1
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Renner K, Neumayer S, Talke Y, Buchtler S, Schmidbauer K, Nimmerjahn F, Lux A, Winter F, Salewski JN, Mack M. B cell modulation with anti-CD79bantibodies ameliorates experimental autoimmune encephalitis in mice. Eur J Immunol 2021; 52:656-668. [PMID: 34962287 DOI: 10.1002/eji.202149523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 11/15/2021] [Accepted: 12/28/2021] [Indexed: 11/12/2022]
Abstract
B cells play a major role in the pathogenesis of many autoimmune diseases like multiple sclerosis, rheumatoid arthritis or systemic lupus erythematosus. Depletion of B cells with anti-CD20 antibodies is an established therapy for multiple sclerosis. However, total B cell depletion will also affect regulatory B cells that are known to suppress autoimmune responses. In our studies we describe an alternative approach based on targeting of CD79b that induces only partial B cell depletion and achieves therapeutic effects by B cell modulation. Prophylactic and therapeutic treatment with an antibody against CD79b and also a deglycosylated variant of this antibody, lacking effector function like antibody-dependent cellular cytotoxicity or complement activation, significantly reduced the development and progression of experimental autoimmune encephalitis (EAE) in mice. Our data show that modulation of B cells via CD79b is equally effective as almost complete B cell depletion with anti-CD20 antibodies and may constitute an alternative approach to treat multiple sclerosis. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Kerstin Renner
- Department of Internal Medicine II - Nephrology, University Hospital Regensburg, Franz-Josef-Strauss Allee 11, Regensburg, 93042, Germany
| | - Sophia Neumayer
- Department of Internal Medicine II - Nephrology, University Hospital Regensburg, Franz-Josef-Strauss Allee 11, Regensburg, 93042, Germany
| | - Yvonne Talke
- Department of Internal Medicine II - Nephrology, University Hospital Regensburg, Franz-Josef-Strauss Allee 11, Regensburg, 93042, Germany
| | - Simone Buchtler
- Department of Internal Medicine II - Nephrology, University Hospital Regensburg, Franz-Josef-Strauss Allee 11, Regensburg, 93042, Germany
| | - Kathrin Schmidbauer
- Department of Internal Medicine II - Nephrology, University Hospital Regensburg, Franz-Josef-Strauss Allee 11, Regensburg, 93042, Germany
| | - Falk Nimmerjahn
- Division of Genetics, Department of Biology, University Erlangen-Nuernberg, Erwin-Rommel-Strasse 3, Erlangen, 91058, Germany
| | - Anja Lux
- Division of Genetics, Department of Biology, University Erlangen-Nuernberg, Erwin-Rommel-Strasse 3, Erlangen, 91058, Germany
| | - Frederike Winter
- Department of Internal Medicine II - Nephrology, University Hospital Regensburg, Franz-Josef-Strauss Allee 11, Regensburg, 93042, Germany.,Regensburg Center for Interventional Immunology, Franz-Josef-Strauss Allee 11, Regensburg, 93042, Germany
| | - Jan-Nicklas Salewski
- Department of Internal Medicine II - Nephrology, University Hospital Regensburg, Franz-Josef-Strauss Allee 11, Regensburg, 93042, Germany
| | - Matthias Mack
- Department of Internal Medicine II - Nephrology, University Hospital Regensburg, Franz-Josef-Strauss Allee 11, Regensburg, 93042, Germany.,Regensburg Center for Interventional Immunology, Franz-Josef-Strauss Allee 11, Regensburg, 93042, Germany
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2
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Kieckens E, Rybarczyk J, Li RW, Vanrompay D, Cox E. Potential immunosuppressive effects of Escherichia coli O157:H7 experimental infection on the bovine host. BMC Genomics 2016; 17:1049. [PMID: 28003017 PMCID: PMC5178093 DOI: 10.1186/s12864-016-3374-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 12/05/2016] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Enterohaemorrhagic Escherichia coli (EHEC), like E. coli O157:H7 are frequently detected in bovine faecal samples at slaughter. Cattle do not show clinical symptoms upon infection, but for humans the consequences after consuming contaminated beef can be severe. The immune response against EHEC in cattle cannot always clear the infection as persistent colonization and shedding in infected animals over a period of months often occurs. In previous infection trials, we observed a primary immune response after infection which was unable to protect cattle from re-infection. These results may reflect a suppression of certain immune pathways, making cattle more prone to persistent colonization after re-infection. To test this, RNA-Seq was used for transcriptome analysis of recto-anal junction tissue and ileal Peyer's patches in nine Holstein-Friesian calves in response to a primary and secondary Escherichia coli O157:H7 infection with the Shiga toxin (Stx) negative NCTC12900 strain. Non-infected calves served as controls. RESULTS In tissue of the recto-anal junction, only 15 genes were found to be significantly affected by a first infection compared to 1159 genes in the ileal Peyer's patches. Whereas, re-infection significantly changed the expression of 10 and 17 genes in the recto-anal junction tissue and the Peyer's patches, respectively. A significant downregulation of 69 immunostimulatory genes and a significant upregulation of seven immune suppressing genes was observed. CONCLUSIONS Although the recto-anal junction is a major site of colonization, this area does not seem to be modulated upon infection to the same extent as ileal Peyer's patches as the changes in gene expression were remarkably higher in the ileal Peyer's patches than in the recto-anal junction during a primary but not a secondary infection. We can conclude that the main effect on the transcriptome was immunosuppression by E. coli O157:H7 (Stx-) due to an upregulation of immune suppressive effects (7/12 genes) or a downregulation of immunostimulatory effects (69/94 genes) in the ileal Peyer's patches. These data might indicate that a primary infection promotes a re-infection with EHEC by suppressing the immune function.
