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1.

001-es BibID:BIBFORM054305
035-os BibID:PMID: 18243342
Első szerző:Hancz Anikó
Cím:Integration of signals mediated by B-cell receptor, B-cell activating factor of the tumor necrosis factor family (BAFF) and Fas (CD95) / Anikó Hancz, Zoltán Hérincs, Zsuzsa Neer, Gabriella Sármay, Gábor Koncz
Dátum:2008
ISSN:0165-2478
Megjegyzések:The survival of the mature resting B cells depends on signaling from B cell receptor (BCR), and a plethora of positive and negative regulators, that maintain cellular homeostasis and ultimately determine cell's fate, i.e., survival or programmed death (apoptosis). Among these regulators we have investigated the B cell activating factor belonging to tumor necrosis factor family (BAFF) and the prototypic death receptor Fas/CD95 mediated signals. We have shown that BAFF inhibits Fas-mediated cell death, however, the BCR-driven survival signals were not strengthened by BAFF. Therefore, we propose that BAFF may function independently of the antigen specificity of BCR, thus may enhance the risk of autoimmune diseases by promoting the survival of bystander B cells in the germinal center.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
B-cell
BAFF
Fas
apoptosis
selection
signaling
Megjelenés:Immunology Letters. - 116 : 2 (2008), p. 211-217. -
További szerzők:Hérincs Zoltán Neer Zsuzsa Sármay Gabriella Koncz Gábor (1970-) (biológus, immunológus)
Pályázati támogatás:D48469
OTKA
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2.

001-es BibID:BIBFORM041843
Első szerző:Hancz Anikó
Cím:TLR9-mediated signals rescue B-cells from Fas-induced apoptosis via inactivation of caspases / Anikó Hancz, Gábor Koncz, Dániel Szili, Gabriella Sármay
Dátum:2012
ISSN:0165-2478
Megjegyzések:The death receptor, CD95/Fas, serves to eliminate potentially dangerous, self-reactive B cells. Engagement of B-cell receptors (BCR) on mature B-cells mediates the escape from cell death resulting in the activation and expansion of antigen specific clones. In addition to the antigen receptors, the receptors of B-cell activating factor belong to the tumor necrosis factor (TNF) family (BAFFR); moreover, the pattern recognition receptor, TLR9 may also deliver survival signals inhibiting Fas-mediated death of B-cells. Our aim was to compare the mechanism of BCR-induced and the BAFFR- or TLR9-stimulated rescue of B-cells from CD95/Fas-mediated apoptosis. We have found that BAFFR and TLR9 collaborate with BCR to protect B-cells from Fas-induced elimination and the rescue is independent of protein synthesis. The results revealed that the TLR9- and BCR-triggered rescue signals are transmitted through partially overlapping pathways; the protein kinase C (PKC) and the abl kinase induced phosphorylation may inactivate caspases in both CpG and anti-IgG stimulated cells. However, PI3-K activation is crucial upon the BCR driven anti-apoptotic effect, while p38 MAPK-mediated inactivation of caspases seems to play essential role in TLR9-mediated protection against Fas-induced programmed cell death.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Apoptosis
BAFF
B-cells
Fas
TLR9
Megjelenés:Immunology Letters. - 143 : 1 (2012), p. 77-84. -
További szerzők:Koncz Gábor (1970-) (biológus, immunológus) Szili Dániel Sármay Gabriella
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3.

