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Mediation of transitional B cell maturation in the absence of functional Bruton's tyrosine kinase. Sci Rep 2017; 7:46029. [PMID: 28378771 PMCID: PMC5380950 DOI: 10.1038/srep46029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/08/2017] [Indexed: 01/09/2023] Open
Abstract
X-linked immune-deficient (Xid) mice, carrying a mutation in Bruton’s tyrosine kinase (Btk), have multiple B cell lineage differentiation defects. We now show that, while Xid mice showed only mild reduction in the frequency of the late transitional (T2) stage of peripheral B cells, the defect became severe when the Xid genotype was combined with either a CD40-null, a TCRbeta-null or an MHC class II (MHCII)-null genotype. Purified Xid T1 and T2 B cells survived poorly in vitro compared to wild-type (WT) cells. BAFF rescued WT but not Xid T1 and T2 B cells from death in culture, while CD40 ligation equivalently rescued both. Xid transitional B cells ex vivo showed low levels of the p100 protein substrate for non-canonical NF-kappaB signalling. In vitro, CD40 ligation induced equivalent activation of the canonical but not of the non-canonical NF-kappaB pathway in Xid and WT T1 and T2 B cells. CD40 ligation efficiently rescued p100-null T1 B cells from neglect-induced death in vitro. These data indicate that CD40-mediated signals, likely from CD4 T cells, can mediate peripheral transitional B cell maturation independent of Btk and the non-canonical NF-kappaB pathway, and thus contribute to the understanding of the complexities of peripheral B cell maturation.
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Benkisser-Petersen M, Buchner M, Dörffel A, Dühren-von-Minden M, Claus R, Kläsener K, Leberecht K, Burger M, Dierks C, Jumaa H, Malavasi F, Reth M, Veelken H, Duyster J, Zirlik K. Spleen Tyrosine Kinase Is Involved in the CD38 Signal Transduction Pathway in Chronic Lymphocytic Leukemia. PLoS One 2016; 11:e0169159. [PMID: 28036404 PMCID: PMC5201248 DOI: 10.1371/journal.pone.0169159] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 12/13/2016] [Indexed: 11/29/2022] Open
Abstract
The survival and proliferation of CLL cells depends on microenvironmental contacts in lymphoid organs. CD38 is a cell surface receptor that plays an important role in survival and proliferation signaling in CLL. In this study we demonstrate SYK's direct involvement in the CD38 signaling pathway in primary CLL samples. CD38 stimulation of CLL cells revealed SYK activation. SYK downstream target AKT was subsequently induced and MCL-1 expression was increased. Concomitant inhibition of SYK by the SYK inhibitor R406 resulted in reduced activation of AKT and prevented upregulation of MCL-1. Moreover, short-term CD38 stimulation enhanced BCR-signaling, as indicated by increased ERK phosphorylation. CXCL12-dependent migration was increased after CD38 stimulation. Treating CLL cells with R406 inhibited CD38-mediated migration. In addition, we observed marked downregulation of CD38 expression for CLL cells treated with R406 compared to vehicle control. Finally, we observed a clear correlation between CD38 expression on CLL cells and SYK-inhibitor efficacy. In conclusion, our study provides deeper mechanistic insight into the effect of SYK inhibition in CLL.
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Affiliation(s)
- Marco Benkisser-Petersen
- Department of Hematology, Oncology and Stem cell transplantation, University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Maike Buchner
- Institute for Clinical Chemistry and Pathobiochemistry, Technische Universität München, München, Germany
| | - Arlette Dörffel
- Department of Internal Medicine V, Heidelberg University Hospital, Heidelberg, Germany
| | | | - Rainer Claus
- Department of Hematology, Oncology and Stem cell transplantation, University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Kathrin Kläsener
- BIOSS Centre for Biological Signalling Studies, Department of Molecular Immunology, Biology III, University of Freiburg, Freiburg, Germany
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Kerstin Leberecht
- BIOSS Centre for Biological Signalling Studies, Department of Molecular Immunology, Biology III, University of Freiburg, Freiburg, Germany
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Meike Burger
- Department of Hematology, Oncology and Stem cell transplantation, University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christine Dierks
- Department of Hematology, Oncology and Stem cell transplantation, University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Hassan Jumaa
- Department of Immunology, University Medical Center, Ulm, Germany
| | - Fabio Malavasi
- Department of Medical Sciences, Laboratory of Immunogenetics and CeRMS, University of Torino, and Transplant Immunology, Torino, Italy
| | - Michael Reth
- BIOSS Centre for Biological Signalling Studies, Department of Molecular Immunology, Biology III, University of Freiburg, Freiburg, Germany
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Hendrik Veelken
- Department of Hematology, Leiden University Medical Center, Leiden, The Netherlands
| | - Justus Duyster
- Department of Hematology, Oncology and Stem cell transplantation, University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Katja Zirlik
- Department of Hematology, Oncology and Stem cell transplantation, University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- * E-mail:
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Romero-Ramírez H, Morales-Guadarrama MT, Pelayo R, López-Santiago R, Santos-Argumedo L. CD38 expression in early B-cell precursors contributes to extracellular signal-regulated kinase-mediated apoptosis. Immunology 2015; 144:271-81. [PMID: 25155483 DOI: 10.1111/imm.12370] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 07/30/2014] [Accepted: 08/18/2014] [Indexed: 01/06/2023] Open
Abstract
CD38 is a 45,000 molecular weight transmembrane protein that is expressed in immature and mature lymphocytes. However, the expression and function of CD38 during B-cell differentiation in mice is poorly understood. Here, we report that CD38 is expressed from the earliest stages of B-cell development. Pre-pro-B, pro-B, pre-B and immature B cells from murine bone marrow all stained positive for CD38. Interestingly, CD38 expression increases with B-cell maturation. To assess the role of CD38 during B-cell maturation, CD38-deficient mice were analysed. CD38(-/-) mice showed a significant increase in both the frequency of B-lineage cells and the absolute numbers of pre-pro-B cells in bone marrow; however, no other differences were observed at later stages. CD38 cross-linking in Ba/F3 cells promoted apoptosis and marked extracellular signal-regulated kinase (ERK) phosphorylation, and these effects were reduced by treatment with the mitogen-activated protein kinase/ERK kinase inhibitor PD98059, and similar effects were observed in B-cell precursors from bone marrow. These data demonstrate that B-cell precursors in mouse bone marrow express functional CD38 and implicate the early ligation of CD38 in the ERK-associated regulation of the B-lineage differentiation pathway.
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Affiliation(s)
- Héctor Romero-Ramírez
- Department of Molecular Biomedicine, Centre for Research and Advanced Studies (CINVESTAV-IPN), Mexico City, Mexico; Department of Immunology, National School of Biological Sciences, IPN, Mexico City, Mexico
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Corneth OBJ, Klein Wolterink RGJ, Hendriks RW. BTK Signaling in B Cell Differentiation and Autoimmunity. Curr Top Microbiol Immunol 2015; 393:67-105. [PMID: 26341110 DOI: 10.1007/82_2015_478] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Since the original identification of Bruton's tyrosine kinase (BTK) as the gene defective in the primary immunodeficiency X-linked agammaglobulinemia (XLA) in 1993, our knowledge on the physiological function of BTK has expanded impressively. In this review, we focus on the role of BTK during B cell differentiation in vivo, both in the regulation of expansion and in the developmental progression of pre-B cells in the bone marrow and as a crucial signal transducer of signals downstream of the IgM or IgG B cell antigen receptor (BCR) in mature B cells governing proliferation, survival, and differentiation. In particular, we highlight BTK function in B cells in the context of host defense and autoimmunity. Small-molecule inhibitors of BTK have very recently shown impressive anti-tumor activity in clinical studies in patients with various B cell malignancies. Since promising effects of BTK inhibition were also seen in experimental animal models for lupus and rheumatoid arthritis, BTK may be a good target for controlling autoreactive B cells in patients with systemic autoimmune disease.
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Affiliation(s)
- Odilia B J Corneth
- Department of Pulmonary Medicine, Erasmus MC Rotterdam, Room Ee2251a, PO Box 2040, NL 3000, CA, Rotterdam, The Netherlands
| | - Roel G J Klein Wolterink
- Department of Pulmonary Medicine, Erasmus MC Rotterdam, Room Ee2251a, PO Box 2040, NL 3000, CA, Rotterdam, The Netherlands
| | - Rudi W Hendriks
- Department of Pulmonary Medicine, Erasmus MC Rotterdam, Room Ee2251a, PO Box 2040, NL 3000, CA, Rotterdam, The Netherlands.
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Abstract
Abstract
Several prognostic markers based on genetic, phenotypic, and molecular characteristics of chronic lymphocytic leukemia (CLL) B cells have emerged in the past decade. The clinical utility of these newer prognostic indicators, alone or in combination with each other and other clinical predictive systems, is still being determined. This chapter attempts to define biologic and molecular underpinnings of 3 sets of prognostic indicators in CLL: genetic abnormalities quantified by FISH and/or defined by exploratory sensitive molecular techniques, expression of specific proteins in or on CLL cells (ie, CD38, CD49d, and ZAP-70), and the IGHV mutation status of a CLL clone. Although not demonstrated conclusively, each probably reflects the biologic properties of the leukemic cells of individual CLL patients. This reflection may be direct, indicating a specific property of the CLL cell itself, or indirect, representing how the CLL cell interacts with the host's microenvironment. The new tyrosine kinase inhibitors that are currently in clinical trials support this interpretation. These and other biology-based indicators of patient clinical course and outcome can be used as starting points from which to understand and treat CLL.
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Hutcheson J, Vanarsa K, Bashmakov A, Grewal S, Sajitharan D, Chang BY, Buggy JJ, Zhou XJ, Du Y, Satterthwaite AB, Mohan C. Modulating proximal cell signaling by targeting Btk ameliorates humoral autoimmunity and end-organ disease in murine lupus. Arthritis Res Ther 2012; 14:R243. [PMID: 23136880 PMCID: PMC3674619 DOI: 10.1186/ar4086] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 08/13/2012] [Accepted: 10/09/2012] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION Systemic lupus erythematosus is a chronic autoimmune disease characterized by an abundance of autoantibodies against nuclear antigens. Bruton's tyrosine kinase (Btk) is a proximal transducer of the BCR signal that allows for B-cell activation and differentiation. Recently, selective inhibition of Btk by PCI-32765 has shown promise in limiting activity of multiple cells types in various models of cancer and autoimmunity. The aim of this study was to determine the effect of Btk inhibition by PCI-32765 on the development of lupus in lupus-prone B6.Sle1 and B6.Sle1.Sle3 mice. METHODS B6.Sle1 or B6.Sle1.Sle3 mice received drinking water containing either the Btk inhibitor PCI-32765 or vehicle for 56 days. Following treatment, mice were examined for clinical and pathological characteristics of lupus. The effect of PCI-32765 on specific cell types was also investigated. RESULTS In this study, we report that Btk inhibition dampens humoral autoimmunity in B6.Sle1 monocongenic mice. Moreover, in B6.Sle1.Sle3 bicongenic mice that are prone to severe lupus, Btk inhibition also dampens humoral and cellular autoimmunity, as well as lupus nephritis. CONCLUSIONS These findings suggest that partial crippling of cell signaling in B cells and antigen presenting cells (APCs) may be a viable alternative to total depletion of these cells as a therapeutic modality for lupus.
