摘要:

AbstractA multipotent hemopoietic cell line has been employed to assess the influence of the hemopoietic growth factors, IL-3, GM-CSF, G-CSF, and CSF-1 on the processes of self-renewal, the generation of lineage restricted progenitor cells and the production of mature neutrophils and macrophages. At a high concentration of IL-3, the cells undergo self-renewal and demonstrate little or no ability to undergo differentiation in the presence of the other growth factors. In the absence of IL-3, the cells show minimal (GM-CSF) or no (G-CSF or CSF-1) ability to respond to these other growth factors. When combined with a low concentration of IL-3, the ability of the cells to respond to GM-CSF, G-CSF, and CSF-1 is enhanced and a selective preference for the neutrophil or macrophage lineage is seen depending on the combination used, i.e., the presence of CSF-1 preferentially promotes macrophage development and G-CSF preferentially promotes neutrophil development. Conditions optimal for neutrophil development were seen using a combination of low IL-3 concentrations plus GM-CSF plus G-CSF. In such conditions, the cells undergo extensive proliferation and progressively lose their clonogenic potential (i.e., differentiation self-renewal) and acquire the biochemical markers characteristic of fully mature phagocytes.

ISSN:0897-7194    

DOI:10.3109/08977199009071506

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

AbstractThe role of tyrosine phosphorylation in the signal transduction of four hematopoietic colony-stimulating factors (IL-3, IL-4, G-CSF, and GM-CSF) in myeloid cells was investigated. In DA-3 cells, both IL-3 and GM-CSF stimulated, within 10 min, the tyrosine phosphorylation of similar proteins with molecular masses of 70, 56, 51, 42, and 38 kD, as well as two different 140-kD proteins, one being the IL-3 receptor. Both of these growth factors were able to increase the transcription, within 1 hr, of two IL-3-inducible genes–c-myc and the gamma chain of the T-cell receptor. In NFS-60 cells, tyrosine phosphorylation on a common 56-kD protein occurred within 10 min in response to either G-CSF or IL-3. In addition, IL-3 stimulation increased the phosphorylation of the 140-kD IL-3 receptor. Both growth factors were able to increase transcription of the c-myc gene within 1 hr. Finally, in NFS-107 cells, IL-3 and IL-4 stimulated the tyrosine phosphorylation, within 10 min, of two different 140-kD proteins, one of which was the IL-3 receptor. Both growth factors were able, within 1 hr, to increase the transcription of the c-myc and gamma chain of the T-cell receptor genes.

ISSN:0897-7194    

DOI:10.3109/08977199009071507

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

AbstractInterleukin-3 (IL-3) regulates the proliferation of myeloid, erythroid, and lymphoid cells. Previous reports showed IL-3 binding restricted to a single high-affinity(Kd= 50-200 pin) site. Here, we demonstrate by equilibrium studies an additional binding site for IL-3 with lower apparent affinity(Kd=5-20 iym).Furthermore, kinetic analysis shows that two binding sites for IL-3 exist: IL-3 dissociates slowly from the first site (I½=4hr; k−1=2.7x10−3min−1), whereas it dissociates rapidly (T½=4.0 min; k−1= 0.116 min−1) from the second site. Cross-linking showed that [125I]IL-3 binding to the 115- and 140-kD proteins was not saturable at concentrations commensurate with high-affinity binding and IL-3 dissociated rapidly from these same molecules. Thus, the low affinity IL-3 receptor is a molecule(s) of 115- to 140-kD.

ISSN:0897-7194    

DOI:10.3109/08977199009071508

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

AbstractLeukemia inhibitory factor (LIF) is a glycoprotein with divergent activities: It induces the differentiation of certain myeloid leukemic cells, inhibits the differentiation of embryonic stem cells, and promotes bone remodellingin vivoandin vitro.The murine LIF gene has been assigned to the proximal region of chromosome 11 at sub-bands A1-A2, by analysis of a panel of mouse x Chinese hamster somatic cell hybrids and byin situhybridization. Interestingly, the proximal portion of chromosome 11 has been shown, by virtue of its parental origin effects, to contain gene(s) involved in fetal growth. It is also interesting that there is a preponderance of chromosome 11 abnormalities in embryonal carcinoma cells. The localization of the murine LIF gene confirms the homology of a portion of murine chromosome 11 with human chromosome 22q, the site of the human LIF gene.

ISSN:0897-7194    

DOI:10.3109/08977199009071509

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

AbstractTransforming growth factor-α-like immunoreactivity (TGF-α-ir) was visualized in the adult rat forebrain using three antisera directed against carboxyterminal sequences in the TGF-αprecursor. Using immunoperoxidase and immunofluorescence techniques with all three antisera, TGF-λ-ir was found to be present in a subpopulation of astrocytes in the forebrain. Striatal and pallidal regions of the basal ganglia were studied in detail. In the striatum, there was an uneven distribution of astrocytes containing TGF-α-ir, with the greatest number in the dorsal medial third of the caudate-putamen and the overlying corpus callosum/external capsule. In addition, the region of the caudate-putamen bordering the globus pallidus contained numerous clusters of TGF-α-ir astrocytes. The globus pallidus itself contained numerous and more evenly distributed TGF-α-ir astrocytes. Other pallidal structures-including the ventral pallidum, entopeduncular nucleus, and substantia nigra pars reticulata–contained moderate numbers of TGF-α-ir astrocytes. These results suggest that TGF-αprecursor is present and, perhaps, synthesized in astrocytes. A related growth factor, epidermal growth factor (EGF), has also been reported to be present in pallidal regions of rat brain. Therefore, the TGF-α/EGF family of trophic factors may play an important role in the function of the central nervous system.

ISSN:0897-7194    

DOI:10.3109/08977199009071510

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor