965 resultados para Ifn-alpha-beta
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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Thesis (doctoral)--Friedrich-Wilhelms-Universitat zu Berlin, 1894.
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Thesis (doctoral)--Universitat Basel, 1895.
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Thesis (doctoral)--Universite de Geneve, 1896.
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Despite more than a 10-fold increase in T cell numbers in G-CSF-mobilized peripheral blood stem cell (PBSC) grafts, incidence and severity of acute graft-vs-host disease (GVHD) are comparable to bone marrow transplantation. As CD1d-restricted, Valpha24(+)Vbeta11(+) NKT cells have pivotal immune regulatory functions and may influence GVHD, we aimed to determine whether G-CSF has any effects on human NKT cells. In this study, we examined the frequency and absolute numbers of peripheral blood NKT cells in healthy stem cell donors (n = 8) before and following G-CSF (filgrastim) treatment. Effects of in vivo and in vitro G-CSF on NKT cell cytokine expression profiles and on responsiveness of NKT cell subpopulations to specific stimulation by alpha-galactosylceramide (alpha-GalCer) were assessed. Contrary to the effects on conventional T cells, the absolute number of peripheral blood NKT cells was unaffected by G-CSF administration. Furthermore, responsiveness of NKT cells to alpha-GalCer stimulation was significantly decreased (p < 0.05) following exposure to G-CSF in vivo. This hyporesponsiveness was predominantly due to a direct effect on NKT cells, with a lesser contribution from G-CSF-mediated changes in APC. G-CSF administration resulted in polarization of NKT cells toward a Th2, IL-4-secreting phenotype following alpha-GalCer stimulation and preferential expansion of the CD4(+) NKT cell subset. We conclude that G-CSF has previously unrecognized differential effects in vivo on NKT cells and conventional MHC-restricted T cells, and effects on NKT cells may contribute to the lower than expected incidence of GVHD following allogeneic peripheral blood stem cell transplantation.
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Immunotherapy strategies aimed at increasing human Valpha24(+)Vbeta11(+) natural killer T (NKT) cell numbers are currently a major focus. To provide further information towards the goal of NKT cell-based immunotherapy, we assessed the effects of age, cancer status and prior anticancer treatment on NKT cell numbers and their expansion capacity following alpha-galactosylceramide (alpha-GalCer) stimulation. The percentage and absolute number of peripheral blood NKT cells was assessed in 40 healthy donors and 109 solid cancer patients ( colorectal ( n = 33), breast ( n = 10), melanoma ( n = 17), lung ( n = 8), renal cell carcinoma ( n = 10), other cancers ( n = 31)). Responsiveness to alpha-GalCer stimulation was also assessed in 28 of the cancer patients and 37 of the healthy donors. Natural killer T cell numbers were significantly reduced in melanoma and breast cancer patients. While NKT numbers decreased with age in healthy donors, NKT cells were decreased in these cancer subgroups despite age and sex adjustments. Prior radiation treatment was shown to contribute to the observed reduction in melanoma patients. Although cancer patient NKT cells were significantly less responsive to alpha-GalCer stimulation, they remained capable of substantial expansion. Natural killer T cells are therefore modulated by age, malignancy and prior anticancer treatment; however, cancer patient NKT cells remain capable of responding to alpha-GalCer-based immenotherapies.