001-es BibID:BIBFORM054323
035-os BibID:PMID: 9533441
Első szerző:Koncz Gábor (biológus, immunológus)
Cím:FcγRIIb inhibits both B cell receptor- and CD19-induced Ca2+ mobilization in FcγR-transfected human B cells / Gábor Koncz, János Gergely, Gabriella Sármay
Dátum:1998
ISSN:0953-8178
Megjegyzések:Fc gamma RIIb (CD32) controls antibody production by down-regulating cell activation, when co-clustered with B cell antigen receptors (BOB) in vivo, via immune complexes consisting of secreted IgG and antigen, Fc gamma RIIb-BCR co-ligation in vitro was shown to inhibit the Ca2+ influx from the extracellular space, the mechanism of which is not fully understood, Human B cells express Fc gamma RIIb1 and Fc gamma RIIb2, differing only in a 19 amino acid long insert in the cytoplasmic tail of the former, To elucidate whether Fc gamma RIIb1 and Fc gamma RIIb2 isoforms show any difference in the down-regulation of B cells, we have studied the effect of co-clustering of BCR and Fc gamma RIIb1 or Fc gamma RIIb2 on the Ca2+ signaling in a Burkitt's lymphoma cell line, ST486, transfected with the two isoforms respectively, We have shown here, for the first time, that co-aggregation of BCR and Fc gamma RIIb may also inhibit Ca2+ release from the endoplasmic reticulum pool of human B cells, Both isoforms mediated this inhibition and the inhibitory effect depended on the ratio of BCR to Fc gamma RIIb cross-linking, In contrast to Fc gamma RIIb, the CD21/CD19 complex was shown to up-regulate B cell response by lowering the activation threshold, We have shown here that co-clustering of Fc gamma RIIb with CD19 inhibited the CD19-induced Ca2+ influx, Furthermore, the three party co-aggregation of Fc gamma RIIb with BCR and CD19 resulted in a decreased Ca2+ response, as compared to the BOB-plus CD19-induced one, indicating that Fc gamma RIIb may inhibit CD19-induced enhancement of B cell activation, On the basis of these data we suggest that IgG-containing and C3d-fixing immune complexes may down-regulate the B cell response by interfering with both BCR-and CD19-mediated Ca2+ mobilization.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
CD19
Fc gamma receptors
human B cells
regulation
signal transduction
Megjelenés:International Immunology. - 10 : 2 (1998), p. 141-146. -
További szerzők:Gergely János Sármay Gabriella
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4.

001-es BibID:BIBFORM054321
035-os BibID:PMID: 10382761
Első szerző:Koncz Gábor (biológus, immunológus)
Cím:Fcγ receptor-mediated inhibition of human B cell activation : the role of SHP-2 phosphatase / Gábor Koncz, Israel Pecht, János Gergely, Gabriella Sármay
Dátum:1999
ISSN:0014-2980
Megjegyzések:Co-clustering of the type II receptors binding the Fc part of IgG (Fc gamma RIIb) and B cell receptors results in the translocation of cytosolic, negative regulatory molecules to the phosphorylated immunoreceptor tyrosine-based inhibitory motif (P-ITIM) of the FcyRIIb. SH2 domain-containing protein tyrosine phosphatases (SHP-1 and SHP-2), and the polyphosphoinositol 5'-phosphatase (SHIP) have been reported earlier to bind to murine Fc gamma RIIb P-ITIM. However, neither the functional substrates of these enzymes, nor the mechanism of the inhibition are fully resolved. We show here that the human Fc gamma RIIb binds SHP-2 when co-clustered with the B cell receptors, whereas its synthetic P-ITIM peptide bindes SHP-2 and SHIP in lysates of the Burkitt's lymphoma cell line BL41. The P-ITIM peptide binding enhances SHP-2 activity resulting in dephosphorylation and release of P-ITIM-bound SHIP and She. Moreover, P-ITIM-bound SHP-2 dephosphorylates synthetic peptides corresponding to the sites of tyrosine phosphorylation on SHIP and She, indicating that these proteins are its potential substrates. Thus SHP-2-induced dephosphorylation may modulate the intracellular localization and/or activity of SHIP and She, thereby inhibiting further activation pathways which they mediate.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
SHP-2
Fc gamma RIIb
human
B cell
Megjelenés:European Journal of Immunology. - 29 : 6 (1999), p. 1980-1989. -
További szerzők:Pecht, Israel Gergely János Sármay Gabriella
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5.