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Affiliation(s)
- Jack Hutcheson
- University of Texas Southwestern Medical Center, Department of Internal Medicine, Division of Rheumatic Diseases, 5323 Harry Hines Blvd., Dallas, TX 75390-8884, USA
| | - Kamala Vanarsa
- University of Texas Southwestern Medical Center, Department of Internal Medicine, Division of Rheumatic Diseases, 5323 Harry Hines Blvd., Dallas, TX 75390-8884, USA
| | - Anna Bashmakov
- University of Texas Southwestern Medical Center, Department of Internal Medicine, Division of Rheumatic Diseases, 5323 Harry Hines Blvd., Dallas, TX 75390-8884, USA
| | - Simer Grewal
- University of Texas Southwestern Medical Center, Department of Internal Medicine, Division of Rheumatic Diseases, 5323 Harry Hines Blvd., Dallas, TX 75390-8884, USA
| | - Deena Sajitharan
- University of Texas Southwestern Medical Center, Department of Internal Medicine, Division of Rheumatic Diseases, 5323 Harry Hines Blvd., Dallas, TX 75390-8884, USA
| | - Betty Y Chang
- Pharmacyclics, Inc., 995 East Arques Avenue, Sunnyvale, California 94085, USA
| | - Joseph J Buggy
- Pharmacyclics, Inc., 995 East Arques Avenue, Sunnyvale, California 94085, USA
| | - Xin J Zhou
- University of Texas Southwestern Medical Center, Department of Pathology, 5323 Harry Hines Blvd., Dallas, TX 75390-8884, USA
| | - Yong Du
- University of Texas Southwestern Medical Center, Department of Internal Medicine, Division of Rheumatic Diseases, 5323 Harry Hines Blvd., Dallas, TX 75390-8884, USA
| | - Anne B Satterthwaite
- University of Texas Southwestern Medical Center, Department of Internal Medicine, Division of Rheumatic Diseases, 5323 Harry Hines Blvd., Dallas, TX 75390-8884, USA
| | - Chandra Mohan
- University of Texas Southwestern Medical Center, Department of Internal Medicine, Division of Rheumatic Diseases, 5323 Harry Hines Blvd., Dallas, TX 75390-8884, USA
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Vences-Catalán F, Rajapaksa R, Levy S, Santos-Argumedo L. The CD19/CD81 complex physically interacts with CD38 but is not required to induce proliferation in mouse B lymphocytes. Immunology 2012; 137:48-55. [PMID: 22564057 DOI: 10.1111/j.1365-2567.2012.03602.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In B lymphocytes, the cell surface receptor CD38 is involved in apoptosis of immature B cells, proliferation and differentiation of mature B cells. Although CD38 has been establish as a receptor, its signaling has been only partially characterized. As a result of the lack of signaling motifs in the cytoplasmic domain, CD38 must use a co-receptor to induce signaling within the cell. Accordingly, CD38 has been associated with different receptors such as the T-cell receptor/CD3 complex on T cells, CD16 on natural killer cells and MHC class II molecules on monocytes. The CD19/CD81 complex has been proposed as a co-receptor for CD38 in human B lymphocytes, but little or no characterization has been performed in mice. In this study the contribution of the CD19/CD81 complex in murine CD38 signaling was evaluated. Proliferation assays were performed using CD19(-/-) or CD81(-/-) deficient mice; CFSE-labeled B lymphocytes from wild-type mice and CD19(-/-) , CD81(-/-) and CD38(-/-) deficient mice were stimulated with agonistic antibodies against CD38. Immunoprecipitation and immunofluorescence were also performed to detect protein-protein interactions. Our results indicate that the CD19/CD81 complex interacts with CD38 but this interaction is not required to induce proliferation in mouse B lymphocytes, suggesting that other receptors may contribute to the proliferation induced by CD38 in B lymphocytes.
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8
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Vences-Catalán F, Santos-Argumedo L. CD38 through the life of a murine B lymphocyte. IUBMB Life 2011; 63:840-6. [PMID: 21901817 DOI: 10.1002/iub.549] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 07/02/2011] [Indexed: 12/15/2022]
Abstract
CD38 is a 45 kDa transmembrane receptor expressed in B lymphocytes and other cells from the immune system. It is involved in apoptosis, cell activation, differentiation, and proliferation. CD38 has been used extensively to classify various subpopulations of lymphocytes in both humans and mice. It has also been used as a marker of poor prognosis in some lymphoid pathologies. However, CD38 is not a marker but rather an ectoenzyme and a receptor, where it performs several functions. The CD38 signaling pathway has only been partially studied in various cells of the immune system, where apparently the signaling is different depending on the lineage and differentiation state of the cell, leading to distinct outcomes. In this review, we provide an overview of well-established roles of CD38 signaling B lymphocytes from mice. We also discuss areas that need further clarification to get a broader image of how CD38 performs different functions in B cells and to understand its role in B lymphocyte biology under normal versus pathological conditions.
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Affiliation(s)
- Felipe Vences-Catalán
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Mexico
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Hendriks RW, Bredius RG, Pike-Overzet K, Staal FJ. Biology and novel treatment options for XLA, the most common monogenetic immunodeficiency in man. Expert Opin Ther Targets 2011; 15:1003-21. [PMID: 21635151 DOI: 10.1517/14728222.2011.585971] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION X-linked agammaglobulinemia (XLA) is the most common primary immunodeficiency in man, and is caused by a single genetic defect. Inactivating mutations in the Bruton's tyrosine kinase (BTK) gene are invariably the cause of XLA,. XLA is characterized by a differentiation arrest at the pre-B cell stage, the absence of immunoglobulins and recurrent bacterial infections, making it an insidious disease that gradually disables the patient, and can result in death due to chronic lung disease. Current treatment involves prophylactic antibiotics and immunoglobulin infusions, which are non-curative. This disease is a good candidate for curative hematopoietic stem cell (HSC)-based gene therapy, which could correct the B cell and myeloid deficiencies. AREAS COVERED This paper reviews the basic biology of BTK in B cell development, the clinical features of XLA, and the possibilities of gene therapy for XLA, covering the literature from 1995 to 2010. EXPERT OPINION Work from various laboratories demonstrates the feasibility of using gene-corrected HSCs to complement the immune defects of Btk-deficiency in mice. We propose that it is timely to start clinical programs to develop stem cell based therapy for XLA, using gene-corrected autologous HSC.
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Affiliation(s)
- Rudi W Hendriks
- Department of Pulmonary Medicine, Erasmus MC, Rotterdam, The Netherlands
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Malavasi F, Deaglio S, Funaro A, Ferrero E, Horenstein AL, Ortolan E, Vaisitti T, Aydin S. Evolution and function of the ADP ribosyl cyclase/CD38 gene family in physiology and pathology. Physiol Rev 2008; 88:841-86. [PMID: 18626062 DOI: 10.1152/physrev.00035.2007] [Citation(s) in RCA: 619] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The membrane proteins CD38 and CD157 belong to an evolutionarily conserved family of enzymes that play crucial roles in human physiology. Expressed in distinct patterns in most tissues, CD38 (and CD157) cleaves NAD(+) and NADP(+), generating cyclic ADP ribose (cADPR), NAADP, and ADPR. These reaction products are essential for the regulation of intracellular Ca(2+), the most ancient and universal cell signaling system. The entire family of enzymes controls complex processes, including egg fertilization, cell activation and proliferation, muscle contraction, hormone secretion, and immune responses. Over the course of evolution, the molecules have developed the ability to interact laterally and frontally with other surface proteins and have acquired receptor-like features. As detailed in this review, the loss of CD38 function is associated with impaired immune responses, metabolic disturbances, and behavioral modifications in mice. CD38 is a powerful disease marker for human leukemias and myelomas, is directly involved in the pathogenesis and outcome of human immunodeficiency virus infection and chronic lymphocytic leukemia, and controls insulin release and the development of diabetes. Here, the data concerning diseases are examined in view of potential clinical applications in diagnosis, prognosis, and therapy. The concluding remarks try to frame all of the currently available information within a unified working model that takes into account both the enzymatic and receptorial functions of the molecules.
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Affiliation(s)
- Fabio Malavasi
- Laboratory of Immunogenetics, Department of Genetics, Biology, and Biochemistry and Centro di Ricerca in Medicina Sperimentale, University of Torino Medical School, Torino, Italy.
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Abstract
CD38 is a surface receptor able to induce activation, proliferation, and survival of human and mouse lymphocytes; this molecule is expressed on the surface of both mature and immature B cells. In this work, the function of CD38 in the maturation of murine B lymphocytes in the spleen was analyzed. The results showed that CD38 is highly expressed on Transitional 2 (T2) B lymphocytes with an intermediate expression on Transitional 1 (T1) and mature follicular B cells (M). Correlating with a high expression of CD38, T2 cells are also larger and more granular than T1 or M B cells. T2 cells also showed high levels of other molecules, which indicate an activated phenotype. CD38 crosslinking induced proliferation and maturation of T2 B lymphocytes; in contrast, T1 subset died by apoptosis. Finally, CD38 stimulation of T2 B lymphocytes obtained from Btk-, Lyn-, or Fyn-deficient mice showed a defective differentiation; similarly, drugs interfering with PI3K or ERK decreased the proliferation or differentiation of this subset. This suggests that these molecules participate in the CD38 signaling pathway. As a whole, the results indicate that CD38 plays an important role in the regulation of B-cell maturation in the spleen.