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Affiliation(s)
- E. Kieckens
- Laboratory of Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
- Laboratory of Immunology and Animal Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - J. Rybarczyk
- Laboratory of Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
- Laboratory of Immunology and Animal Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - R. W. Li
- USDA-ARS, Bovine Functional Genomics Laboratory, Beltsville, MD USA
| | - D. Vanrompay
- Laboratory of Immunology and Animal Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - E. Cox
- Laboratory of Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
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3
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Levit-Zerdoun E, Becker M, Pohlmeyer R, Wilhelm I, Maity PC, Rajewsky K, Reth M, Hobeika E. Survival of Igα-Deficient Mature B Cells Requires BAFF-R Function. THE JOURNAL OF IMMUNOLOGY 2016; 196:2348-60. [PMID: 26843325 DOI: 10.4049/jimmunol.1501707] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/29/2015] [Indexed: 12/18/2022]
Abstract
Expression of a functional BCR is essential for the development of mature B cells and has been invoked in the control of their maintenance. To test this maintenance function in a new experimental setting, we used the tamoxifen-inducible mb1-CreER(T2) mouse strain to delete or truncate either the mb-1 gene encoding the BCR signaling subunit Igα or the VDJ segment of the IgH (H chain [HC]). In this system, Cre-mediated deletion of the mb-1 gene is accompanied by expression of a GFP reporter. We found that, although the Igα-deficient mature B cells survive for >20 d in vivo, the HC-deficient or Igα tail-truncated B cell population is short-lived, with the HC-deficient cells displaying signs of an unfolded protein response. We also show that Igα-deficient B cells still respond to the prosurvival factor BAFF in culture and require BAFF-R signaling for their in vivo maintenance. These results suggest that, under certain conditions, the loss of the BCR can be tolerated by mature B cells for some time, whereas HC-deficient B cells, potentially generated by aberrant somatic mutations in the germinal center, are rapidly eliminated.
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Affiliation(s)
- Ella Levit-Zerdoun
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; International Max Planck Research School for Molecular and Cellular Biology, 79108 Freiburg, Germany
| | - Martin Becker
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; International Max Planck Research School for Molecular and Cellular Biology, 79108 Freiburg, Germany
| | - Roland Pohlmeyer
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Isabel Wilhelm
- Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Palash Chandra Maity
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Klaus Rajewsky
- Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany; and
| | - Michael Reth
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany;
| | - Elias Hobeika
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany; Institute of Immunology, University Hospital Ulm, 89081 Ulm, Germany
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4
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Brühl H, Cihak J, Talke Y, Gomez MR, Hermann F, Goebel N, Renner K, Plachý J, Stangassinger M, Aschermann S, Nimmerjahn F, Mack M. B-cell inhibition by cross-linking CD79b is superior to B-cell depletion with anti-CD20 antibodies in treating murine collagen-induced arthritis. Eur J Immunol 2014; 45:705-15. [DOI: 10.1002/eji.201444971] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 10/21/2014] [Accepted: 11/26/2014] [Indexed: 12/26/2022]
Affiliation(s)
- Hilke Brühl
- Department of Internal Medicine I; University Hospital Regensburg; Regensburg Germany
| | - Josef Cihak
- Institute for Animal Physiology; University of Munich; Munich Germany
| | - Yvonne Talke
- Department of Internal Medicine II; University Hospital Regensburg; Regensburg Germany
| | | | - Fabian Hermann
- Department of Internal Medicine II; University Hospital Regensburg; Regensburg Germany
| | - Nicole Goebel
- Department of Internal Medicine II; University Hospital Regensburg; Regensburg Germany
| | - Kerstin Renner
- Department of Internal Medicine II; University Hospital Regensburg; Regensburg Germany
| | - Jiří Plachý
- Institute of Molecular Genetics; Czech Academy of Sciences; Prague Czech Republic
| | | | - Susanne Aschermann
- Institute of Genetics; University of Erlangen-Nuernberg; Erlangen Germany
| | - Falk Nimmerjahn
- Institute of Genetics; University of Erlangen-Nuernberg; Erlangen Germany
| | - Matthias Mack
- Department of Internal Medicine II; University Hospital Regensburg; Regensburg Germany
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5