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The structures of acetylcholine-binding protein ( AChBP) and nicotinic acetylcholine receptor ( nAChR) homology models have been used to interpret data from mutagenesis experiments at the nAChR. However, little is known about AChBP-derived structures as predictive tools. Molecular surface analysis of nAChR models has revealed a conserved cleft as the likely binding site for the 4/7 alpha-conotoxins. Here, we used an alpha 3 beta 2 model to identify beta 2 subunit residues in this cleft and investigated their influence on the binding of alpha-conotoxins MII, PnIA, and GID to the alpha 3 beta 2 nAChR by two-electrode voltage clamp analysis. Although a beta 2-L119Q mutation strongly reduced the affinity of all three alpha-conotoxins, beta 2-F117A, beta 2-V109A, and beta 2-V109G mutations selectively enhanced the binding of MII and GID. An increased activity of alpha-conotoxins GID and MII was also observed when the beta 2-F117A mutant was combined with the alpha 4 instead of the alpha 3 subunit. Investigation of A10L-PnIA indicated that high affinity binding to beta 2-F117A, beta 2-V109A, and beta 2-V109G mutants was conferred by amino acids with a long side chain in position 10 (PnIA numbering). Docking simulations of 4/7 alpha-conotoxin binding to the alpha 3 beta 2 model supported a direct interaction between mutated nAChR residues and alpha-conotoxin residues 6, 7, and 10. Taken together, these data provide evidence that the beta subunit contributes to alpha-conotoxin binding and selectivity and demonstrate that a small cleft leading to the agonist binding site is targeted by alpha-conotoxins to block the nAChR.
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To investigate the role of peroxisome proliferator-activated receptors (PPARs) chi and beta in the differentiation of colon cancer cells, we differentiated HT-29 cells using sodium butyrate (NaB) and culturing post-confluence and assessed differentiation using the marker intestinal alkaline phosphatase. While PPAR chi levels only changed with culturing post confluence, PPAR beta levels increased independent of the method of differentiation. To explore further the differences induced by NaB. we assessed changes in both PPAR isoforms in MCF-7 breast cancer cells cultured in the presence of NaB over 48 h. Again a very different expression pattern was observed with PPAR-1 increasing after 4 h and remaining elevated, while PPAR beta increased transiently. Our studies suggest that the expression of PPARs is dependent upon both the method of differentiation and on time. Moreover, these studies show that changes in levels are not required for the differentiation of colon cancer cell lines, whereas changes in PPAR beta are more closely associated with differentiation. (c) 2005 Elsevier Inc. All rights reserved.
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We have previously shown that human papillomavirus virus-like particles (VLPs) are able to activate the Ras/MAP kinase pathway. Ras can also elicit an anti-apoptotic signal via PI3-kinase so we investigated this further. Here we show that binding of VLPs from HPV types 6b, 18, 3 1, 35 and BPV1 results in activation of PI3-kinase. Activation was achieved by either L1 or L1/L2 VLPs and was dependent on both VLP-cell interaction and correct conformation of the virus particle. VLP-induced PI3-kinase activity resulted in efficient downstream signaling to Akt and consequent phosphorylation of FKHR and GSK3 beta. We also present evidence that PV signaling is activated via the alpha 6 beta 4 integrin. These data suggest that papillomaviruses use a common receptor that is able to signal through to Ras. Combined activation of the Ras/MAP kinase and PI3-kinase pathways may be beneficial for the virus by increasing cell numbers and producing an environment more conducive to infection. (c) 2006 Elsevier Inc. All rights reserved
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beta-Hydroxy-beta-methylbutyrate (HMB; 50 microM) has been shown to attenuate the depression in protein synthesis in murine myotubes in response to lipopolysaccharide (LPS), tumor necrosis factor-alpha (TNF-alpha) with or without interferon-gamma (IFN-gamma), and angiotensin II (ANG II). The mechanism for the depression of protein synthesis by all three agents was the same and was attributed to activation of double-stranded RNA-dependent protein kinase (PKR) with the subsequent phosphorylation of eukaryotic initiation factor 2 (eIF2) on the alpha-subunit as well as increased phosphorylation of the elongation factor (eEF2). Myotubes expressing a catalytically inactive PKR variant, PKRDelta6, showed no depression of protein synthesis in response to either LPS or TNF-alpha, confirming the importance of PKR in this process. There was no effect of any of the agents on phosphorylation of mammalian target of rapamycin (mTOR) or initiation factor 4E-binding protein (4E-BP1), and thus no change in the amount of eIF4E bound to 4E-BP1 or the concentration of the active eIF4E.eIF4G complex. HMB attenuated phosphorylation of eEF2, possibly by increasing phosphorylation of mTOR, and also attenuated phosphorylation of eIF2alpha by preventing activation of PKR. These results suggest that HMB may be effective in attenuating muscle atrophy in a range of catabolic conditions.