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13
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Lund FE. Signaling properties of CD38 in the mouse immune system: enzyme-dependent and -independent roles in immunity. Mol Med 2007. [PMID: 17380200 DOI: 10.2119/2006-00099.lund] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 5th international CD38 meeting, held in Torino, Italy, spanned a range of topics from the role of CD38 as a signaling receptor in lymphocytic tumors to the importance of CD38-derived metabolites in NAD(+) metabolism, calcium signaling, and immune function. This meeting was particularly exciting as data were presented demonstrating that collaborative experiments between enzymologists, biochemists, cell biologists, immunologists, and clinicians have started to unravel the secrets of CD38 biology. It is now clear that all of the products of the CD38 enzyme reaction regulate calcium signal transduction in cell types as diverse as sea urchin oocytes and mammalian lymphocytes. It is also apparent that CD38 plays important immunomodulatory role(s), however there is still much debate on how CD38 mediates its immunoregulatory functions and whether the enzymatic products generated by CD38 are important for immunity. The data presented at this meeting have begun to resolve some of these controversies. First, CD38 regulates the function of leukocytes by enzyme-dependent and enzyme-independent mechanisms. Second, CD38 regulates inflammatory responses by modulating the activity of the responding leukocytes and by altering the activity of non-hematopoietic cells in the inflamed tissue. Finally, crosstalk between CD38 and other NAD(+) utilizing enzymes such as ART2, SIRT1, and PARP-1 impacts NAD(+) homeostasis, inflammation, and immunity. Thus, immunity is regulated by CD38 in multiple and unexpected ways and the new research challenge will be to determine whether we can exploit the complex biology of CD38 to therapeutically regulate the immune system.
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Affiliation(s)
- Frances E Lund
- Trudeau Institute, 154 Algonquin Ave., Saranac Lake, NY 12983, USA.
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Manjarrez-Orduño N, Moreno-García ME, Fink K, Santos-Argumedo L. CD38 cross-linking enhances TLR-induced B cell proliferation but decreases IgM plasma cell differentiation. Eur J Immunol 2007; 37:358-67. [PMID: 17274001 DOI: 10.1002/eji.200636453] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
It is becoming increasingly clear that the regulation of proliferation and differentiation of B cells to plasma cells involves the integration of a variety of intracellular signals provided by receptors of both the adaptive and innate immune system. The cross-linking of the surface molecule CD38 induces calcium mobilization, protein phosphorylation and NF-kappaB translocation into the nucleus, ultimately leading to proliferation and isotype switching toward IgG1. Here we describe (a) the effect on B cell activation of stimulating through both CD38 and Toll-like receptors 4, 7 and 9; and (b) that CD38 cross-linking increases the number of proliferating cells and the rate of proliferation in LPS-stimulated B cells by a Bruton's tyrosine kinase- and protein kinase C-dependent mechanism. In contrast, CD38 cross-linking reduces the number of cells committed to IgM plasma cell differentiation as measured by the number of CD138+ cells, antibody secretion, and the expression of PAX5, Bcl6 and Blimp-1. Since a putative ligand for CD38 is expressed by germinal center follicular dendritic cells, and CD38 expression is down-regulated in germinal center B cells, we speculate that CD38 might participate in the outcome of post-germinal center antibody responses.
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Affiliation(s)
- Nataly Manjarrez-Orduño
- Molecular Biomedicine Department, Centro de Investigación y de Estudios Avanzados del IPN, Mexico City, México
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15
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Lund FE. Signaling properties of CD38 in the mouse immune system: enzyme-dependent and -independent roles in immunity. MOLECULAR MEDICINE (CAMBRIDGE, MASS.) 2007; 12:328-33. [PMID: 17380200 PMCID: PMC1829203 DOI: 10.2119/2006–00099.lund] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Accepted: 12/07/2006] [Indexed: 11/06/2022]
Abstract
The 5th international CD38 meeting, held in Torino, Italy, spanned a range of topics from the role of CD38 as a signaling receptor in lymphocytic tumors to the importance of CD38-derived metabolites in NAD(+) metabolism, calcium signaling, and immune function. This meeting was particularly exciting as data were presented demonstrating that collaborative experiments between enzymologists, biochemists, cell biologists, immunologists, and clinicians have started to unravel the secrets of CD38 biology. It is now clear that all of the products of the CD38 enzyme reaction regulate calcium signal transduction in cell types as diverse as sea urchin oocytes and mammalian lymphocytes. It is also apparent that CD38 plays important immunomodulatory role(s), however there is still much debate on how CD38 mediates its immunoregulatory functions and whether the enzymatic products generated by CD38 are important for immunity. The data presented at this meeting have begun to resolve some of these controversies. First, CD38 regulates the function of leukocytes by enzyme-dependent and enzyme-independent mechanisms. Second, CD38 regulates inflammatory responses by modulating the activity of the responding leukocytes and by altering the activity of non-hematopoietic cells in the inflamed tissue. Finally, crosstalk between CD38 and other NAD(+) utilizing enzymes such as ART2, SIRT1, and PARP-1 impacts NAD(+) homeostasis, inflammation, and immunity. Thus, immunity is regulated by CD38 in multiple and unexpected ways and the new research challenge will be to determine whether we can exploit the complex biology of CD38 to therapeutically regulate the immune system.
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Affiliation(s)
- Frances E Lund
- Trudeau Institute, 154 Algonquin Ave., Saranac Lake, NY 12983, USA.
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16
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Shideman CR, Hu S, Peterson PK, Thayer SA. CCL5 evokes calcium signals in microglia through a kinase-, phosphoinositide-, and nucleotide-dependent mechanism. J Neurosci Res 2006; 83:1471-84. [PMID: 16547971 DOI: 10.1002/jnr.20839] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Microglia, the resident macrophages of the CNS, are responsible for the innate immune response in the brain and participate in the pathogenesis of certain neurodegenerative disorders. Chemokines initiate activation and migration of microglia. The beta-chemokine CCL5 induces an elevation in intracellular calcium concentration ([Ca(2+)](i)) in human microglia. Here, we examined the signal transduction pathway linking activation of chemokine receptor CCR5 to an elevation in [Ca(2+)](i) in cultured microglia by using pharmacological approaches in combination with Fura-2-based digital imaging. The CCL5-induced response required Janus kinase (Jak) activity and the stimulation of an inhibitory G protein. Multiple downstream signaling pathways were involved, including phosphatidylinositol 3-kinase (PI3K), Bruton's tyrosine kinase (Btk), and phospholipase C (PLC)-mediated release of Ca(2+) from inositol 1,4,5-trisphosphate (IP(3))-sensitive stores. Activation of both the kinase and the lipase pathways was required for eliciting the Ca(2+) response. However, the majority of the [Ca(2+)](i) increase was derived from sources activated by NAD metabolites. Cyclic ADP-ribose (cADPR) evoked Ca(2+) release from intracellular stores, and ADPR evoked Ca(2+) influx via a nimodipine-sensitive channel. Thus, a multistep cascade couples CCR5 activation to Ca(2+) increases in human microglia. Because changes in [Ca(2+)](i) affect chemotaxis, secretion, and gene expression, pharmacologic modulation of this pathway may alter inflammatory and degenerative processes in the CNS.
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MESH Headings
- Agammaglobulinaemia Tyrosine Kinase
- Calcium/metabolism
- Calcium Channels/drug effects
- Calcium Channels/metabolism
- Calcium Signaling/drug effects
- Calcium Signaling/immunology
- Cells, Cultured
- Chemokine CCL5
- Chemokines, CC/immunology
- Chemokines, CC/metabolism
- Chemokines, CC/pharmacology
- Cyclic ADP-Ribose/metabolism
- Encephalitis/immunology
- Encephalitis/metabolism
- Encephalitis/physiopathology
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Humans
- Immunity, Innate/immunology
- Immunologic Surveillance/immunology
- Inositol 1,4,5-Trisphosphate/metabolism
- Janus Kinase 1
- Microglia/drug effects
- Microglia/immunology
- Microglia/metabolism
- NAD/metabolism
- Nerve Degeneration/immunology
- Nerve Degeneration/metabolism
- Nerve Degeneration/physiopathology
- Phosphatidylinositol 3-Kinases/metabolism
- Protein-Tyrosine Kinases/metabolism
- Receptors, CCR5/agonists
- Receptors, CCR5/immunology
- Receptors, CCR5/metabolism
- Signal Transduction/drug effects
- Signal Transduction/immunology
- Signal Transduction/physiology
- Type C Phospholipases/metabolism
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Affiliation(s)
- C R Shideman
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, USA
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17
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Moreno-García ME, López-Bojórques LN, Zentella A, Humphries LA, Rawlings DJ, Santos-Argumedo L. CD38 signaling regulates B lymphocyte activation via a phospholipase C (PLC)-gamma 2-independent, protein kinase C, phosphatidylcholine-PLC, and phospholipase D-dependent signaling cascade. THE JOURNAL OF IMMUNOLOGY 2005; 174:2687-95. [PMID: 15728476 DOI: 10.4049/jimmunol.174.5.2687] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The CD38 cell surface receptor is a potent activator for splenic, B lymphocytes. The molecular mechanisms regulating this response, however, remain incompletely characterized. Activation of the nonreceptor tyrosine kinase, Btk, is essential for CD38 downstream signaling function. The major Btk-dependent substrate in B cells, phospholipase C-gamma2 (PLC-gamma2), functions to generate the key secondary messengers, inositol-1,4,5 trisphosphate and diacylglycerol. Surprisingly, CD38 ligation results in no detectable increase in phosphoinositide metabolism and only a minimal increase in cytosolic calcium. We hypothesized that Btk functioned independently of PLC-gamma2 in the CD38 signaling pathway. Accordingly, we demonstrate that CD38 cross-linking does not result in the functional phosphorylation of PLC-gamma2 nor an increase in inositol-1,4,5 trisphosphate production. Furthermore, splenic B cells exhibit a normal CD38-mediated, proliferative response in the presence of the phosphoinositide-PLC inhibitor, U73122. Conversely, protein kinase C (PKC) beta-deficient mice, or PKC inhibitors, indicated the requirement for diacylglycerol-dependent PKC isoforms in this pathway. Loss of PKC activity blocked CD38-dependent, B cell proliferation, NF-kappaB activation, and subsequent expression of cyclin-D2. These results suggested that an alternate diacylglycerol-producing phospholipase must participate in CD38 signaling. Consistent with this idea, CD38 increased the enzymatic activity of the phosphatidylcholine (PC)-metabolizing enzymes, PC-PLC and phospholipase D. The PC-PLC inhibitor, D609, completely blocked CD38-dependent B cell proliferation, IkappaB-alpha degradation, and cyclin-D2 expression. Analysis of Btk mutant B cells demonstrated a partial requirement for Btk in the activation of both enzymes. Taken together, these data demonstrate that CD38 initiates a novel signaling cascade leading to Btk-, PC-PLC-, and phospholipase D-dependent, PLC-gamma2-independent, B lymphocyte activation.