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Tanaka T, Ichimura K, Sato Y, Takata K, Morito T, Tamura M, Kondo E, Ohara N, Yanai H, Sakai M, Takahashi S, Yoshino T. Frequent downregulation or loss of CD79a expression in plasma cell myelomas: Potential clue for diagnosis. Pathol Int 2009; 59:804-8. [DOI: 10.1111/j.1440-1827.2009.02448.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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6
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Okamoto S, Terao Y, Tamura Y, Hamada S, Kawabata S. Streptococcal immunoglobulin-binding protein Sib35 exerts stimulatory and mitogenic effects toward mouse B lymphocytes. FEMS Microbiol Lett 2008; 281:73-80. [DOI: 10.1111/j.1574-6968.2008.01078.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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7
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Cajiao I, Sargent R, Elstrom R, Cooke NE, Bagg A, Liebhaber SA. Igbeta(CD79b) mRNA expression in chronic lymphocytic leukaemia cells correlates with immunoglobulin heavy chain gene mutational status but does not serve as an independent predictor of clinical severity. Am J Hematol 2007; 82:712-20. [PMID: 17315213 DOI: 10.1002/ajh.20885] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The etiology of chronic lymphocytic leukemia (CLL) is poorly understood and its course is highly variable. Somatic hypermutation (SHM) of the immunoglobulin heavy chain (IgV(H)) gene and ZAP70 protein expression have been reported as prognostic indicators. However, these assays are not widely available and their concordance is imperfect. Thus a need exists to identify additional molecular determinants of CLL. The Igbeta (CD79b) subunit of the B cell antigen receptor is essential for B lymphocyte function. Defects in Igbeta expression are implicated in CLL pathogenesis. We have analyzed Igbeta mRNA expression in CLL cells in 40 consecutive patient samples. About 75% of the samples showed the expected decrease of Igbeta surface staining. Igbeta mRNA levels covered a wider range, did not correlate with Igbeta surface staining, but clearly distinguished the normal and CLL lymphocyte populations. Remarkably, Igbeta mRNA levels correlated strongly with SHM; Igbeta mRNA levels in CLL cells were significantly higher in patients with an unmutated IgV(H) gene when compared with those in whom IgV(H) was hypermutated (P = 0.008). In contrast, no correlation was observed between Igbeta mRNA levels and ZAP70 expression. Multiple parameters abstracted from chart reviews were used to estimate severity of CLL in each case. While severity correlated strongly with ZAP70 staining, and to a lesser extent with SHM status, there was no correlation with Igbeta mRNA levels. These data establish a strong linkage between Igbeta mRNA expression and SHM in CLL and highlight the complex relationships between biochemical parameters and clinical status in this disease.
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MESH Headings
- Adult
- Aged
- Aged, 80 and over
- Alternative Splicing/genetics
- CD79 Antigens/genetics
- CD79 Antigens/metabolism
- Cell Line
- Cell Membrane/metabolism
- Exons/genetics
- Female
- Gene Expression Regulation, Neoplastic/genetics
- Humans
- Immunoglobulin Heavy Chains/genetics
- Immunoglobulin Heavy Chains/immunology
- Immunohistochemistry
- Leukemia, Lymphocytic, Chronic, B-Cell/genetics
- Leukemia, Lymphocytic, Chronic, B-Cell/immunology
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- Lymphocytes/metabolism
- Male
- Middle Aged
- Mutation/genetics
- RNA, Messenger/genetics
- ZAP-70 Protein-Tyrosine Kinase/metabolism
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Affiliation(s)
- Isabela Cajiao
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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8
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Reichlin A, Gazumyan A, Nagaoka H, Kirsch KH, Kraus M, Rajewsky K, Nussenzweig MC. A B cell receptor with two Igalpha cytoplasmic domains supports development of mature but anergic B cells. J Exp Med 2004; 199:855-65. [PMID: 15024049 PMCID: PMC2212724 DOI: 10.1084/jem.20031140] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2003] [Accepted: 02/02/2004] [Indexed: 12/17/2022] Open
Abstract
B cell receptor (BCR) signaling is mediated through immunoglobulin (Ig)alpha and Igbeta a membrane-bound heterodimer. Igalpha and Igbeta are redundant in their ability to support early B cell development, but their roles in mature B cells have not been defined. To examine the function of Igalpha-Igbeta in mature B cells in vivo we exchanged the cytoplasmic domain of Igalpha for the cytoplasmic domain of Igbeta by gene targeting (Igbetac-->alphac mice). Igbetac-->alphac B cells had lower levels of surface IgM and higher levels of BCR internalization than wild-type B cells. The mutant B cells were able to complete all stages of development and were long lived, but failed to differentiate into B1a cells. In addition, Igbetac-->alphac B cells showed decreased proliferative and Ca2+ responses to BCR stimulation in vitro, and were anergic to T-independent and -dependent antigens in vivo.