001-es BibID:BIBFORM054319
035-os BibID:PMID: 11453982
Első szerző:Koncz Gábor (biológus, immunológus)
Cím:Co-clustering of Fcγ and B cell receptors induces dephosphorylation of the Grb2-associated binder 1 docking protein / Gábor Koncz, Gábor K. Tóth, Gyöngyi Bökönyi, György Kéri, Israel Pecht, David Medgyesi, János Gergely, Gabriella Sármay
Dátum:2001
ISSN:0014-2956 1432-1033
Megjegyzések:The immunoreceptor tyrosine-based inhibitory motif (ITIM) of human type Ilb Fc gamma receptor (Fc gamma RIIb) is phosphorylated on its tyrosine upon co-clustering with the B cell receptor (BCR). The phosphorylated ITIM (p-ITIM) binds to the SH2 domains of polyphosphoinositol 5-phosphatase (SHIP) and the tyrosine phosphatase, SHP-2. We investigated the involvement of the molecular complex composed of the phosphorylated SHIP and Fc gamma RIIb in the activation of SHP-2. As a model compound, we synthesized a bisphosphopeptide, combining the sequences of p-ITIM and the N-terminal tyrosine phosphorylated motif of SHIP with a flexible spacer. This compound bound to the recombinant SH2 domains of SHP-2 with high affinity and activated the phosphatase in an in vitro assay. These data suggest that the phosphorylated Fc gamma RII-SHIP complexes formed in the intact cells may also activate SHP-2. Grb2-associated binder 1 (Gab1) is a multisite docking protein, which becomes tyrosine-phosphorylated in response to various types of signaling, including BCR. In turn it binds to the SH2 domains of SHP-2, SHIP and the p85 subunit of phosphatidyl inositol 3-kinase (PtdIns3-K) and may regulate their activity. Gab1 is a potential substrate of SHP-2, thus its binding to Fc gamma RIIb may modify the Gab1-bound signaling complex. We show here that Gab1 is part of the multiprotein complex assembled by Fc gamma RIIb upon its co-clustering with BCR. Gab1 may recruit SH2 domain-containing molecules to the phosphorylated Fc gamma RIIb. SHP-2, activated upon the binding to Fc gamma RIIb-SHIP complex, partially dephosphorylates Gab1, resulting in the release of PtdIns3-K and ultimately in the inhibition of downstream activation pathways in BCR/Fc gamma RIIb co-aggregated cells.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
B-lymphocytes
Fc gamma receptors IIb
signal transduction
Megjelenés:European Journal of Biochemistry. - 268 : 14 (2001), p. 3898-3906. -
További szerzők:Tóth Gábor K. Bökönyi Gyöngyi Kéri György Pecht, Israel Medgyesi Dávid Gergely János Sármay Gabriella
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6.