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Affiliation(s)
- Miguel E Moreno-García
- Departments of Cell Biology, Centro de Investigación y Estudios Avanzados, Mexico D.F. Mexico
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18
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Sandoval-Montes C, Santos-Argumedo L. CD38 is expressed selectively during the activation of a subset of mature T cells with reduced proliferation but improved potential to produce cytokines. J Leukoc Biol 2004; 77:513-21. [PMID: 15618297 DOI: 10.1189/jlb.0404262] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
CD38 is an approximately 45-kDa type II transmembrane glycoprotein expressed by hematopoietic and nonhematopoietic cells. Its surface expression is under complex control and varies during lymphocyte development, activation, and differentiation, suggesting an important role in these processes. Murine CD38 has been mainly characterized on B lymphocytes, and in humans, the molecule has been studied in T cells. This paper provides evidences that murine CD38 is regulated tightly during T cell activation and differentiation. On the periphery, a subset of mature T lymphocytes was identified by the expression of CD38. These cells showed an activated phenotype; they were larger and more granular than their negative counterparts. In accord with this observation, in vitro-activated T cells up-regulated CD38. Memory T lymphocytes also were CD38-positive. It is interesting that T cells expressing high levels of CD38 had a reduced, proliferative capacity but displayed an improved potential to produce interleukin-2 and interferon-gamma, suggesting a role of this molecule during T cell activation and differentiation.
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Affiliation(s)
- Claudia Sandoval-Montes
- Departamento de Biomedicina Molecular, Centro de Investigación y Estudios Avanzados, IPN, Mexico
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19
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Sacristán C, Tussié-Luna MI, Logan SM, Roy AL. Mechanism of Bruton's Tyrosine Kinase-mediated Recruitment and Regulation of TFII-I. J Biol Chem 2004; 279:7147-58. [PMID: 14623887 DOI: 10.1074/jbc.m303724200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
TFII-I is a ubiquitously expressed multifunctional transcription factor with broad biological roles in transcription and signal transduction in a variety of cell types. We and others have shown that TFII-I can interact physically and functionally with Bruton's tyrosine kinase (Btk), a hematopoietic non-receptor protein tyrosine kinase that is critical for B lymphocyte development. Although TFII-I-Btk interactions are impaired in B cells from X-linked immunodeficient mice, the precise molecular determinants governing TFII-I-Btk complex formation remain unknown. To this end, we have conducted a structural analysis of TFII-I-Btk interactions by using a panel of TFII-I mutants. These studies have revealed that a region within the N-terminal 90 amino acids of TFII-I, which includes a putative leucine zipper motif, is primarily responsible for its interaction with Btk. Mutations in the leucine zipper region itself were not sufficient to abrogate binding of TFII-I to Btk, suggesting that regions/residues outside the leucine zipper are responsible for such interactions. Because the first 90 amino acids of TFII-I are required for its dimerization, we propose that Btk tethers TFII-I to the cytoplasm by preventing its dimerization and its subsequent nuclear localization. We further examined the requirement of tyrosine phosphorylation for TFII-I-Btk complex formation. Our data showed that Src-dependent tyrosine phosphorylation sites in TFII-I are not targeted by Btk, suggesting that multiple kinases can independently target TFII-I via distinct signaling pathways. Our results provide a beginning step toward understanding the functional importance of the TFII-I-Btk pathway in B cell signaling and gene expression.
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Affiliation(s)
- Catarina Sacristán
- Department of Pathology, Program in Immunology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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20
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Whyburn LR, Halcomb KE, Contreras CM, Lowell CA, Witte ON, Satterthwaite AB. Reduced dosage of Bruton's tyrosine kinase uncouples B cell hyperresponsiveness from autoimmunity in lyn-/- mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:1850-8. [PMID: 12902486 DOI: 10.4049/jimmunol.171.4.1850] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The development of autoimmunity is correlated with heightened sensitivity of B cells to B cell Ag receptor (BCR) cross-linking. BCR signals are down-regulated by Lyn, which phosphorylates inhibitory receptors. lyn(-/-) mice have reduced BCR signaling thresholds and develop autoantibodies, glomerulonephritis, splenomegaly due to myeloid hyperplasia, and increased B-1 cell numbers. Bruton's tyrosine kinase (Btk), a critical component of BCR signaling pathways, is required for autoantibody production in lyn(-/-) mice. It is unclear whether Btk mediates autoimmunity at the level of BCR signal transduction or B cell development, given that lyn(-/-)Btk(-/-) mice have a severe reduction in conventional B and B-1 cell numbers. To address this issue, we crossed a transgene expressing a low dosage of Btk (Btk(low)) in B cells to lyn(-/-)Btk(-/-) mice. Conventional B cell populations were restored to levels similar to those in lyn(-/-) mice. These cells were as hypersensitive to BCR cross-linking as lyn(-/-) B cells as measured by proliferation, Ca(2+) flux, and activation of extracellular signal-regulated kinase and Akt. However, lyn(-/-)Btk(low) mice did not produce anti-ssDNA, anti-dsDNA, anti-histone, or anti-histone/DNA IgM or IgG. They also lacked B-1 cells and did not exhibit splenomegaly. Thus, B cell hyperresponsiveness is insufficient for autoimmunity in lyn(-/-) mice. These studies implicate B-1 and/or myeloid cells as key contributors to the lyn(-/-) autoimmune phenotype.
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MESH Headings
- Agammaglobulinaemia Tyrosine Kinase
- Animals
- Autoantibodies/biosynthesis
- B-Lymphocyte Subsets/enzymology
- B-Lymphocyte Subsets/immunology
- B-Lymphocyte Subsets/pathology
- Cell Division/genetics
- Cell Division/immunology
- Cross-Linking Reagents/metabolism
- Gene Dosage
- Lymphocyte Activation/genetics
- Lymphopenia/enzymology
- Lymphopenia/genetics
- Lymphopenia/immunology
- Lymphopenia/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Oncogene Proteins, Viral/deficiency
- Oncogene Proteins, Viral/genetics
- Oncogene Proteins, Viral/physiology
- Protein-Tyrosine Kinases/deficiency
- Protein-Tyrosine Kinases/genetics
- Protein-Tyrosine Kinases/physiology
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/metabolism
- Signal Transduction/genetics
- Signal Transduction/immunology
- Splenomegaly/genetics
- Splenomegaly/immunology
- Transgenes/immunology
- src-Family Kinases/deficiency
- src-Family Kinases/genetics
- src-Family Kinases/physiology
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Affiliation(s)
- Lindsey R Whyburn
- Harold Simmons Arthritis Research Center, Department of Internal Medicine and Center for Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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21
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Cabatingan MS, Schmidt MR, Sen R, Woodland RT. Naive B lymphocytes undergo homeostatic proliferation in response to B cell deficit. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:6795-805. [PMID: 12471111 DOI: 10.4049/jimmunol.169.12.6795] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Naive peripheral B cells are maintained in sufficient numbers and diversity to mount effective immune responses against infectious agents. However, the size and repertoire of this B cell pool is constantly diminished by normal cell turnover and Ag activation. Homeostatic (Ag-independent) proliferation in response to B cell depletion is one mechanism to compensate for this cell loss. We have used purified CFSE-labeled B cells and an adoptive transfer model system to show that immature and mature B cells divide in a variety of B cell-deficient (scid, xid, IL-7(-/-), and sublethally irradiated) hosts. Homeostatic B cell proliferation is T cell independent, and B cells that have replicated by this mechanism retain the antigenic phenotype of naive B cells. Replication is significantly reduced in B cell-sufficient normal or B cell-reconstituted immunodeficient recipients by the action of competing mature follicular B cells. Using xid mice and transcription factor knockouts, we show that the activation signal(s) that lead to homeostatic B cell proliferation require Bruton's tyrosine kinase; however, c-Rel, a Bruton's tyrosine kinase-induced NF-kappaB/Rel transcription factor critical for Ag and mitogen stimulation, is dispensable, indicating the uniqueness of this activation pathway. Survival and replication signals can also be separated, because the transcription factor p50 (NF-kappaB1), which is required for the survival of peripheral B cells, is not necessary for homeostatic replication. Homeostatic B cell proliferation provides an Ag-independent mechanism for the maintenance and expansion of naive B cells selected into the mature B cell pool.
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Affiliation(s)
- Mark S Cabatingan
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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22
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Gao W, Wortis HH, Pereira MA. The Trypanosoma cruzi trans-sialidase is a T cell-independent B cell mitogen and an inducer of non-specific Ig secretion. Int Immunol 2002; 14:299-308. [PMID: 11867566 DOI: 10.1093/intimm/14.3.299] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Polyclonal lymphocyte activation and hypergammaglobulinemia characterize the acute phase of many parasitic diseases, including Chagas' disease, a debilitating condition caused by Trypanosoma cruzi. Polyclonal lymphocyte activation correlates with disease susceptibility inT. cruzi infection. Thus, identifying factors that drive such reactivities should provide insight into mechanisms of parasite evasion from host immunity and of disease pathogenesis. Sensitization of mice with small doses of T. cruzi trans-sialidase (TS) turns the mice into highly susceptible hosts to T. cruzi. In addition, TS heterologously expressed in Leishmania major greatly enhances virulence of the parasite to mice. In attempt to study the mechanism of TS-induced virulence, we found that TS and its C-terminal long tandem repeat (LTR) are T-independent polyclonal activators for mouse B cells. While B cells deficient/defective in L-6, CD40 or Toll-like receptor-4 are similarly activated by TS as compared to wild-type cells, B cells from Bruton's tyrosine kinase-defective X-linked immunodeficient mice are remarkably insensitive to TS activation. TS-induced B cell activation in vitro is accompanied by Ig secretion independent of T cells. Furthermore, administration of TS into normal mice leads to non-specific Ig secretion that peaks 4-6 days after injection. Thus TS, through its LTR, induces abnormal polyclonal B cell activation and Ig secretion, which could explain in part its virulence-enhancing activity.