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MESH Headings
- Animals
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- B-Lymphocytes/physiology
- Blotting, Southern
- Blotting, Western
- Bone Marrow/immunology
- Bromodeoxyuridine
- Calcium/metabolism
- Cell Differentiation/immunology
- Cell Differentiation/physiology
- Clonal Anergy/immunology
- DNA Primers
- Enzyme-Linked Immunosorbent Assay
- Flow Cytometry
- Genetic Vectors
- Immunoglobulin G/blood
- Immunoglobulin M/blood
- Mice
- Mice, Transgenic
- Protein Structure, Tertiary/physiology
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/metabolism
- Signal Transduction/physiology
- Spleen/immunology
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Affiliation(s)
- Amy Reichlin
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10021, USA
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9
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Li C, Siemasko K, Clark MR, Song W. Cooperative interaction of Ig and Ig of the BCR regulates the kinetics and specificity of antigen targeting. Int Immunol 2002. [DOI: 10.1093/intimm/14.10.1179] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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10
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Wienands J, Engels N. Multitasking of Ig-alpha and Ig-beta to regulate B cell antigen receptor function. Int Rev Immunol 2002; 20:679-96. [PMID: 11913945 DOI: 10.3109/08830180109045585] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Since their discovery as signaling subunits of the B cell antigen receptor (BCR), Ig-alpha and Ig-beta are discussed to serve either a redundant or distinct function for B cell development, maintenance, and activation. Dependent upon the experimental system that has been used to address this issue, evidence could be provided to support both possibilities. Only recently has it become clear that Ig-alpha and Ig-beta possess a unique signaling identity but that both together are required to orchestrate proper B cell function in vivo. Here we discuss some of the underlying mechanisms that may involve direct coupling to discrete subsets of BCR effector proteins, such as protein tyrosine kinases or the intracellular adaptor SLP-65/BLNK.
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Affiliation(s)
- J Wienands
- Department of Biochemistry and Molecular Immunology, University of Bielefeld, Germany.
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11
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Siemasko K, Skaggs BJ, Kabak S, Williamson E, Brown BK, Song W, Clark MR. Receptor-facilitated antigen presentation requires the recruitment of B cell linker protein to Igalpha. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:2127-38. [PMID: 11859098 DOI: 10.4049/jimmunol.168.5.2127] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Ags that cross-link the B cell Ag receptor are preferentially and rapidly delivered to the MHC class II-enriched compartment for processing into peptides and subsequent loading onto MHC class II. Proper sorting of Ag/receptor complexes requires the recruitment of Syk to the phosphorylated immunoreceptor tyrosine-based activation motif tyrosines of the B cell Ag receptor constituent Igalpha. We postulated that the Igalpha nonimmunoreceptor tyrosine-based activation motif tyrosines, Y(176) and Y(204), contributed to receptor trafficking. Igalpha(YDeltaF(176,204))/Igbeta receptors were targeted to late endosomes, but were excluded from the vesicle lumen and could not facilitate the presentation of Ag to T cells. Subsequent analysis demonstrated that phosphorylation of Y(176)/Y(204) recruited the B cell linker protein, Vav, and Grb2. Reconstitution of Igalpha(YDeltaF(176,204))/Igbeta with the B cell linker protein rescued both receptor-facilitated Ag presentation and entry into the MHC class II-enriched compartment. Thus, aggregation accelerates receptor trafficking by recruiting two separate signaling modules required for transit through sequential checkpoints.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Amino Acid Motifs
- Animals
- Antigen Presentation
- Antigens, CD/chemistry
- Antigens, CD/genetics
- Antigens, CD/metabolism
- B-Lymphocytes/immunology
- B-Lymphocytes/ultrastructure
- CD79 Antigens
- Carrier Proteins/physiology
- Cell Cycle Proteins
- Endocytosis
- Endosomes/metabolism
- GRB2 Adaptor Protein
- Mice
- Microscopy, Immunoelectron
- Models, Immunological
- Models, Molecular
- Phosphoproteins/physiology
- Phosphorylation
- Phosphotyrosine/physiology
- Proteins/metabolism
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-vav
- Receptors, Antigen, B-Cell/chemistry
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/metabolism
- Receptors, Antigen, B-Cell/physiology
- Recombinant Fusion Proteins/metabolism
- Tumor Cells, Cultured
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Affiliation(s)
- Karyn Siemasko
- Department of Medicine, Section of Rheumatology, University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA
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12
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Engels N, Wollscheid B, Wienands J. Association of SLP-65/BLNK with the B cell antigen receptor through a non-ITAM tyrosine of Ig-alpha. Eur J Immunol 2001; 31:2126-34. [PMID: 11449366 DOI: 10.1002/1521-4141(200107)31:7<2126::aid-immu2126>3.0.co;2-o] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The cytoplasmic adaptor protein SLP-65 (BLNK or BASH) is a critical downstream effector of the B cell antigen receptor (BCR). Tyrosine-phosphorylated SLP-65 assembles intracellular signaling complexes such as the Ca(2 +) initiation complex encompassing phospholipase C-gamma2 and Bruton's tyrosine kinase. It is, however, unclear how the SLP-65 signaling module can be recruited to the plasma membrane. Here we show that following B cell stimulation, SLP-65 associates directly with the BCR signaling subunit, the Ig-alpha / Ig-beta heterodimer. The interaction is mediated by the Src homology 2 domain of SLP-65 and the phosphorylated Ig-alpha tyrosine 204, which is located outside of the immunoreceptor tyrosine-based activation motif. Our data identify an unexpected BCR phosphorylation pattern and indicate that Ig-alpha has the capability to serve as transmembrane adaptor in BCR signaling.
