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001-es BibID:	BIBFORM024154
Első szerző:	Szabó Gábor (biofizikus)
Cím:	Cross-linking of CD4 in a TCR/CD3-juxtaposed inhibitory state : a pFRET study / Szabo G., Weaver J. L., Pine P. S., Rao P. E., Aszalos A.
Dátum:	1995
Megjegyzések:	Instances when T cell activation via the T cell receptor/CD3 complex is suppressed by anti-CD4 Abs are generally attributed either to the topological separation of CD4-p56(kk) from CD3, or their improper apposition. Photobleaching fluorescence resonance energy transfer measurements permitted direct analysis of these alternatives on human peripheral blood lymphocytes. Distinction between changes of relative antigen densities or positioning was made possible by simultaneously recording donor and acceptor fluorescence in the energy transfer experiment performed on homogeneous populations of flow-sorted cells. We show here that CD4 stays in the molecular vicinity of CD3, while anti-CD3 stimulation is suppressed by anti-CD4 or cross-linked HIV gp120. Our data suggest that cross-linking of CD4 through particular epitopes is capable of inhibiting activation driven by Abs binding to specific sites on CD3 without major topological sequestration of the Ags, in such a way that additional positive signals will also be affected. Thus, these and other related cases of negative signaling via CD4 may be interpreted in terms of functional uncoupling rather than a wide physical separation of CD4 from the T cell receptor-CD3 complex
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban analysis blood Cells Energy Transfer Epitopes Fluorescence Fluorescence Resonance Energy Transfer Hiv Human lymphocyte Lymphocytes Photobleaching
Megjelenés:	Biophysical Journal. - 68 : 3 (1995), p. 1170-1176. -
További szerzők:	Weaver, James L. Pine, P. Scott Rao, P. Aszalos Adorján
Internet cím:	elektronikus változat Intézményi repozitóriumban (DEA) tárolt változat DOI
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001-es BibID:	BIBFORM024105
035-os BibID:	(scopus)0026577623 (wos)A1992HH57800008
Első szerző:	Szabó Gábor (biofizikus)
Cím:	Epitope mapping by photobleaching fluorescence resonance energy transfer measurements using a laser scanning microscope system / Szabo G., Pine P. S., Weaver J. L., Kasari M., Aszalos A.
Dátum:	1992
Megjegyzések:	The donor photobleaching method (T. M. Jovin and D. J. Arndt-Jovin. 1989. Annu. Rev. Biophys. Biophys. Chem. 18:271-308.) has been adapted to an ACAS 570 (laser scanning microscope) system to measure fluorescence resonance energy transfer (FRET) on individual human peripheral blood T cells. Photobleaching was completed in approximately 100 ms in our case and it followed double-exponential kinetics. The energy transfer efficiency (E) was approximately 20% between the CD4 epitopes OKT4-FITC and Leu-3a-PE as well as between OKT4E-FITC and OKT4-PE. E was approximately 8% between OKT4-FITC and Leu-4-PE (alpha-CD3) and barely detectable (approximately 4%) from OKT4-FITC to Leu-5b-PE (alpha-CD2). The E values obtained by the photobleaching method were highly reproducible both in repeated measurement of identical samples and in experiments with different batches of cells and were in agreement with the flow cytometric donor quenching measurements. As expected, E measured between primary and secondary layers of antibodies increased (from approximately 14% to approximately 28%) when F(ab')2 fragments were substituted for whole antibody molecules as the donor. On a T cell line we mapped the distance between the idiotypic determinant of the T cell receptor (TcR) and the Leu-4 epitope of CD3 as proximal as E = 28%, as compared to E = 4% between a framework TcR epitope and Leu-4. In the latter case, however, approximately 40% less Leu-4 was bound suggesting that the antigen binding site of TcR is in close proximity with one of the two CD3 epsilon-chains, which hence are not equivalent
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Antibodies binding site blood Cell Line Cells Energy Transfer Epitopes Fluorescence Fluorescence Resonance Energy Transfer FRET Human Kinetics Photobleaching
Megjelenés:	Biophysical Journal. - 61 : 3 (1992), p. 661-670. -
További szerzők:	Pine, P. Scott Weaver, James L. Kasari, Mark Aszalos Adorján
Internet cím:	elektronikus változat Intézményi repozitóriumban (DEA) tárolt változat DOI
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