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Affiliation(s)
- Wenda Gao
- Parasitology Research Center, Department of Pathology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
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23
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Cancro MP, Sah AP, Levy SL, Allman DM, Schmidt MR, Woodland RT. xid mice reveal the interplay of homeostasis and Bruton's tyrosine kinase-mediated selection at multiple stages of B cell development. Int Immunol 2001; 13:1501-14. [PMID: 11717191 DOI: 10.1093/intimm/13.12.1501] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human X-linked agammaglobulinemia (XLA) and murine X-linked immune defect (XID) are both immunodeficiencies mediated by mutations in Bruton's tyrosine kinase (Btk), yet the developmental stage(s) affected remain controversial. To further refine the placement of the XID defect(s), we used bromodeoxyuridine labeling to determine turnover, production and transition rates of developing B cell subsets in normal, xid and xid mice expressing a human Bcl-2 transgene (xid/bcl-2). We find the xid mutation manifest at two stages of B cell development. The first is early, reducing pre-B cell production by restricting pro-B to pre-B cell transit. Surprisingly, this impairment is offset by increased survival of cells progressing from the pre- to immature B cell pool, suggesting that Btk-independent homeostatic mechanisms act to maintain this compartment. The second point of action is late, substantially reducing mature B cell production. Together, these findings reconcile apparent discrepancies in the developmental stage affected by the murine versus human lesions and suggest previously unappreciated homeostatic processes that act at the pre-B to immature B cell transition. Finally, Btk likely functions differently at these two checkpoints, since ectopic Bcl-2 expression fails to directly complement the early xid lesion, yet reverses the defect impeding final B cell maturation.
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Affiliation(s)
- M P Cancro
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, 36th and Hamilton Walk, Philadelphia, PA 19104-6082, USA
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24
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Affiliation(s)
- S Tsukada
- Department of Molecular Medicine, Osaka University Medical School, Yamadaoka, Suita City, Osaka 565-0871, Japan
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25
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Egloff AM, Desiderio S. Identification of Phosphorylation Sites for Bruton's Tyrosine Kinase within the Transcriptional Regulator BAP/TFII-I. J Biol Chem 2001; 276:27806-15. [PMID: 11373296 DOI: 10.1074/jbc.m103692200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bruton's tyrosine kinase (Btk), a member of the Tec family of cytosolic kinases, is essential for B cell development and function. BAP/TFII-I, a protein implicated in transcriptional regulation, is associated with Btk in B cells and is transiently phosphorylated on tyrosine following B cell receptor engagement. BAP/TFII-I is a substrate for Btk in vitro and is hyperphosphorylated on tyrosine upon coexpression with Btk in mammalian cells. In an effort to understand the physiologic consequences of BAP/TFII-I tyrosine phosphorylation following B cell receptor stimulation, site-directed mutagenesis and phosphopeptide mapping were used to locate the predominant sites of BAP/TFII-I phosphorylation by Btk in vitro. These residues, Tyr248, Tyr357, and Tyr462, were also found to be the major sites for Btk-dependent phosphorylation of BAP/TFII-I in vivo. Residues Tyr357 and Tyr462 are contained within the loop regions of adjacent helix-loop-helix-like repeats within BAP/TFII-I. Mutation of either Tyr248, Tyr357, or Tyr462 to phenylalanine reduced transcription from a c-fos promoter relative to wild-type BAP/TFII-I in transfected COS-7 cells, consistent with the interpretation that phosphorylation at these sites contributes to transcriptional activation. Phosphorylation of BAP/TFII-I by Btk may link engagement of receptors such as surface immunoglobulin to modulation of gene expression.
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Affiliation(s)
- A M Egloff
- Department of Molecular Biology and Genetics and Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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26
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Abstract
Analysis of expression of CD38, CD45R (B220), IgM and IgD on splenic B lymphocytes from mice of different ages demonstrated CD38 on both immature (B220(+), BCR(-)) and mature (B220(+), BCR(+)) B lymphocytes. Similarly, CD38 is expressed as early as B220 on the surface of progenitor B cells in the bone marrow. In spite of expressing of CD38 and IgM, neonatal B cells, in contrast to the adult, failed to proliferate to either anti-CD38 or anti-IgM cross-linking when IL-4 was present. They did, however, respond to LPS and anti-CD40, and by 2 weeks of age they began to respond to anti-CD38 and anti-IgM, reaching adult B cell levels by 4 weeks. Although the distribution of CD38 on adult B cells from most different lymphoid compartments was broadly similar, significantly higher levels of CD38 were expressed on peritoneal B lymphocytes. A detailed analysis, using IgM / IgD ratio and staining with anti-CD5 confirmed that B1 lymphocytes were expressing a high level of CD38. Interestingly, both immature B cells and peritoneal B1 lymphocytes were unresponsive to anti-CD38. However, they were activated by LPS or anti-CD40.
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Affiliation(s)
- Felipe Raúl Donís-Hernández
- Department of Molecular Biomedicine, Centro de Investigación y Estudios Avanzados del I.P.N.México D. F., México
| | | | - Leopoldo Santos-Argumedo
- Department of Molecular Biomedicine, Centro de Investigación y Estudios Avanzados del I.P.N.México D. F., México
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27
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Donís-Hernández FR, Parkhouse RME, Santos-Argumedo L. Ontogeny, distribution and function of CD38-expressing B lymphocytes in mice. Eur J Immunol 2001. [DOI: 10.1002/1521-4141(200104)31:4<1261::aid-immu1261>3.0.co;2-h] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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28
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Cancro MP, Sah AP, Levy SL, Allman DM, Constantinescu D, Schmidt MR, Woodland RT. B cell production and turnover in CBA/Ca, CBA/N and CBA/N-bcl-2 transgenic mice: xid-mediated failure among pre B cells is unaltered by bcl-2 overexpression. Curr Top Microbiol Immunol 2001; 252:31-8. [PMID: 11125490 DOI: 10.1007/978-3-642-57284-5_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The CBA/N strain carries xid, a murine btk missense mutation that reduces peripheral B cell numbers. Using in vivo BrdU labeling and cytofluorimetry, we have compared the magnitude, production rates, and turnover rates of each B lineage subset in the marrow and periphery of CBA/Ca and CBA/N mice. Our results show the pro-B compartment is largely unaffected by xid. In contrast, the pre-B cell pool is markedly reduced, reflecting a diminished production rate and unaltered turnover time. Despite diminished pre-B cell formation, the size of the immature B cell pool is relatively normal in CBA/N mice, due to increased proportional survival of pre-B cells. In addition, we have assessed the marrow and peripheral B cell subsets of CBA/N mice transgenic for bcl-2. These results indicate that while the bcl-2 transgene promotes lengthened survival in most B cell subsets, the pro/pre-B cell losses mediated by xid are not abrogated by bcl-2 overexpression. Taken together, these findings suggest that the initial [not readable: see text] from the pro- to pre-B cell pools, and that anomalies in subsequent compartments likely reflects the action of homeostatic mechanisms compensating for compromised pre-B cell production.
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Affiliation(s)
- M P Cancro
- Univ. of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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29
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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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30
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Santos-Lima EC, Vasconcellos R, Reina-San-Martín B, Fesel C, Cordeiro-Da-Silva A, Berneman A, Cosson A, Coutinho A, Minoprio P. Significant association between the skewed natural antibody repertoire of Xid mice and resistance to Trypanosoma cruzi infection. Eur J Immunol 2001; 31:634-45. [PMID: 11180129 DOI: 10.1002/1521-4141(200102)31:2<634::aid-immu634>3.0.co;2-h] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The Xid mutation predominantly affects the development of B cells and consequently the levels and composition of natural antibodies in sera. In contrast to the congenic and susceptible BALB/c strain, immunodeficient BALB.Xid mice display a resistant phenotype both to acute Trypanosoma cruzi infection and to the development of severe cardiopathy. Because natural antibodies are known to be basically self-antigen driven, IgM and IgG natural antibody repertoires (NAR) were compared before and during infection in these two strains. The analysis revealed fundamental alterations of IgM and IgG NAR in pre- and post-infected Xid mice. In particular, relatively increased natural (pre-existing) autoreactive IgG, dominated by the unique recognition of a single band in autologous heart extracts, was typical for uninfected Xid mice. This natural autoreactive IgG directed to heart antigens disappeared early after infection not only in Xid, but also in individual BALB/c mice that survived the acute infection. Conversely, the subgroup of BALB/c mice that died early after infection presented the most pronounced instances of the rapid, relative increase of IgM reactivities to self and non-self proteins. These results suggest that self-reactive NAR may play a role in an immunoregulatory mechanism relevant for the determination of susceptibility/resistance to infections. This may act either by influencing specific responses, or by modulating the self-aggressive components responsible for pathology.
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Vorechovský I, Luo L, Hertz JM, Frøland SS, Klemola T, Fiorini M, Quinti I, Paganelli R, Ozsahin H, Hammarström L, Webster AD, Smith CI. Mutation pattern in the Bruton's tyrosine kinase gene in 26 unrelated patients with X-linked agammaglobulinemia. Hum Mutat 2000; 9:418-25. [PMID: 9143921 DOI: 10.1002/(sici)1098-1004(1997)9:5<418::aid-humu7>3.0.co;2-#] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Mutation pattern was characterized in the Bruton's tyrosine kinase gene (BTK) in 26 patients with X-linked agammaglobulinemia, the first described immunoglobulin deficiency, and was related to BTK expression. A total of 24 different mutations were identified. Most BTK mutations were found to result in premature termination of the translation product. Mutations were detected in most BTK exons with a predominance of frameshift and nonsense mutations in the 5' end of the gene and missense mutations in its 3' part, corresponding to the catalytic domain of the enzyme. Nonsense and frameshift mutations were associated with diminished levels of BTK mRNA expression, except for a frameshift mutation in exon 17 and two nonsense mutations in exon 2, indicating that these cases are not confined to penultimate exons. One amino acid substitution (R28H) was found in the pleckstrin homology domain's residue, which is mutated in mice bearing the X-linked immunodeficiency phenotype; another substitution (R307G) was identified in the src homology domain 2. All remaining amino acid substitutions were found in the catalytic domain of Btk.
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Affiliation(s)
- I Vorechovský
- Karolinska Institute, Department of Biosciences, NOVUM, Huddinge, Sweden
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32
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Bajpai UD, Zhang K, Teutsch M, Sen R, Wortis HH. Bruton's tyrosine kinase links the B cell receptor to nuclear factor kappaB activation. J Exp Med 2000; 191:1735-44. [PMID: 10811866 PMCID: PMC2193152 DOI: 10.1084/jem.191.10.1735] [Citation(s) in RCA: 168] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The recognition of antigen by membrane immunoglobulin M (mIgM) results in a complex series of signaling events in the cytoplasm leading to gene activation. Bruton's tyrosine kinase (BTK), a member of the Tec family of tyrosine kinases, is essential for the full repertoire of IgM signals to be transduced. We examined the ability of BTK to regulate the nuclear factor (NF)-kappaB/Rel family of transcription factors, as the activation of these factors is required for a B cell response to mIgM. We found greatly diminished IgM- but not CD40-mediated NF-kappaB/Rel nuclear translocation and DNA binding in B cells from X-linked immunodeficient (xid) mice that harbor an R28C mutation in btk, a mutation that produces a functionally inactive kinase. The defect was due, in part, to a failure to fully degrade the inhibitory protein of NF-kappaB, IkappaBalpha. Using a BTK-deficient variant of DT40 chicken B cells, we found that expression of wild-type or gain-of-function mutant BTK, but not the R28C mutant, reconstituted NF-kappaB activity. Thus, BTK is essential for activation of NF-kappaB via the B cell receptor.