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Affiliation(s)
- N Engels
- Institute of Biology III, University of Freiburg and Max Planck Institute of Immunobiology, Freiburg, Germany
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13
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Abstract
CD79 is composed of CD79a and CD79b components expressed almost exclusively on B cells and B-cell neoplasms. CD79a and CD79b expression precedes immunoglobulin (Ig) heavy-chain gene rearrangement and CD20 expression during B-cell ontogeny and disappears later than CD20 in the late (plasma cell) stage of B-cell differentiation. Therefore, antibodies to CD79a and CD79b are useful in the differential diagnosis of B-cell neoplasms from T-cell neoplasms or myeloid neoplasms, or L and H lymphocyte predominance Hodgkin's lymphoma from classic Hodgkin's lymphoma. In addition, CD79a and CD79b antibodies are useful markers in the diagnosis of precursor B-acute lymphoblastic leukemia (pre-B-ALL) because many of these tumors are negative for other B-cell markers, such as CD20 and CD45RA. Furthermore, for B-cell neoplasms, wherein CD20 expression is aberrantly lost, such as in diffuse large B-cell lymphoma, or for B-cell neoplasms after CD20-antibody therapy, CD79a may be used as a first-line B-cell marker for the diagnosis. In this review, the authors discuss the molecular biology of CD79 and the frequency and usefulness of CD79 expression in these neoplasms.
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MESH Headings
- Animals
- Antigens, CD/chemistry
- Antigens, CD/genetics
- Antigens, CD/metabolism
- B-Lymphocytes/immunology
- Biomarkers, Tumor
- Bone Marrow Cells/immunology
- CD79 Antigens
- Female
- Hodgkin Disease/immunology
- Humans
- Leukemia/immunology
- Leukemia, Myeloid/immunology
- Lymph Nodes/pathology
- Lymphoma, B-Cell/immunology
- Lymphoma, T-Cell/immunology
- Lymphoproliferative Disorders/immunology
- Male
- Receptors, Antigen, B-Cell/chemistry
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/metabolism
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Affiliation(s)
- P G Chu
- Division of Pathology, City of Hope National Medical Center, Duarte, California 91010, USA
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14
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Hsueh RC, Scheuermann RH. Tyrosine kinase activation in the decision between growth, differentiation, and death responses initiated from the B cell antigen receptor. Adv Immunol 2001; 75:283-316. [PMID: 10879287 DOI: 10.1016/s0065-2776(00)75007-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Immunoglobulin-containing receptors expressed on B lineage lymphocytes play critical roles in the development and function of the humoral arm of the immune system. The preB cell antigen receptor (preBCR) contains the immunoglobulin mu heavy chain (Ig mu) and signals to the preB cell that heavy chain rearrangement has been successful, a process termed heavy chain selection. The B cell antigen receptor (BCR) contains both Ig heavy and light chains and is expressed on immature and mature B cells before and after antigen encounter. Both receptor types from a complex with the Ig alpha and Ig beta proteins that link the predominantly extracellular Ig with intracellular signal transduction pathways. Signaling through the BCR induces different cellular responses depending on the nature of the signaling agent and the development stage of the target cell. These responses include clonal anergy and apoptotic deletion in immature B cells and survival, proliferation, and differentiation in mature B and preB cells. Several protein tyrosine kinases are activated rapidly following engagement of the BCR/preBCR complexes, including members of the Src family (Lyn and Blk), the Syk/ZAP70 family (Syk), and the Tec family (Btk). In this review, we discuss possible mechanisms by which engagement of these similar receptor complexes can give rise to different cellular responses and the role that these kinases play in this process.