001-es BibID:BIBFORM054308
035-os BibID:PMID: 12008033
Első szerző:Koncz Gábor (biológus, immunológus)
Cím:BCR mediated signal transduction in immature and mature B cells / Gábor Koncz, Csaba Bodor, Dorottya Kövesdi, Róbert Gáti, Gabriella Sármay
Dátum:2002
ISSN:0165-2478
Megjegyzések:Ligation of B cell receptors (BCR) on immature B cells may induce apoptosis, while in mature B cells it stimulates cell activation and growth. The signaling pathway regulating the differential functional response, death or survival of the B cell is not fully characterized. We have tested the intracellular signaling requirement of these processes using B cells isolated from the spleen of irradiated auto-reconstituted (transitional immature B cells) and untreated mice (mature B cells), respectively. We compared the BCR induced intracellular [Ca(2+)] transient, protein tyrosine phosphorylation and ERK phosphorylation, furthermore, the activation of Elk-1 and CREB transcription factors. The BCR induced rise of intracellular [Ca(2+)] did not significantly differ in the two populations, only a slight difference in the late phase of the response was observed. Immature B cells responded with a maximum tyrosine phosphorylation to a five times lower dose of anti-IgM compared to the mature population. Most importantly, we have found a significant difference in the tyrosine phosphorylation of the Gab family adaptor proteins, Gab1/2. In contrast to mature B cells, crosslinking of BCR on immature B cells did not induce tyrosine phosphorylation of Gab2, thus the Gab2-organized signal amplification complex could not be produced. Furthermore, we detected a significant difference in the kinetics of BCR induced ERK, Elk-1 and CREB phosphorylation. In immature B cells, ERK was transiently phosphorylated, ceasing after 120 min, while in mature cells, ERK phosphorylation was sustained. Elk-1 and CREB activation was also transient in immature B cells, followed the kinetics of ERK phosphorylation. The lack of sustained Erk1/2 activation suppresses the transcription factors necessary for the proliferation signal. Since ERK is regulated by the phosphorylated Gab1/2, these data demonstrate that BCR triggered phosphorylation and signal amplification of Gab1/2 is a critical step in a life or death decision of B cells.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Immunology Letters. - 82 : 1-2 (2002), p. 41-49. -
További szerzők:Bodor Csaba Kövesdi Dorottya Gáti Róbert Sármay Gabriella
Pályázati támogatás:Bolyai Janos Kutatasi Osztondij
Egyéb
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7.

001-es BibID:BIBFORM054309
035-os BibID:PMID: 11897497
Első szerző:Kövesdi Dorottya
Cím:Developmental differences in B cell receptor-induced signal transduction / Dorottya Kövesdi, Gábor Koncz, Roland Iványi-Nagy, Yael Caspi, Masamichi Ishiai, Tomohiro Kurosaki, János Gergely, Joseph Haimovich, Gabriella Sármay
Dátum:2002
ISSN:0898-6568
Megjegyzések:We have compared early signaling events at various stages of B cell differentiation using established mouse cell lines. Clustering of pre-B cell antigen receptor (BCR) or BCR induced the tyrosine phosphorylation of various proteins in all cells, although the phosphorylation pattern differed. In spite of the pre-BCR-induced tyrosine phosphorylation, we could not detect an intracellular Ca(2+) signal in pre-B cells. However. coclustering of the pre-BCR with CD19 did induce Ca(2+) mobilization. In contrast to the immature and mature B cells, where the B cell linker protein (BLNK) went through inducible tyrosine phosphorylation upon BCR clustering, we observed a constitutive tyrosine phosphorylation of BLNK in pre-B cell lines. Both BLNK and phospholipase C (PLC)gamma were raft associated in unstimulated pre-B cells, and this could not be enhanced by pre-BCR engagement, suggesting a ligand-independent PLC-gamma-mediated signaling. Further results indicate that the cell lines representing the immature stage are more sensitive to BCR-, CD19- and type II receptors binding the Fe part of IgG (FcgammaRIIb)mediated signals than mature B cells.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
B cell
development
receptors
signaling
tyrosine phosphorylation
Megjelenés:Cellular Signalling. - 14 : 6 (2002), p. 563-572. -
További szerzők:Koncz Gábor (1970-) (biológus, immunológus) Iványi-Nagy Roland Caspi, Yael Ishiai, Masamichi Kurosaki, Tomohiro Gergely János Haimovich, Joseph Sármay Gabriella
Pályázati támogatás:Bolyai János Kutatási Ösztöndíj
Egyéb
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8.

