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001-es BibID:	BIBFORM059572
Első szerző:	Bene László (biofizikus)
Cím:	Nanoparticle energy transfer on the cell surface / László Bene, Gergely Szentesi, László Mátyus, Rezső Gáspár, Sándor Damjanovich
Dátum:	2005
ISSN:	0952-3499
Megjegyzések:	Membrane topology of receptors plays an important role in shaping transmembrane signalling of cells. Among the methods used for characterizing receptor clusters, fluorescence resonance energy transfer between a donor and acceptor fluorophore plays a unique role based on its capability of detecting molecular level (2-10 nm) proximities of receptors in physiological conditions. Recent development of biotechnology has made possible the usage of colloidal gold particles in a large size range for specific labelling of cells for the purposes of electron microscopy. However, by combining metal and fluorophore labelling of cells, the versatility of metal-fluorophore interactions opens the way for new applications by detecting the presence of the metal particles by the methods of fluorescence spectroscopy. An outstanding feature of the metal nanoparticle-fluorophore interaction is that the metal particle can enhance spontaneous emission of the fluorophore in a distance-dependent fashion, in an interaction range essentially determined by the size of the nanoparticle. In our work enhanced fluorescence of rhodamine and cyanine dyes was observed in the vicinity of immunogold nanoparticles on the surface of JY cells in a flow cytometer. The dyes and the immunogold were targetted to the cell surface receptors MHCI, MHCII, transferrin receptor and CD45 by monoclonal antibodies. The fluorescence enhancement was sensitive to the wavelength of the exciting light, the size and amount of surface bound gold beads, as well as the fluorophore-nanoparticle distance. The intensity of 90 degrees scattering of the incident light beam was enhanced by the immunogold in a concentration and size-dependent fashion. The 90 degrees light scattering varied with the wavelength of the incident light in a manner characteristic to gold nanoparticles of the applied sizes. A reduction in photobleaching time constant of the cyanine dye was observed in the vicinity of gold particles in a digital imaging microscope. Modulations of 90 degrees light scattering intensity and photobleaching time constant indicate the role of the local field in the fluorescence enhancement. A mathematical simulation based on the electrodynamic theory of fluorescence enhancement showed a consistency between the measured enhancement values, the inter-epitope distances and the quantum yields. The feasibility of realizing proximity sensors operating at distance ranges larger than that of the conventional Forster transfer is demonstrated on the surface of living cells
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban Antibodies Antibodies,Monoclonal Antigens,CD45 B-Lymphocytes Biophysics Carbocyanines Cell Membrane Cells Cultured chemistry diagnostic use Dyes Energy Transfer Fluorescence Fluorescent Dyes Gold Humans Hungary immunology Light metabolism methods Microscopy Nanotechnology Photobleaching Receptors,Transferrin Research Rhodamines Spectrometry,Fluorescence Support
Megjelenés:	Journal Of Molecular Recognition. - 18 : 3 (2005), p. 236-253. -
További szerzők:	Szentesi Gergely (1976-) (kémia-fizika tanár) Mátyus László (1956-) (biofizikus) Gáspár Rezső (1944-) (biofizikus) Damjanovich Sándor (1936-2017) (biofizikus)
Pályázati támogatás:	OTKA-T042618 OTKA OTKA-TS040773 OTKA OTKA-T043509 OTKA OTKA-T043087 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM004858
Első szerző:	Bene László (biofizikus)
Cím:	Detection of receptor trimers on the cell surface by flow cytometric fluorescence energy homotransfer measurements / László Bene, János Szöllősi, Gergely Szentesi, László Damjanovich, Rezső Gaspar, Thomas A. Waldmann, Sándor Damjanovich
Dátum:	2005
ISSN:	0006-3002