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Affiliation(s)
- Urmila D. Bajpai
- Department of Pathology and Program in Immunology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts 02111
| | - Keming Zhang
- Department of Pathology and Program in Immunology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts 02111
| | - Mark Teutsch
- Department of Pathology and Program in Immunology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts 02111
| | - Ranjan Sen
- Rosenstiel Research Center and Department of Biology, Brandeis University, Waltham, Massachusetts 02254
| | - Henry H. Wortis
- Department of Pathology and Program in Immunology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts 02111
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33
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Rawlings DJ. Bruton's tyrosine kinase controls a sustained calcium signal essential for B lineage development and function. Clin Immunol 1999; 91:243-53. [PMID: 10370369 DOI: 10.1006/clim.1999.4732] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Genetic data support a role for Btk during the B lineage development transitions regulated by signaling through both the pre-B and the B cell antigen receptors. Dysregulated signaling at each of these transitions can result in failure of these cell populations to proliferate and subsequent cell death. Btk-dependent IP3 production is crucial for maintaining the sustained calcium signal in response to BCR engagement and is likely to regulate a subset of transcriptional events essential for B lineage growth or survival. Identification of these Btk-dependent signals will be important in understanding B cell activation, differentiation, and cell death. This information may lead to therapies specifically targeting these events in B cell autoimmunity or malignancy and provide a fuller understanding of the appropriate target populations and potential negative consequences of Btk gene therapy in XLA. Identification of Btk/Tec family kinases in an increasing number of vertebrate and invertebrate cell lineages suggests that the link between Btk and the PLC gamma/IP3/calcium signaling pathways may be broadly conserved.
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Affiliation(s)
- D J Rawlings
- Department of Pediatrics, Jonsson Comprehensive Cancer Center, University of California, Los Angeles 90095-1752, USA
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34
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Yasue T, Baba M, Mori S, Mizoguchi C, Uehara S, Takatsu K. IgG1 production by sIgD+ splenic B cells and peritoneal B-1 cells in response to IL-5 and CD38 ligation. Int Immunol 1999; 11:915-23. [PMID: 10360965 DOI: 10.1093/intimm/11.6.915] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
CD38 ligation on mouse B cells by CS/2, an anti-mouse CD38 mAb, induces proliferation, IL-5 receptor alpha chain expression and tyrosine phosphorylation of Bruton's tyrosine kinase. Furthermore, stimulation of splenic B cells with IL-5 together with CS/2 induces Blimp-1 expression and differentiation into Ig-producing cells. Here we examined the role of IL-5 in IgG1 and IgA production by B cells isolated from the spleen and peritoneal cavity. CD38 recognized by CS/2 was expressed in the follicular mantle B cells surrounding the germinal center, sIgD+ splenic B cells and peritoneal B cells. IL-5 induced IgG1 production in splenic sIgD+ B cells stimulated with CS/2, while it was ineffective to induce IgA production. Among the various cytokines tested, only IL-5 had a synergistic effect on IgG1 production with CS/2. IL-5 could induce the generation of S micro-Sgamma1 reciprocal recombination DNA products in CS/2-stimulated B cells. IL-4 was ineffective to induce either micro-gamma1 switch recombination or IgG1 secretion with CS/2, demonstrating that IL-5 promotes both micro-gamma1 switch recombination and IgG1 secretion in an IL-4-independent manner. The peritoneal B-2 cells exhibited both IgG1 and IgA production in response to IL-5 plus CS/2, while B-1 cells produced IgG1. These results imply that the pattern of differentiation to Ig-producing cells seen with peritoneal B cells is not identical to the pattern seen with splenic B cells and that peritoneal B-2 cells contain precursors of IgA-producing cells responding to IL-5 plus CS/2.
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MESH Headings
- ADP-ribosyl Cyclase
- ADP-ribosyl Cyclase 1
- Animals
- Antibodies, Monoclonal/pharmacology
- Antigens, CD
- Antigens, Differentiation/immunology
- Antigens, Differentiation/metabolism
- B-Lymphocyte Subsets/immunology
- B-Lymphocyte Subsets/metabolism
- Cells, Cultured
- Gene Rearrangement, B-Lymphocyte, Heavy Chain
- Immunoglobulin A/biosynthesis
- Immunoglobulin G/biosynthesis
- Immunoglobulin Switch Region
- Immunoglobulin gamma-Chains/biosynthesis
- Immunoglobulin gamma-Chains/genetics
- Immunoglobulin mu-Chains/biosynthesis
- Immunoglobulin mu-Chains/genetics
- Interleukin-5/immunology
- Interleukin-5/metabolism
- Interleukin-5/physiology
- Membrane Glycoproteins
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- NAD+ Nucleosidase/immunology
- NAD+ Nucleosidase/metabolism
- Peritoneal Cavity/cytology
- Receptors, Antigen, B-Cell/biosynthesis
- Spleen/cytology
- Spleen/immunology
- Spleen/metabolism
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Affiliation(s)
- T Yasue
- Departments of Immunology and Pathology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
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35
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Buhl AM, Cambier JC. Phosphorylation of CD19 Y484 and Y515, and Linked Activation of Phosphatidylinositol 3-Kinase, Are Required for B Cell Antigen Receptor-Mediated Activation of Bruton’s Tyrosine Kinase. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.162.8.4438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Bruton’s tyrosine kinase (Btk) plays a critical role in B cell Ag receptor (BCR) signaling, as indicated by the X-linked immunodeficiency and X-linked agammaglobulinemia phenotypes of mice and men that express mutant forms of the kinase. Although Btk activity can be regulated by Src-family and Syk tyrosine kinases, and perhaps by phosphatidylinositol 3,4,5-trisphosphate, BCR-coupled signaling pathways leading to Btk activation are poorly understood. In view of previous findings that CD19 is involved in BCR-mediated phosphatidylinositol 3-kinase (PI3-K) activation, we assessed its role in Btk activation. Using a CD19 reconstituted myeloma model and CD19 gene-ablated animals we found that BCR-mediated Btk activation and phosphorylation are dependent on the expression of CD19, while BCR-mediated activation of Lyn and Syk is not. Wortmannin preincubation inhibited the BCR-mediated activation and phosphorylation of Btk. Btk activation was not rescued in the myeloma by expression of a CD19 mutant in which tyrosine residues previously shown to mediate CD19 interaction with PI3-K, Y484 and Y515, were changed to phenylalanine. Taken together, the data presented indicate that BCR aggregation-driven CD19 phosphorylation functions to promote Btk activation via recruitment and activation of PI3-K. Resultant phosphatidylinositol 3,4,5-trisphosphate probably functions to localize Btk for subsequent phosphorylation and activation by Src and Syk family kinases.
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Affiliation(s)
- Anne Mette Buhl
- *Division of Basic Sciences, Department of Pediatrics, National Jewish Medical and Research Center, and
| | - John C. Cambier
- *Division of Basic Sciences, Department of Pediatrics, National Jewish Medical and Research Center, and
- †Department of Immunology, University of Colorado Health Sciences Center, Denver, CO 80206
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36
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Oliver AM, Grimaldi JC, Howard MC, Kearney JF. Independently ligating CD38 and Fc gammaRIIB relays a dominant negative signal to B cells. Hybridoma (Larchmt) 1999; 18:113-9. [PMID: 10380010 DOI: 10.1089/hyb.1999.18.113] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CD38 is expressed on a variety of hematopoietic cells and has a unique enzymatic activity that converts nicotinamide adenine dinucleotide (NAD) into cyclic ADP-ribose (cADPR) and then into ADPR. CD38 is expressed at increasingly higher levels on B cells at each stage of B cell differentiation, and is then down-regulated on germinal center B cells and mature plasma cells. Crosslinking of CD38 on the surface of mature, resting B cells induces B-cell proliferation, which is enhanced by co-signals such as IL-4 and LPS. CD38-induced proliferation is abrogated by Fc gammaRIIB ligation and this inhibition can be effected by the addition of anti-Fc gammaRII Ab midway through a 48 h in vitro culture indicating that it delivers a potent negative signal to CD38 activated B cells. The suppressive signal was shown to occur through the Fc gammaRIIB because CD38-induced B-cell activation was not inhibited by the ligation of Fc gammaRIIB in Fc gammaRII-deficient B cells. These results indicate that Fc gammaRIIB can act as a regulatory molecule that modulates CD38 signals in vivo.
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Affiliation(s)
- A M Oliver
- Department of Microbiology, University of Alabama at Birmingham, 35294-3300, USA
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37
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Nisitani S, Kato RM, Rawlings DJ, Witte ON, Wahl MI. In situ detection of activated Bruton's tyrosine kinase in the Ig signaling complex by phosphopeptide-specific monoclonal antibodies. Proc Natl Acad Sci U S A 1999; 96:2221-6. [PMID: 10051622 PMCID: PMC26764 DOI: 10.1073/pnas.96.5.2221] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/1998] [Indexed: 11/18/2022] Open
Abstract
Bruton's tyrosine kinase (Btk) is a critical transducer of signals originating from the B cell antigen receptor (BCR). Dosage, sequential phosphorylation, and protein interactions are interdependent mechanisms influencing Btk function. Phosphopeptide-specific mAbs recognizing two distinct phosphotyrosine modifications were used to quantify Btk activation by immunofluorescent techniques during B cell stimulation. In a population of cultured B cells stimulated by BCR crosslinking and analyzed by flow cytometry, transient phosphorylation of the regulatory Btk tyrosine residues (551Y and 223Y) was detected. The kinetics of phosphorylation of the residues were temporally distinct. Tyrosine 551, a transactivating substrate site for Src-family kinases, was maximally phosphorylated within approximately 30 seconds of stimulation as monitored by flow cytometry. Tyrosine 223, an autophosphorylation site within the SH3 domain, was maximally phosphorylated at approximately 5 minutes. Btk returned to a low tyrosine phosphorylation level within 30 minutes, despite persistent elevation of global tyrosine phosphorylation. Colocalization of activated Btk molecules with the crosslinked BCR signaling complex was observed to coincide with the period of maximal Btk tyrosine phosphorylation when stimulated B cells were analyzed with confocal microscopy. The results of these in situ temporal and spatial analyses imply that Btk signaling occurs in the region of the Ig receptor signaling complex, suggesting a similar location for downstream targets of its activity.