001-es BibID:BIBFORM054320
Első szerző:Kurucz István
Cím:Bacterially expressed human FcγRIIb is soluble and functionally active after in vitro refolding / István Kurucz, Ágnes Hilbert, Attila Kapus, Dávid Medgyesi, Gábor Koncz, Gabriella Sármay, Anna Erdei, János Gergely
Dátum:2000
ISSN:0165-2478
Megjegyzések:A recombinant soluble form of the human Fc gamma receptor was produced by engineering a cDNA construct containing the extracellular part of the mature protein. After expression in bacteria as inclusion body, the polypeptide was highly purified and was refolded in vitro with a method that was developed for the renaturation of immunoglobulin fragments. With this method oxidation of the disulfide bridges within the domains of the protein is done in the presence of an artificial 'chaperone' which protects the polypeptide molecules from unwanted protein-protein interactions thereby inhibiting the incorrect oxidation of the SH-groups, and misfolding of the protein. The refolded recombinant soluble Fc gamma RIIb showed several characteristics of the native receptor: (i) it was recognized by a series of monoclonal antibodies specific for, and in most cases produced against the native cell-surface receptor; (ii) it is bound to its ligand (the Fc-region of different immunoglobulins) under very diverse conditions; and (iii) it is competed strongly and specifically with the native cell surface receptor for both ligand and antibody binding in experiments with distinct read-outs; (iv) monoclonal antibodies produced against the recombinant protein specifically recognized Fc gamma RIIb on different cells. From these data it was concluded that the recombinant soluble Fc-receptor was in a native, functionally active form, and its function was not affected by the lack of glycosylation. (C) 2000 Elsevier Science B.V. All rights reserved.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
soluble Fc gamma receptors
bacterial expression
refolding
Megjelenés:Immunology Letters. - 75 : 1 (2000), p. 33-40. -
További szerzők:Hilbert Ágnes Kapus Attila Medgyesi Dávid Koncz Gábor (1970-) (biológus, immunológus) Sármay Gabriella Erdei Anna Gergely János
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9.

001-es BibID:BIBFORM054299
035-os BibID:PMID: 18950707
Első szerző:Maus Máté
Cím:Grb2 associated binder 2 couples B-cell receptor to cell survival / Máté Maus, Dávid Medgyesi, Dorottya Kövesdi, Dorottya Csuka, Gábor Koncz, Gabriella Sármay
Dátum:2009
ISSN:0898-6568
Megjegyzések:B-cell fate during maturation and the germinal center reaction is regulated through the strength and the duration of the B-cell receptor signal. Signaling pathways discriminating between apoptosis and survival in B cells are keys in understanding adaptive immunity. Gab2 is a member of the Gab/Dos adaptor protein family. It has been shown in several model systems that Gab/Dos family members may regulate both the anti-apoptotic PI3-K/Akt and the mitogenic Ras/MAPK pathways, still their role in B-cells have not been investigated in detail. Here we studied the role of Gab2 in B-cell receptor mediated signaling. We have shown that BCR crosslinking induces the marked phosphorylation of Gab2 through both Lyn and Syk kinases. Subsequently Gab2 recruits p85 regulatory subunit of PI3-K. and SHP-2. Our results revealed that Ig-alpha/Ig-beta, signal transducing unit of the B-cell receptor, may function as scaffold recruiting Gab2 to the signalosome. Overexpression of Gab2 in A20 cells demonstrated that Gab2 is a regulator of the PI3-K/Akt but not that of the Ras/MAPK pathway in B cells. Accordingly to the elevated Akt phosphorylation, overexpression of wild-type Gab2 in A20 cells suppressed Fas-mediated apoptosis, and enhanced BCR-mediated rescue from Fas-induced cell death. Although PH-domain has only a stabilizing effect on membrane recruitment of Gab2, it is indispensable in mediating its anti-apoptotic effect. (c) 2008 Elsevier Inc. All rights reserved.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
B-cell
Signaling
Gab2 adaptor/scaffolding protein
Phosphorylation
PH domain
Survival
Megjelenés:Cellular Signalling. - 21 : 2 (2009), p. 220-227. -
További szerzők:Medgyesi Dávid Kövesdi Dorottya Csuka Dorottya Koncz Gábor (1970-) (biológus, immunológus) Sármay Gabriella
Pályázati támogatás:OTKA-K60760
OTKA
GVOP-2004-05-3.1.1/3.00183
GVOP
NKFP-1-A/040/2004
Egyéb
CellKom REr/06
Egyéb
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Intézményi repozitóriumban (DEA) tárolt változat
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10.

