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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
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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