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Affiliation(s)
- S Nisitani
- Department of Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095, USA
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38
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Klaus GG, Holman M, Johnson-Léger C, Christenson JR, Kehry MR. Interaction of B cells with activated T cells reduces the threshold for CD40-mediated B cell activation. Int Immunol 1999; 11:71-9. [PMID: 10050675 DOI: 10.1093/intimm/11.1.71] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
CD154-CD40 interactions are of central importance for the induction of antibody responses to T-dependent antigens. Since most anti-CD40 mAb are only weak B cell mitogens, it is believed that under physiological conditions, signals through CD40 synergize with those from other receptors on B cells to induce B cell activation. We show here that the interaction of either normal B cells, or those from CBA/N (xid) mice, with CD3-activated primary T cells in whole spleen cell cultures markedly reduces the threshold for B cell activation via CD40. Hence, these pre-activated cells undergo vigorous proliferation when stimulated with either optimal or suboptimal concentrations of weakly mitogenic anti-CD40 mAb, or with soluble CD40 ligand. Blocking experiments indicate that the establishment of this priming effect requires stimulation via CD40 itself, plus T cell-derived IL-2. In support of this concept, only CD3/CD28-pre-activated, but not CD3-pre-activated T cells induce this effect, unless the co-cultures of B cells with the latter T cells are supplemented with IL-2. Although B cells activated in this fashion do express higher levels of CD40 than naive cells, we believe that this is insufficient to explain the observed dramatic effects on their proliferative capacity. Rather we propose that T cell-dependent B cell activation induces fundamental changes in the signalling machinery invoked by ligation of CD40. It is likely that this amplification loop could play an important role during the initiation of antibody responses to T-dependent antigens, when activated CD4 T cells only express low levels of CD154.
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Affiliation(s)
- G G Klaus
- Division of Cellular Immunology, National Institute for Medical Research, London, UK
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39
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Nonoyama S, Tsukada S, Yamadori T, Miyawaki T, Jin YZ, Watanabe C, Morio T, Yata JI, Ochs HD. Functional Analysis of Peripheral Blood B Cells in Patients with X-Linked Agammaglobulinemia. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.8.3925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
X-linked agammaglobulinemia (XLA) is a primary immunodeficiency disease caused by mutations of Bruton tyrosine kinase (Btk); Btk plays an essential role in the development of mature B cells. However, small numbers of B cells (“leaky B cells”) are present in the peripheral blood of most XLA patients. In this study, we analyzed the function of these leaky B cells obtained from XLA patients. Enough numbers of B cells were available for analysis from five of nine XLA patients originally screened. Sequence analysis revealed missense mutations of Btk in four of the five XLA patients. No mutation was found in the coding region of Btk in one patient. Western blotting and/or flow cytometric analysis failed to detect Btk protein in all five patients. B cells isolated from peripheral blood of these XLA patients were CD5−, CD20+, CD19+, and CD21−. If stimulated with anti-CD40 and IL-4, XLA B cells proliferated normally and produced significant amounts of IgE. Anti-CD40 stimulation of XLA B cells resulted in normal expression of CD23. In addition, three of the five XLA patients studied were immunized with bacteriophage φX174 and produced low but detectable levels of antiphage-specific Ab. Similarly, X-linked immunodeficiency mice, which carry a missense mutation in Btk, produced substantial amounts of antiphage Ab. These results indicate that CD40 signaling is intact in B cells lacking demonstrable Btk, and that leaky B cells in XLA patients can proliferate, undergo isotype switching, and differentiate into specific Ab-producing cells.
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Affiliation(s)
- Shigeaki Nonoyama
- *Department of Pediatrics, University of Washington, Seattle, WA 98195
- §Department of Pediatrics, Tokyo Medical and Dental University, Tokyo, Japan
| | - Satoshi Tsukada
- †Department of Medicine III, Osaka University Medical School, Osaka, Japan
| | - Tomoki Yamadori
- †Department of Medicine III, Osaka University Medical School, Osaka, Japan
| | - Toshio Miyawaki
- ‡Department of Pediatrics, Toyama Medical and Pharmaceutical University, Toyama, Japan; and
| | - Yin Zhu Jin
- §Department of Pediatrics, Tokyo Medical and Dental University, Tokyo, Japan
| | - Chiaki Watanabe
- *Department of Pediatrics, University of Washington, Seattle, WA 98195
| | - Tomohiro Morio
- §Department of Pediatrics, Tokyo Medical and Dental University, Tokyo, Japan
| | - Jun-Ichi Yata
- §Department of Pediatrics, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hans D. Ochs
- *Department of Pediatrics, University of Washington, Seattle, WA 98195
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40
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Itoh M, Ishihara K, Hiroi T, Ok Lee B, Maeda H, Iijima H, Yanagita M, Kiyono H, Hirano T. Deletion of Bone Marrow Stromal Cell Antigen-1 (CD157) Gene Impaired Systemic Thymus Independent-2 Antigen-Induced IgG3 and Mucosal TD Antigen-Elicited IgA Responses. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.8.3974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Bone marrow stromal cell Ag-1 (BST-1; CD157)-deficient mice were generated to examine the immunologic roles of the molecule in vivo. In BST-1−/− mice, the development of peritoneal B-1 cells was delayed, and CD38low/− B-lineage cells were increased in the bone marrow and spleen. Partial impairment of thymus-independent (TI-2) and thymus-dependent (TD) Ag-specific immune responses was noted in the systemic and mucosal compartments of BST-1−/− mice, respectively. Although serum Ig levels as well as TD and TI-1 Ag-specific systemic immune responses were normal, the TI-2 Ag-induced IgG3 response was selectively impaired. Oral immunization of BST-1−/− mice with cholera toxin, a potent TD Ag for the induction of IgA response, resulted in the poor production of Ag-specific Abs at the intestinal mucosa accompanied by the reduced number of Ag-specific IgA-producing cells in the lamina propria. These results indicate that BST-1 has roles in B cell development and Ab production in vivo.
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Affiliation(s)
- Motoyuki Itoh
- *Division of Molecular Oncology, Biomedical Research Center, Osaka University Medical School, Osaka, Japan; and
| | - Katsuhiko Ishihara
- *Division of Molecular Oncology, Biomedical Research Center, Osaka University Medical School, Osaka, Japan; and
| | - Takachika Hiroi
- †Department of Mucosal Immunology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Byung Ok Lee
- *Division of Molecular Oncology, Biomedical Research Center, Osaka University Medical School, Osaka, Japan; and
| | - Hisoka Maeda
- *Division of Molecular Oncology, Biomedical Research Center, Osaka University Medical School, Osaka, Japan; and
| | - Hideki Iijima
- †Department of Mucosal Immunology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Manabu Yanagita
- †Department of Mucosal Immunology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Hiroshi Kiyono
- †Department of Mucosal Immunology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Toshio Hirano
- *Division of Molecular Oncology, Biomedical Research Center, Osaka University Medical School, Osaka, Japan; and
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41
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Mallone R, Ferrua S, Morra M, Zocchi E, Mehta K, Notarangelo LD, Malavasi F. Characterization of a CD38-like 78-kilodalton soluble protein released from B cell lines derived from patients with X-linked agammaglobulinemia. J Clin Invest 1998; 101:2821-30. [PMID: 9637716 PMCID: PMC508873 DOI: 10.1172/jci1068] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Studies on murine B lymphocytes showed that Bruton's tyrosine kinase mediates signal transduction induced via CD38, a nonlineage-restricted 45-kD ectoenzyme. This signaling is defective in B cells from X-linked immunodeficient mice affected with the analogue of human X-linked agammaglobulinemia (XLA). We performed a structural and functional analysis of CD38 in XLA and other immunodeficiencies, using EBV-immortalized B cells derived from such patients. Membrane CD38 was not significantly different from controls in structure, epitope density, enzymatic activity, and internalization upon binding of agonistic mAbs. Meanwhile, an increased release of soluble CD38 from XLA cells was observed: immunoprecipitation from XLA culture media yielded a protein of approximately 78 kD (p78), reacting also in Western blot and displaying both enzymatic activities and a peptide map similar to membrane CD38. Soluble forms and homotypic aggregations of CD38 were documented in different cell models and by crystallographic analysis of the Aplysia ADP-ribosyl cyclase, the ancestor of human CD38. p78 might represent the product of an altered turn-over of membrane CD38, a starting point for studying its association with Bruton's tyrosine kinase and its role in XLA and other B cell immunodeficiencies.
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Affiliation(s)
- R Mallone
- Laboratory of Cell Biology, Department of Genetics, Biology, and Biochemistry, University of Torino, 10126 Torino, Italy
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42
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Hata D, Kawakami Y, Inagaki N, Lantz CS, Kitamura T, Khan WN, Maeda-Yamamoto M, Miura T, Han W, Hartman SE, Yao L, Nagai H, Goldfeld AE, Alt FW, Galli SJ, Witte ON, Kawakami T. Involvement of Bruton's tyrosine kinase in FcepsilonRI-dependent mast cell degranulation and cytokine production. J Exp Med 1998; 187:1235-47. [PMID: 9547335 PMCID: PMC2212237 DOI: 10.1084/jem.187.8.1235] [Citation(s) in RCA: 197] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/1997] [Revised: 01/02/1998] [Indexed: 11/04/2022] Open
Abstract
We investigated the role of Bruton's tyrosine kinase (Btk) in FcepsilonRI-dependent activation of mouse mast cells, using xid and btk null mutant mice. Unlike B cell development, mast cell development is apparently normal in these btk mutant mice. However, mast cells derived from these mice exhibited significant abnormalities in FcepsilonRI-dependent function. xid mice primed with anti-dinitrophenyl monoclonal IgE antibody exhibited mildly diminished early-phase and severely blunted late-phase anaphylactic reactions in response to antigen challenge in vivo. Consistent with this finding, cultured mast cells derived from the bone marrow cells of xid or btk null mice exhibited mild impairments in degranulation, and more profound defects in the production of several cytokines, upon FcepsilonRI cross-linking. Moreover, the transcriptional activities of these cytokine genes were severely reduced in FcepsilonRI-stimulated btk mutant mast cells. The specificity of these effects of btk mutations was confirmed by the improvement in the ability of btk mutant mast cells to degranulate and to secrete cytokines after the retroviral transfer of wild-type btk cDNA, but not of vector or kinase-dead btk cDNA. Retroviral transfer of Emt (= Itk/Tsk), Btk's closest relative, also partially improved the ability of btk mutant mast cells to secrete mediators. Taken together, these results demonstrate an important role for Btk in the full expression of FcepsilonRI signal transduction in mast cells.
