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No Abstract Available.
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No Abstract Available.
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Subject(s)
Cell Line , Cell Proliferation , Cytokines , Leukemia, Erythroblastic, AcuteABSTRACT
The pleckstrin homology (PH) domain is a protein module of approximately 100 amino acids, that has been found in signaling molecules, including serinelthreonine kinase, GTPase-activating protein, phospholipase, and some cytoskeletal proteins. Although the specific function of PH domain has not been defined yet, it is believed that this domain is involved in the regulation of signal transduction pathway. The expression plasmids of human PLCg PH domains were constructed to see the roles of them in IL-6 signal transduction. When these expression plasmids are transfected into B9 cells, only N-terminal of PH domain inhibited IL-6-induced B9 cell proliferation. These results suggest that N-terminal of PH domain is critical for IL-6 signal transduction in B9 cells. To search the binding proteins associated PH domains of PLCy1 in B9 cells, Glutathione S-trnaferase (GST) fusion proteins containg PH domains were expressed in E. coli. Then, IL-6-dependent B9 cells were treated with 10 unit/ml IL-6 and the cell lysates were immunoprecipited with GST-PH doman fusion proteins. In vitro kinase assay of immune complex demonstrated that p38 (38 KDa) protein was coprecipitated with NC fusion protein, but IL-6 had no additional effect on it. When S-methaionine labelled cell lysates were used for immunoprecipitation, the same result was observed, conforming the association of p38 with NC motive of PH domain.
Subject(s)
Humans , Amino Acids , Antigen-Antibody Complex , Carrier Proteins , Cell Proliferation , Cytoskeletal Proteins , Glutathione , GTPase-Activating Proteins , Hydrogen-Ion Concentration , Immunoprecipitation , Interleukin-6 , Phospholipases , Phosphotransferases , Plasmids , Signal TransductionABSTRACT
BACKGROUND: The human keratinocyte can synthesize interleukin 6 (IL-6) under certain conditions, and the IL-6 synthesis is inhibited by interleukin 4 (IL-4) in the human monocyte. OBJECTIVE: To find out what kind of stimulating agents can induce the IL-6 production and whether IL-4 affects the production of IL-6 in the human cultured keratinocytes. METHODS: We stimulated the keratinocytes with either lipopolysaccharide (LPS), fetal bovine serum (FBS), human recombinant interferon-gamma(IFN-gamma) to induce the IL-6 production, and treated the keratinocytes, which stimulated either with 10% FBS or human recombinant IFN-gamma, with human recombinant IL-4. RESULTS: The LPS stimulation resulted in no increase of IL-6 levels in the keratinocyte supernatants. When the keratinocytes were stimulated either with 1%, 5%, 10% FBS with or without 5 microgram/ml LPS, significantly increased amounts of IL-6 were detected. The level of IL-6 in the keratinocytes treated with the human recombinant IFN-gamma increased, too. The human recombinant IL-4 downregulates the secretion of IL-6 by the keratinocytes which were activated either with 10% FBS or human recombinant IFN-gamma. CONCLUSION: We have shown that it is possible to induce the IL-6 synthesis by stimulating the keratinocytes and that human recombinant IL-4 profoundly inhibits the synthesis of IL-6. So we suggest that there may be a cytokine network which regulates the primary immune response in the skin.
Subject(s)
Humans , Interleukin-4 , Interleukin-6 , Interleukins , Keratinocytes , Monocytes , SkinABSTRACT
No abstract available.
Subject(s)
Intercellular Adhesion Molecule-1 , Interleukin-6 , KeratinocytesABSTRACT
Childhood minimal change nephrotic syndrome (MCNS) has often been associated with allergic symptoms such as urticaria, bronchial asthma, atopic dermatitis, allergic rhinitis and elevated IgE levels and referred to involve immune dysfunction. Fc epsilon RII is known to be involved in IgE production and response. Interleukin-4 is being recognized as a major cytokine up-regulating IgE production. Hence the present study is aimed at investigating the role of interleukin-4 and Fc epsilon RII in the pathogenesis of MCNS. IgE was measured by ELISA. Fc epsilon RII was analyzed by fluorescence activated cell scanner (FAC-scan) by double antibody staining with anti Leu16-FITC and anti Leu20-PE. Soluble IgE receptor was measured by ELISA using anti CD23 antibody (3-5-14). Interleukin-4 activities were measured by CD23 expression on purified human tonsillar B cells. Serum IgE levels were significantly higher in MCNS (1,507 +/- 680 IU/dl) than in normal controls (123 +/- 99.2 IU/dl). A significantly higher expression of membrane Fc epsilon RII was noted for MCNS (41 +/- 12%) than that in normal controls (18 +/- 6.2%) (p < 0.001). Soluble CD23 levels were also significantly higher in MCNS (198 +/- 39.3%) than in normal controls (153 +/- 13.4) (p < 0.01). Interleukin-4 activity in sera of MCNS (12U/ml) was also significantly higher than normal controls (4.5U/ml). These results indicate that increased production of Fc epsilon RII and interleukin-4 may play an important role in the pathogenesis of MCNS.