vol 78 (7) ◽  
pp. 1842-1852 ◽  
Author(s):  
SR McColl ◽  
JF DiPersio ◽  
AC Caon ◽  
P Ho ◽  
PH Naccache

Abstract The aim of the present study is to evaluate the involvement of human neutrophil tyrosine kinase(s) in the signal transduction mechanism of granulocyte-macrophage colony-stimulating factor (GM-CSF). Stimulation of neutrophils with GM-CSF resulted in a time- and dose-dependent phosphorylation of several proteins having estimated molecular weights of approximately 40, 55, 74, 97, 118, and 155 Kd, detected by immunoblot using a monoclonal antibody directed against phosphotyrosine. GM-CSF-induced tyrosine phosphorylation was inhibited in a dose- and time-dependent manner by the tyrosine kinase inhibitor erbstatin. Using this inhibitor, we were able to correlate tyrosine phosphorylation with several functional effects of GM-CSF on human neutrophils. Pretreatment of neutrophils with erbstatin before incubation with GM-CSF completely inhibited the GM-CSF-induced intracellular alkalinization, downregulation of the leukotriene B4 receptor, enhancement of fMet-Leu-Phe-induced intracellular calcium mobilization, as well as the accumulation of mRNA for the proto- oncogene c-fos. Taken together, these data suggest that tyrosine kinase activation in human neutrophils plays a critical regulatory role in both the stimulation and priming of neutrophil function by GM-CSF.


Blood ◽  
1991 ◽  
Vol 78 (7) ◽  
pp. 1842-1852
Author(s):  
SR McColl ◽  
JF DiPersio ◽  
AC Caon ◽  
P Ho ◽  
PH Naccache

The aim of the present study is to evaluate the involvement of human neutrophil tyrosine kinase(s) in the signal transduction mechanism of granulocyte-macrophage colony-stimulating factor (GM-CSF). Stimulation of neutrophils with GM-CSF resulted in a time- and dose-dependent phosphorylation of several proteins having estimated molecular weights of approximately 40, 55, 74, 97, 118, and 155 Kd, detected by immunoblot using a monoclonal antibody directed against phosphotyrosine. GM-CSF-induced tyrosine phosphorylation was inhibited in a dose- and time-dependent manner by the tyrosine kinase inhibitor erbstatin. Using this inhibitor, we were able to correlate tyrosine phosphorylation with several functional effects of GM-CSF on human neutrophils. Pretreatment of neutrophils with erbstatin before incubation with GM-CSF completely inhibited the GM-CSF-induced intracellular alkalinization, downregulation of the leukotriene B4 receptor, enhancement of fMet-Leu-Phe-induced intracellular calcium mobilization, as well as the accumulation of mRNA for the proto- oncogene c-fos. Taken together, these data suggest that tyrosine kinase activation in human neutrophils plays a critical regulatory role in both the stimulation and priming of neutrophil function by GM-CSF.


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