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| Defective assembly of the B-cell receptor chains accounts for its low expression in B-chronic lymphocytic leukaemia |
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| Author(s): Payelle-Brogard B, Magnac C, Alcover A, Roux P, Dighiero G |
| Source: BRITISH JOURNAL OF HAEMATOLOGY Volume: 118 Issue: 4 Pages: 976-985 Published: SEP 2002 |
| Times Cited: 20 References: 36 |
| Abstract: B-cell chronic lymphocytic leukaemia (B-CLL) characteristically displays low amounts of B-cell receptor (BCR), which mainly consists of the heterodimer CD79a/CD79b bound non-covalently with the surface immunoglobulin (SIg). This heterodimer is required for SIg expression and BCR signalling. To better define the mechanisms related to low BCR expression, we have investigated transcription, protein synthesis, assembly and transport of the BCR in B-CLL cells. Our results demonstrated that: (1) there was no major defect in transcriptional expression of the B29 (CD79b) gene; (2) the BCR components were intracellularly detected, thus adequately synthesized, in almost all patients; (3) neither a genetic defect in the transmembrane region of SIg, which associated with CD79a/CD79b, nor a genetic abnormality in the chaperone protein calnexin that is involved in folding and assembly of the BCR were found; (4) a constant defect in the assembly of IgM and CD79b chains occurred leading to abnormal accumulation of both chains in different intracellular compartments; (5) in a majority of CLL patients all of the nascent IgM failed to be processed into mature chains and remained unsuitable for transport. These findings demonstrated that a post-transcriptional defect located at the BCR intracellular assembly and/or trafficking levels could be involved in its low surface expression in B-CLL. |
| Document Type: Article |
| Language: English |
| Reprint Address: Payelle-Brogard, B (reprint author), Inst Pasteur, Unite Immunohematol & Immunopathol, 25 Rue Dr Roux, F-75724 Paris 15, France |
Addresses:
1. Inst Pasteur, Unite Immunohematol & Immunopathol, F-75724 Paris 15, France
2. Inst Pasteur, CNRS, URA 1960, Unite Biol Interact Cellulaires, Paris, France |
| Publisher: BLACKWELL PUBLISHING LTD, 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND |
| Subject Category: Hematology |
| IDS Number: 589EZ |
| ISSN: 0007-1048 |
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