001-es BibID:BIBFORM054307
035-os BibID:PMID: 15081531
Első szerző:Medgyesi Dávid
Cím:Functional consequences of a MAPK docking site on human FcγRIIb / Dávid Medgyesi, Rita Sárközi, Gábor Koncz, Krisztina Arató, Györgyi Váradi, Gábor K. Tóth, Gabriella Sármay
Dátum:2004
ISSN:0165-2478
Megjegyzések:Type IIb Fcgamma receptors (FcgammaRIIb) have a major role in regulating B cell activation. Upon its co-aggregation with the B cell receptors (BCR) via immune complexes FcgammaRIIb become phosphorylated on tyrosine within its immunoreceptor tyrosine based inhibitory motif (MM) and in turn recruit protein- and inositol phosphatases, inhibiting thereby signal transduction. The intracellular domain of the human FcgammaRIIb has a membrane proximal motif that is very similar to those of MAPK docking site in MAPK-interacting molecules. Additionally, in contrast to the mouse, a serine residue is located next to this motif that is a potential phosphorylation site for Ser/Thr kinases. Our aim was to study the role of the putative MAPK docking motif on FcgammaRIIb mediated function. We report here that MAPKs bind to FcgammaRIIb affinity purified from the detergent extracts of anti-IgM activated and BCR-FcgammaRIIb co-clustered B cells. We detected extracellular signal regulated kinase (ERK) activity in FcgammaRIIb immunoprecipitates and identified the bound proteins as 85, 44 and 42 kDa ERKs by Western blots. Active ERKs bound to the synthetic peptide representing the putative docking site of FcgammaRIIb on a Ser/Thr phosphatase dependent manner. The FcgammaRIIb-associated ERKs may phosphorylate the membrane proximal serine of the receptor. We examined the consequences of serine phosphorylation by comparing the proteins that interact with synthetic peptides comprising the combined sequences of the MAPK docking site and the ITIM either in phosphorylated or in non-phosphorylated forms. The results indicate that phosphorylation on serine modifies the binding of Lyn to FcgammaRIIb, thus might negatively regulate phosphorylation of ITIM. (C) 2003 Elsevier B.V. All rights reserved.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
B cell
Fc gamma RIIb
MAPK docking site
regulation
signalling
Megjelenés:Immunology Letters. - 92 : 1-2 (2004), p. 83-90. -
További szerzők:Sárközi Rita Koncz Gábor (1970-) (biológus, immunológus) Arató Krisztina Váradi Györgyi Tóth Gábor K. Sármay Gabriella
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11.