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MESH Headings
- Agammaglobulinaemia Tyrosine Kinase
- Antibody Formation
- Antigens, CD/genetics
- Antigens, CD/immunology
- Apoptosis/physiology
- B-Lymphocyte Subsets/cytology
- B-Lymphocyte Subsets/enzymology
- B-Lymphocyte Subsets/immunology
- CD79 Antigens
- Cell Differentiation/physiology
- Cell Division/physiology
- Enzyme Activation
- Enzyme Precursors/physiology
- Genes, Immunoglobulin
- Hematopoietic Stem Cells/cytology
- Hematopoietic Stem Cells/immunology
- Humans
- Immune Tolerance
- Immunoglobulin Heavy Chains/genetics
- Immunologic Deficiency Syndromes/enzymology
- Immunologic Deficiency Syndromes/genetics
- Immunologic Deficiency Syndromes/immunology
- Intracellular Signaling Peptides and Proteins
- Lymphocyte Activation
- Phosphorylation
- Plasma Cells/cytology
- Plasma Cells/immunology
- Protein Processing, Post-Translational
- Protein-Tyrosine Kinases/physiology
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/physiology
- Recombinant Fusion Proteins/immunology
- Signal Transduction
- Syk Kinase
- ZAP-70 Protein-Tyrosine Kinase
- src Homology Domains
- src-Family Kinases/deficiency
- src-Family Kinases/genetics
- src-Family Kinases/physiology
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Affiliation(s)
- R C Hsueh
- Laboratory of Molecular Pathology, University of Texas Southwestern Medical Center, Dallas 75235, USA
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15
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Reichlin A, Hu Y, Meffre E, Nagaoka H, Gong S, Kraus M, Rajewsky K, Nussenzweig MC. B cell development is arrested at the immature B cell stage in mice carrying a mutation in the cytoplasmic domain of immunoglobulin beta. J Exp Med 2001; 193:13-23. [PMID: 11136817 PMCID: PMC2195879 DOI: 10.1084/jem.193.1.13] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The B cell receptor (BCR) regulates B cell development and function through immunoglobulin (Ig)alpha and Ig beta, a pair of membrane-bound Ig superfamily proteins, each of which contains a single cytoplasmic immunoreceptor tyrosine activation motif (ITAM). To determine the function of Ig beta, we produced mice that carry a deletion of the cytoplasmic domain of Ig beta (Ig beta Delta C mice) and compared them to mice that carry a similar mutation in Ig alpha (MB1 Delta C, herein referred to as Ig alpha Delta C mice). Ig beta Delta C mice differ from Ig alpha Delta C mice in that they show little impairment in early B cell development and they produce immature B cells that respond normally to BCR cross-linking as determined by Ca(2+) flux. However, Ig beta Delta C B cells are arrested at the immature stage of B cell development in the bone marrow and die by apoptosis. We conclude that the cytoplasmic domain Ig beta is required for B cell development beyond the immature B cell stage and that Ig alpha and Ig beta have distinct biologic activities in vivo.
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Affiliation(s)
- Amy Reichlin
- Laboratory of Molecular Immunology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10021
| | - Yun Hu
- Laboratory of Molecular Immunology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10021
| | - Eric Meffre
- Laboratory of Molecular Immunology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10021
| | - Hitoshi Nagaoka
- Laboratory of Molecular Immunology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10021
| | - Shiaoching Gong
- Laboratory of Molecular Immunology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10021
| | - Manfred Kraus
- Institute for Genetics, University of Cologne, 50931 Cologne, Germany
| | - Klaus Rajewsky
- Institute for Genetics, University of Cologne, 50931 Cologne, Germany
| | - Michel C. Nussenzweig
- Laboratory of Molecular Immunology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10021
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16
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Abstract
The B-cell antigen receptor (BCR) comprises membrane Igs (mIgs) and a heterodimer of Ig (CD79a) and Igβ (CD79b) transmembrane proteins, encoded by the mb-1 and B29 genes, respectively. These accessory proteins are required for surface expression of mIg and BCR signaling. B cells from chronic lymphocytic leukemia (B-CLL) frequently express low to undetectable surface Ig, as well as CD79b protein. Recent work described genetic aberrations affecting B29 expression and/or function in B-CLL. Because the prevalence of CLL is increased among first degree relatives, we analyzed the B29 gene in 10 families including 2 affected members each. A few silent or replacement mutations were observed at the genomic level, which never lead to truncated CD79b protein. Both members of the same family did not harbor the same mutations. However, a single silent base change in the B29 extracellular domain, corresponding to a polymorphism, was detected on 1 allele of most patients. These results indicate that the few mutations observed in the B29 gene in these patients do not induce structural abnormalities of the CD79b protein and thus do not account for its low surface expression in B-CLL. Furthermore, genetic factors were not implicated, because identical mutations were not observed among 2 members of the same family.
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17
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Kraus M, Saijo K, Torres RM, Rajewsky K. Ig-alpha cytoplasmic truncation renders immature B cells more sensitive to antigen contact. Immunity 1999; 11:537-45. [PMID: 10591179 DOI: 10.1016/s1074-7613(00)80129-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
To study the function of Ig-alpha in the selection of autoreactive B cells, we have analyzed mb-1 cytoplasmic truncation mutant mice (mb-1delta(c)/delta(c)), which coexpress transgenes encoding hen egg lysozyme (HEL) and HEL-specific immunoglobulin. We demonstrate that in the presence of soluble HEL (sHEL) and dependent on the mb-1delta(c) mutation, most immature B cells bearing the HEL-specific Ig transgene undergo rearrangements of endogenous kappa light chains, resulting in loss of HEL specificity. Moreover, immature B cells from Ig-alpha mutant mice respond to BCR cross-linking with an exaggerated and prolonged calcium response and induction of protein tyrosine phosphorylation. Our data imply a negative signaling role for Ig-alpha in immature B cells.