Megjegyzések:	Fluorescence energy homotransfer offers a powerful tool for the investigation of the state of oligomerization of cell surface receptors on a cell-by-cell basis by measuring the polarized components of fluorescence intensity of cells labeled with fluorescently stained antibodies. Here we describe homotransfer-based methods for the flow cytometric detection and analysis of hetero- and homo-associations of cell surface receptors. Homotransfer efficiencies for two- and three-body energy transfer interactions are defined and their frequency distribution curves are computed from the fluorescence anisotropy distributions of multiple-labeled cells. The fractions of receptors involved in homo-clustering is calculated based on the dependence of the fluorescence anisotropy on the surface concentration of the fluorescently stained antibodies. A homotransfer analysis of the homo- and hetero-clustering of the MHCI and MHCII glycoproteins, the cytokine receptor IL-2Ralpha, transferrin receptor and the receptor-type tyrosine phosphatase CD45 on JY B and Kit-225-K6 T cells is presented. We investigated how various factors such as the type of dye, rotational mobility of the dye and dye-targeting antibody, as well as the wavelength of the exciting light affect the homotransfer. We show that the homotransfer technique combined with the high statistical resolution of flow cytometry is an effective tool for detecting different oligomeric states of receptors by using fluorophores having restricted rotational mobility on the time scale of fluorescence
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban Fluorescence anisotropy Receptor clustering MHCI and MHCII glycoprotein IL-2Rα Transferrin receptor CD45
Megjelenés:	Biochimica et Biophysica Acta (BBA). Molecular Cell Research. - 1744 : 2 (2005), p. 176-198. -
További szerzők:	Szöllősi János (1953-) (biofizikus) Szentesi Gergely (1976-) (kémia-fizika tanár) Damjanovich László (1960-) (általános sebész) Gáspár Rezső (1944-) (biofizikus) Waldmann, Thomas A. Damjanovich Sándor (1936-2017) (biofizikus)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
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001-es BibID:	BIBFORM039514
Első szerző:	Matkó János (biológus)
Cím:	GPI-microdomains (membrane rafts) and signaling of the multi-chain interleukin-2 receptor in human lymphoma/leukemia T cell lines / Matko, J., Bodnar, A., Vereb, G., Bene, L., Vamosi, G., Szentesi, G., Szollosi, J., Gaspar, R., Horejsi, V., Waldmann, T. A., Damjanovich, S.
Dátum:	2002
ISSN:	0014-2956
Megjegyzések:	Subunits (alpha, beta and gamma) of the interleukin-2 receptor complex (IL-2R) are involved in both proliferative and activation-induced cell death (AICD) signaling of T cells. In addition, the signaling beta and gamma chains are shared by other cytokines (e.g. IL-7, IL-9, IL-15). However, the molecular mechanisms responsible for recruiting/sorting the alpha chains to the signaling chains at the cell surface are not clear. Here we show, in four cell lines of human adult T cell lymphoma/leukemia origin, that the three IL-2R subunits are compartmented together with HLA glycoproteins and CD48 molecules in the plasma membrane, by means of fluorescence resonance energy transfer (FRET), confocal microscopy and immuno-biochemical techniques. In addition to the beta and gamma(c) chains constitutively expressed in detergent-resistant membrane fractions (DRMs) of T cells, IL-2Ralpha (CD25) was also found in DRMs, independently of its ligand-occupation. Association of CD25 with rafts was also confirmed by its colocalization with GM-1 ganglioside. Depletion of membrane cholesterol using methyl-beta-cyclodextrin substantially reduced co-clustering of CD25 with CD48 and HLA-DR, as well as the IL-2 stimulated tyrosine-phosphorylation of STATs (signal transducer and activator of transcription). These data indicate a GPI-microdomain (raft)-assisted recruitment of CD25 to the vicinity of the signaling beta and gamma(c) chains. Rafts may promote rapid formation of a high affinity IL-2R complex, even at low levels of IL-2 stimulus, and may also form a platform for the regulation of IL-2 induced signals by GPI-proteins (e.g. CD48). Based on these data, the integrity of these GPI-microdomains seems critical in signal transduction through the IL-2R complex.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	European Journal Of Biochemistry. - 269 : 4 (2002), p. 1199-1208. -
További szerzők:	Dóczy-Bodnár Andrea (1970-) (biofizikus) Vereb György (1965-) (biofizikus, orvos) Bene László (1963-) (biofizikus) Vámosi György (1967-) (biofizikus) Szentesi Gergely (1976-) (kémia-fizika tanár) Szöllősi János (1953-) (biofizikus) Gáspár Rezső (1944-) (biofizikus) Horejsi, Václav Waldmann, Thomas A. Damjanovich Sándor (1936-2017) (biofizikus)
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