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001-es BibID:	BIBFORM046086
Első szerző:	Dóczy-Bodnár Andrea (biofizikus)
Cím:	Class I HLA oligomerization at the surface of B cells is controlled by exogenous [béta]2-microglobulin : implications in activation of cytotoxic T lymphocytes / Bodnar A., Bacso Z., Jenei A., Jovin T. M., Edidin M., Damjanovich S., Matko J.
Dátum:	2003
ISSN:	1460-2377
Megjegyzések:	Submicroscopic molecular clusters (oligomers) of class I HLA have been detected by physical techniques [e.g. fluorescence resonance energy transfer (FRET) and single particle tracking of molecular diffusion] at the surface of various activated and transformed human cells, including B lymphocytes. Here, the sensitivity of this homotypic association to exogenous beta(2)-microglobulin (beta(2)m) and the role of free heavy chains (FHC) in class I HLA oligomerization were investigated on a B lymphoblastoid cell line, JY. Scanning near-field optical microscopy and FRET data both demonstrated that FHC and class I HLA heterodimers are co-clustered at the cell surface. Culturing the cells with excess beta(2)m resulted in a reduced co-clustering and decreased molecular homotypic association, as assessed by FRET. The decreased HLA clustering on JY target cells (antigen-presenting cells) was accompanied with their reduced susceptibility to specific lysis by allospecific CD8(+) cytotoxic T lymphocytes (CTL). JY B cells with reduced HLA clustering also provoked significantly weaker T cell activation signals, such as lower expression of CD69 activation marker and lower magnitude of TCR down-regulation, than did the untreated B cells. These results together suggest that the actual level of beta(2)m available at the cell surface can control CTL activation and the subsequent cytotoxic effector function through regulation of the homotypic HLA-I association. This might be especially important in some inflammatory and autoimmune diseases where elevated serum beta(2)m levels are reported.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	International Immunology. - 15 : 3 (2003), p. 331-339. -
További szerzők:	Bacsó Zsolt (1963-) (biofizikus) Jenei Attila (1966-) (biofizikus) Jovin, Thomas M. Edidin, Michael Damjanovich Sándor (1936-2017) (biofizikus) Matkó János (1952-) (biológus)
Pályázati támogatás:	T034393 OTKA T030411 OTKA F034487 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM046278
Első szerző:	Matkó János (biológus)
Cím:	Luminescence quenching by long range electron transfer : a probe of protein clustering and conformation at the cell surface / Matko Janos, Jenei Attila, Wei Taiyin, Edidin Michael
Dátum:	1995
ISSN:	0196-4763
Megjegyzések:	Quenching of luminescence from fluorescent and phosphorescent probes by nitroxide spin labels with a long range electron transfer (LRET) mechanism (44,45) has been tested as a tool to monitor association/clustering and conformational changes of cell surface proteins. The membrane proteins were labeled with monoclonal antibodies or Fab fragments conjugated with luminescent probes or water-soluble nitroxide spin labels. The method was tested as a probe of 3 different aspects of protein-protein association involving class I MHC molecules: (1) interaction between the heavy and light chains of the MHC molecules, (2) clustering, self-association of MHC molecules, (3) proximity of MHC molecules to transferrin receptors of fibroblasts or surface immunoglobulin molecules of B lymphoblasts. The extent of quenching upon increasing the fractional density of the quencher was sensitive for protein association in accordance with earlier immunoprecipitation and flow cytometric Forster-type energy transfer (FCET) data obtained on the same cells. These data suggest that the LRET quenching can be used as intra- or intermolecular ruler in a 0.5-2.5 nm distance range. This approach is simpler (measurements only on donor side) and faster than many other experimental techniques in screening physical association or conformational changes of membrane proteins by means of spectrofluorimetry, flow cytometry, or microscope based imaging.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Cytometry. - 19 : 3 (1995), p. 191-200. -
További szerzők:	Jenei Attila (1966-) (biofizikus) Wei, Taiyin Edidin, Michael
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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