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MESH Headings
- Animals
- Antibody Specificity
- Antigens, CD/chemistry
- Antigens, CD/genetics
- Antigens, CD/immunology
- Apoptosis
- Autoantigens/genetics
- Autoantigens/immunology
- CD79 Antigens
- Calcium Signaling/immunology
- Clonal Deletion
- Crosses, Genetic
- Gene Rearrangement, B-Lymphocyte, Light Chain
- Immunoglobulin kappa-Chains/immunology
- Immunologic Capping
- Lymphocyte Activation/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Muramidase/genetics
- Muramidase/immunology
- Mutagenesis, Site-Directed
- Phosphorylation
- Protein Processing, Post-Translational/immunology
- Protein Structure, Tertiary
- Protein-Tyrosine Kinases/physiology
- Receptors, Antigen, B-Cell/chemistry
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/immunology
- Sequence Deletion
- Terminator Regions, Genetic
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Affiliation(s)
- M Kraus
- Department of Immunology, Institute for Genetics, University of Cologne, Germany.
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18
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Justement LB. Signal transduction via the B-cell antigen receptor: the role of protein tyrosine kinases and protein tyrosine phosphatases. Curr Top Microbiol Immunol 1999; 245:1-51. [PMID: 10533309 DOI: 10.1007/978-3-642-57066-7_1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
MESH Headings
- Adaptor Proteins, Signal Transducing
- Agammaglobulinaemia Tyrosine Kinase
- Animals
- Antigens/metabolism
- Antigens, CD/metabolism
- Antigens, CD/physiology
- Antigens, Differentiation, B-Lymphocyte/metabolism
- B-Lymphocytes/metabolism
- CD79 Antigens
- Calcium/metabolism
- Carrier Proteins/metabolism
- Cell Adhesion Molecules
- Enzyme Activation
- Enzyme Precursors/metabolism
- Gene Expression Regulation
- Humans
- Immunoglobulin M/metabolism
- Intracellular Signaling Peptides and Proteins
- Lectins
- Oncogene Proteins/metabolism
- Phosphoproteins/metabolism
- Phosphorylation
- Protein Tyrosine Phosphatase, Non-Receptor Type 11
- Protein Tyrosine Phosphatase, Non-Receptor Type 6
- Protein Tyrosine Phosphatases/metabolism
- Protein Tyrosine Phosphatases/physiology
- Protein-Tyrosine Kinases/metabolism
- Protein-Tyrosine Kinases/physiology
- Proteins/metabolism
- Proto-Oncogene Proteins c-vav
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/metabolism
- Receptors, Antigen, B-Cell/physiology
- Receptors, IgG/metabolism
- Sialic Acid Binding Ig-like Lectin 2
- Signal Transduction/immunology
- Signal Transduction/physiology
- Syk Kinase
- Type C Phospholipases/metabolism
- src-Family Kinases/metabolism
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Affiliation(s)
- L B Justement
- Department of Microbiology, University of Alabama at Birmingham 35294-3300, USA
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19
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Craxton A, Otipoby KL, Jiang A, Clark EA. Signal transduction pathways that regulate the fate of B lymphocytes. Adv Immunol 1999; 73:79-152. [PMID: 10399006 DOI: 10.1016/s0065-2776(08)60786-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- A Craxton
- Department of Microbiology, University of Washington, Seattle 98195, USA
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20
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Rickers A, Peters N, Badock V, Beyaert R, Vandenabeele P, Dörken B, Bommert K. Cleavage of transcription factor SP1 by caspases during anti-IgM-induced B-cell apoptosis. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 261:269-74. [PMID: 10103059 DOI: 10.1046/j.1432-1327.1999.00273.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Apoptosis is instrumental in the processes generating the diversity of the B-cell repertoire. Autoreactive B-cells are eliminated by anti-IgM crosslinking after encountering self-antigens, but precise mechanisms leading to B-cell apoptosis are still not well understood. We report here the cleavage of the transcription factor SP1 in the human Burkitt lymphoma cell line BL60 during anti-IgM-induced apoptosis. Western blot analysis revealed two cleavage products of approximately 68 kDa and 45 kDa after induction of apoptosis. Cleavage could be completely inhibited by zDEVD-fmk, an inhibitor specific for caspase 3-like proteases. In-vitro cleavage of recombinant SP1 by recombinant caspase 3 (CPP32) or caspase 7 (Mch 3) results in similar cleavage products as those observed in vivo. Recombinant caspase 6 (Mch 2) primarily generates a 68-kDa cleavage product, as observed after calcium ionophore (CaI) induced B-cell apoptosis. In contrast, caspase 1 (ICE) did not cleave SP1 in vitro. The time course of SP1 cleavage during anti-IgM-induced apoptosis is paralleled by an increase of caspase activity measured by DEVD-p-nitroanilide (DEVD-pNA) cleavage. DNA band-shift assays revealed a decrease in the intensity of the full length SP1/DNA complex and an increase in the intensity of a smaller complex due to the binding of one SP1 cleavage product. By Edman sequencing we could identify a caspase 3 cleavage site after Asp584 (D584AQPQAGR), generating a 22-kDa C-terminal SP1 protein fragment which still contains the DNA binding site. Our results show the cleavage of the human transcription factor SP1 in vivo and in vitro, underlining the central role of caspase 3-like proteases during the process of anti-IgM-induced apoptosis.