001-es BibID:BIBFORM054306
Első szerző:Medgyesi Dávid
Cím:Functional mapping of the FcγRII binding site on human IgG1 by synthetic peptides / Dávid Medgyesi, Katalin Uray, Krisztina Sallai, Ferenc Hudecz, Gábor Koncz, Jakub Abramson, Israel Pecht, Gabriella Sármay, János Gergely
Dátum:2004
ISSN:0014-2980
Megjegyzések:Receptors specific for the Fc part of IgG (FcgammaR) are expressed by several cell types and play diverse roles in immune responses. Impaired function of the activating and inhibitory FcgammaR may result in autoimmunity. Thus, the modulation of IgG-FcgammaR interaction can be a target for the development of treatments for some autoimmune and inflammatory diseases. This study addresses the localization and functional characterization of linear sequences in human IgG1 which bind to FcgammaRII. Peptides with overlapping sequences derived from the CH2 domain of human IgG1 between P(234) and S(298) were synthesized and used in binding and functional experiments. Binding of the peptides to FcgammaR was assayed in vitro and ex vivo, and peptides found to interact were functionally tested. The shortest effective peptide was T(216)-p(271) which bound to soluble recombinant Fc-gammaRIIb with K(d)=6x10(6) M(-1). The biotinylated peptides R(255)-p(271) and T(256)-p(271) complexed by avidin exhibited functional activity; they induced FcgammaRIIb-mediated inhibition of the BCR-triggered Ca(2+) response of human Burkitt lymphoma cells, and inflammatory cytokine production (TNF-alpha and IL-6) by the human monocyte cell line MonoMac. In conclusion, our results suggest that the selected peptides functionally represent the Fc-gammaRII-binding part of IgG1.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
IgG
Fc gamma Re
fc peptide
binding site
Megjelenés:European Journal of Immunology. - 34 : 4 (2004), p. 1127-1135. -
További szerzők:Uray Katalin Sallai Krisztina Hudecz Ferenc Koncz Gábor (1970-) (biológus, immunológus) Abramson, Jakub Pecht, Israel Sármay Gabriella Gergely János
Pályázati támogatás:AKP 2000-40 3,3
MTA
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Intézményi repozitóriumban (DEA) tárolt változat
Borító:

12.

001-es BibID:BIBFORM054348
035-os BibID:PMID: 7843241
Első szerző:Sármay Gabriella
Cím:The alternative splicing of human FcγRII mRNA is regulated by activation of B cells with mIgM cross-linking, interleukin-4, or phorbolester / Gabriella Sármay, Zoltán Rozsnyay, Gábor Koncz, Alla Danilkovich, János Gergely
Dátum:1995
ISSN:0014-2980
Megjegyzések:The human type two IgG binding receptors (Fc gamma RII) are encoded by three genes (Fc gamma RIIA, -B and C) resulting in at least six protein isoforms generated by alternative mRNA splicing. Surface expression of Fc gamma RTT has been shown to be modulated during B cell activation, although data characterizing the isoform(s) expressed are not available. The extracellular as well as the transmembrane domains of various Fc gamma RII are highly homologous. Only the intracellular domains vary between the different Fc gamma RII isoforms, suggesting differences in signal transduction. Using reverse transcriptase and polymerase chain reaction of mRNA obtained from resting tonsil B cells,we show that the majority of Fc gamma RII mRNA species to be of b2 type, although b1 type and a low level of Fc gamma RIIa type are also present. Culturing the cells for 18 h in the presence of 2.5 U/ml interleukin-4 or 10 mu g/ml affinity-purified anti-IgM F(ab')(2) fragments induced a switch in alternative splicing, resulting in a significant increase of Fc gamma RIIb1 mRNA expression, while the synthesis of Fc gamma RIIb2 mRNA was down-regulated. Stimulation of B cells with 100 ng/ml phorbol 12-myristate 13-acetate induced similar alteration, although only after 48-h treatment. The accumulation of Fc gamma RIIb1 and the reduction of both Fc gamma IIb2 and Fc gamma IIa mRNA in activated cells is accompanied by the enhanced expession of Fc gamma RII on the cell surface, representing most probably the Fc gamma RIIb1 isoform. Heat-aggregated IgG inhibited the anti-IgM-induced proliferation of resting but not that of activated B cells, suggesting that aggregation of Fc gamma RIIb2 constitutively expressed on resting B cells might be responsible for the prevention of inadequate activation of resting B cells.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
FC-GAMMA-RIIB
B CELLS
REGULATION
Megjelenés:European Journal of Immunology. - 25 : 1 (1995), p. 262-268. -
További szerzők:Rozsnyay Zoltán Koncz Gábor (1970-) (biológus, immunológus) Danilkovich, Alla Gergely János
Internet cím:Szerző által megadott URL
DOI
Intézményi repozitóriumban (DEA) tárolt változat
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