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Affiliation(s)
- A Rickers
- Medizinische Onkologie und Tumorimmunologie, Max Delbück Center for Molecular Medicine, Berlin-Buch, Germany
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21
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An Alternatively Spliced Form of CD79b Gene May Account for Altered B-Cell Receptor Expression in B-Chronic Lymphocytic Leukemia. Blood 1999. [DOI: 10.1182/blood.v93.7.2327] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractSeveral functional anomalies of B-chronic lymphocytic leukemia (B-CLL) cells may be explained by abnormalities of the B-cell receptor (BCR), a multimeric complex formed by the sIg homodimer and the noncovalently bound heterodimer Ig/Igβ (CD79a/CD79b). Because the expression of the extracellular Ig-like domain of CD79b has been reported to be absent in the cells of most CLL cases, we have investigated the molecular mechanisms that may account for this defect. Peripheral blood lymphocytes (PBL) from 50 patients and two cell lines (MEC1, MEC2) obtained from the PBL of one of them were studied. MEC1, MEC2, and 75% of CLL cases did not express detectable levels of the extracellular Ig-like domain of CD79b, which was nevertheless present in greater than 80% CD19+ cells from normal donors. In healthy subjects the expression of CD79b was equally distributed in CD5+ and CD5− B-cell subsets. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of CD79b RNA from all patients and from MEC1 and MEC2 cell lines consistently yielded two fragments of different size (709 bp and 397 bp). The 709-bp band corresponds to CD79b entire transcript; the 397-bp band corresponds to an alternatively spliced form lacking exon 3 that encodes the extracellular Ig-like domain. Both fragments were also visible in normal PBL. The expression of the 397-bp fragment was increased in normal activated B cells, while no difference was seen between CD5+ and CD5− B cells. To obtain a more accurate estimate of the relative proportions of the two spliced forms, a radioactive PCR was performed in 13 normal and 22 B-CLL samples and the results analyzed using a digital imager. The mean value of the CD79b to the CD79b internally deleted ratio was 0.64 ± 0.20 SD in normal donors and 0.44 ± 0.27 SD in B-CLL (P = .01). Direct sequencing of 397-bp RT-PCR products and of genomic DNA corresponding to exon 3 from MEC1, MEC2, their parental cells, and five fresh B-CLL samples did not show any causal mutation. Single-strand conformation polymorphism analysis of exon 3 performed in 18 additional B-CLL cases showed a single abnormal shift corresponding to a TGT → TGC polymorphic change at amino acid 122. We propose a role for the alternative splicing of CD79b gene in causing the reduced expression of BCR on the surface of B-CLL cells. As normal B cells also present this variant, the mechanism of CD79b posttranscriptional regulation might reflect the activation stage of the normal B cell from which B-CLL derives.
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22
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Alfarano A, Circosta P, Vallario A, Camaschella C, Indraccolo S, Amadori A, Caligaris-Cappio F. Alternative Splicing of CD79a (Igα) and CD79b (Igß Transcripts in Human B-CLL Cells. Curr Top Microbiol Immunol 1999. [DOI: 10.1007/978-3-642-60162-0_30] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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23
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Abstract
Abstract
Leukemic B cells in chronic lymphocytic leukemia (B-CLL) typically exhibit low or undetectable surface Ig. Because the B29 (CD79b and Igβ) and mb-1 (CD79a and Igα) gene products are required for surface Ig display in the B-cell receptor complex (BCR), we analyzed the expression of these genes in B-CLL cells. The majority (83%) of the randomly selected B-CLL patient samples analyzed exhibited low or undetectable surface BCR measured by μ heavy chain and B29 expression. Levels of mb-1 mRNA in these B-CLL samples with low surface BCR were similar to those in normal B cells. Among those with decreased surface expression, B29 mRNA was not detected in half of these B-CLL samples. The remaining B-CLL samples with diminished surface BCR contained normal levels of B29 mRNA. Further analysis of cDNA clones from the majority of these latter samples contained point mutations, insertions, or deletions that were largely located in the B29 transmembrane and cytoplasmic domains. These results indicate the occurrence of somatic mutations predicted to affect B29 expression and/or function in the majority of B-CLL and suggest that these aberrations underlie the diminished surface BCR display and loss of BCR signaling characteristic of this leukemia.
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