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Affiliation(s)
- D Hata
- Division of Allergy, La Jolla Institute for Allergy and Immunology, San Diego, California 92121, USA
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43
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Abstract
Interleukin-5 (IL-5) stimulates proliferation and differentiation of B cells and eosinophils. IL-5 receptor (IL-5R) comprises alpha and (beta)c chains. IL-5 specifically binds to IL-5Ralpha and induces the recruitment of (beta)c to IL-5Ralpha. JAK2 and JAK1 tyrosine kinases are constitutively associated with hIL-5Ralpha and (beta)c, respectively and activated upon IL-5 stimulation. IL-5 induces tyrosine phosphorylations of cellular proteins including (beta)c and STAT5 and activates Btk. X-linked immunodeficient mice have B-cell-specific defects due to missense mutation of the btk gene. The cytoplasmic proline-rich regions of both IL-5Ralpha and (beta)c are essential for the IL-5 signalling. IL-5 appears to play a critical role in hypereosinophilic syndromes and atopic diseases. The treatment of animals with anti-IL-5 mAb can decrease the enhanced bronchial responsiveness induced by allergen sensitization. Clinical studies provide a strong impetus for investigating the means of modulating IL-5 effects.
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Affiliation(s)
- K Takatsu
- Department of Immunology, Institute of Medical Science, University of Tokyo, Japan
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Lund FE, Cockayne DA, Randall TD, Solvason N, Schuber F, Howard MC. CD38: a new paradigm in lymphocyte activation and signal transduction. Immunol Rev 1998; 161:79-93. [PMID: 9553766 DOI: 10.1111/j.1600-065x.1998.tb01573.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
CD38 is a type II transmembrane glycoprotein that is extensively expressed on cells of hematopoietic and non-hematopoietic lineage. Although the intracellular domain of CD38 is not homologous to any known proteins, the extracellular domain of CD38 is structurally related to enzymes in the ADP-ribosyl cyclase family. The structural homology between CD38 and the cyclase family members extends to functional homology, as the extracellular domain of CD38 can mediate the catalysis of beta-NAD+ into nicotinamide, ADP-ribose (ADPR) and, to a lesser extent, into cyclic ADPR-ribose (cADPR). Extensive investigation in other systems has shown that cADPR is an important regulator of intracellular Ca2+ release. Since engagement of CD38 on hematopoietic cells with anti-CD38 Abs has been shown to have potent effects on a number of in vitro cellular responses, we have speculated that cADPR might control CD38-mediated signal transduction. However, it has been difficult to understand how a mediator which is typically an intracellular signaling molecule could potentiate its effects from an extracellular location, thus posing a dilemma which pertains to all ecto-enzymes and the mechanisms by which they regulate signal transduction and cellular processes. This review describes the biologic properties of murine CD38, its role in humoral immunity, and its signal transduction properties in B lymphocytes. We suggest that signaling through CD38 represents a new paradigm in lymphocyte signal transduction and is predicated upon extracellular, rather than intracellular, crosstalk.
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Affiliation(s)
- F E Lund
- Trudeau Institute, Saranac Lake, New York 12983, USA.
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Dullforce P, Sutton DC, Heath AW. Enhancement of T cell-independent immune responses in vivo by CD40 antibodies. Nat Med 1998; 4:88-91. [PMID: 9427612 DOI: 10.1038/nm0198-088] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this report we describe a potentially powerful method for vaccinating infants against encapsulated bacterial pathogens such as Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis. High levels of antibody directed against the polysaccharides of the bacterial capsule are normally protective. Unfortunately, the capsular polysaccharides are T cell-independent antigens (TI); lacking T-cell help, they induce only weak, predominantly IgM antibody responses, with infants responding especially poorly. T-cell help, given to B cells during responses to protein antigens, causes stronger antibody responses and isotype switching to the IgG isotypes. T-cell help is mainly mediated through ligation of the B-cell surface antigen, CD40, by its cognate T-cell ligand, CD154. Here we show that administering anti-CD40 monoclonal antibody to mice, along with pneumococcal polysaccharide, provides a substitute for T-cell help and results in the generation of strong, isotype-switched antibody responses, which are protective. The work points the way toward a possible effective and inexpensive means of protecting susceptible groups against important bacterial pathogens.
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Affiliation(s)
- P Dullforce
- Division of Molecular and Genetic Medicine and Sheffield Institute for Vaccine Studies, University of Sheffield Medical School, UK
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Satterthwaite AB, Cheroutre H, Khan WN, Sideras P, Witte ON. Btk dosage determines sensitivity to B cell antigen receptor cross-linking. Proc Natl Acad Sci U S A 1997; 94:13152-7. [PMID: 9371815 PMCID: PMC24278 DOI: 10.1073/pnas.94.24.13152] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Mutations in Btk result in the B cell immunodeficiencies X-linked agammaglobulinemia (XLA) in humans and X-linked immunodeficiency (xid) in mice. Btk is a critical component of signaling pathways regulating B cell development and function. We used a genetic approach to determine whether Btk is also limiting for these processes. One allele of a murine Btk transgene expressed a dosage of Btk (25% of endogenous levels in splenic B cells) sufficient to restore normal numbers of phenotypically mature conventional B cells in xid mice. 2,4,6-trinitrophenyl-Ficoll response, anti-IgM-induced proliferation, B1 cell development, and serum IgM and IgG3 levels remained significantly impaired in these animals. B cells from Btk -/- transgenic mice also responded poorly to anti-IgM, indicating that the xid mutation does not create a dominant negative form of Btk. Response to 2,4,6-trinitrophenyl-Ficoll and B cell receptor cross-linking were increased 3- to 4-fold in xid mice homozygous for the transgene. These results demonstrate that Btk is a limiting component of B cell antigen receptor signaling pathways and suggest that B cell development and response to antigen may require different levels of Btk activity.
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Affiliation(s)
- A B Satterthwaite
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles 90095, USA
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Klaus GG, Holman M, Johnson-Léger C, Elgueta-Karstegl C, Atkins C. A re-evaluation of the effects of X-linked immunodeficiency (xid) mutation on B cell differentiation and function in the mouse. Eur J Immunol 1997; 27:2749-56. [PMID: 9394795 DOI: 10.1002/eji.1830271102] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
CBA/N (xid) mice have a point mutation in Bruton's tyrosine kinase (btk), which results in their failure to respond to T-independent type 2 (TI-2) antigens, and to several B cell mitogens [most notably anti-immunoglobulin (Ig)] in vitro. They have reduced numbers of peripheral (B2) B cells, which are regarded as being phenotypically and functionally immature. We show here that adult CBA/N mice in fact have two distinct B cell populations: some 60% of the cells are CD23+ HSAlo sIgDhi and hence resemble recirculating, follicular (RF) B cells from normal mice, except that they are sIgMhi. The remaining 40% of xid B cells are CD23- HSAhi sIgD-/lo and resemble immature transitional (TR) B cells. TR B cells from xid mice do not synthesize DNA when cultured with lipopolysaccharide (LPS), whereas those from normal mice do so. Only the RF cells from either xid or normal mice proliferate in response to ligation of CD40. In neonatal normal mice the emergence of mitogen responsiveness followed the chronological sequence LPS-->anti-CD40-->anti-Ig approximately anti-CD38. The same developmental sequence was seen with B cells from xid mice (for LPS and anti-CD40), but it occurred at a significantly slower tempo and this correlated with the later appearance of RF-type cells. TR xid B cells express very low levels of bcl-2 and we conclude that these cells resemble very immature (bone marrow) B cells, rather than normal transitional cells. We, therefore, propose that the xid mutation imposes a multistage brake on B cell differentiation in the mouse. The available data suggest that btk is required for the positive selection of B cells throughout their differentiation in the periphery. This in turn implies that low level signaling via surface Ig is needed throughout this process in order for peripheral B cells to become functionally mature.
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Affiliation(s)
- G G Klaus
- Division of Cellular Immunology, National Institute for Medical Research, London, GB
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Wahl MI, Fluckiger AC, Kato RM, Park H, Witte ON, Rawlings DJ. Phosphorylation of two regulatory tyrosine residues in the activation of Bruton's tyrosine kinase via alternative receptors. Proc Natl Acad Sci U S A 1997; 94:11526-33. [PMID: 9326643 PMCID: PMC23526 DOI: 10.1073/pnas.94.21.11526] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Mutation of Bruton's tyrosine kinase (Btk) impairs B cell maturation and function and results in a clinical phenotype of X-linked agammaglobulinemia. Activation of Btk correlates with an increase in the phosphorylation of two regulatory Btk tyrosine residues. Y551 (site 1) within the Src homology type 1 (SH1) domain is transphosphorylated by the Src family tyrosine kinases. Y223 (site 2) is an autophosphorylation site within the Btk SH3 domain. Polyclonal, phosphopeptide-specific antibodies were developed to evaluate the phosphorylation of Btk sites 1 and 2. Crosslinking of the B cell antigen receptor (BCR) or the mast cell Fcepsilon receptor, or interleukin 5 receptor stimulation each induced rapid phosphorylation at Btk sites 1 and 2 in a tightly coupled manner. Btk molecules were singly and doubly tyrosine-phosphorylated. Phosphorylated Btk comprised only a small fraction (</=5%) of the total pool of Btk molecules in the BCR-activated B cells. Increased dosage of Lyn in B cells augmented BCR-induced phosphorylation at both sites. Kinetic analysis supports a sequential activation mechanism in which individual Btk molecules undergo serial transphosphorylation (site 1) then autophosphorylation (site 2), followed by successive dephosphorylation of site 1 then site 2. The phosphorylation of conserved tyrosine residues within structurally related Tec family kinases is likely to regulate their activation.
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Affiliation(s)
- M I Wahl
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles, CA 90095-1662, USA
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Yasue T, Nishizumi H, Aizawa S, Yamamoto T, Miyake K, Mizoguchi C, Uehara S, Kikuchi Y, Takatsu K. A critical role of Lyn and Fyn for B cell responses to CD38 ligation and interleukin 5. Proc Natl Acad Sci U S A 1997; 94:10307-12. [PMID: 9294206 PMCID: PMC23358 DOI: 10.1073/pnas.94.19.10307] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
CD38 ligation on mouse B cells by CS/2, an anti-mouse CD38 mAb, induced proliferation, interleukin 5 (IL-5) receptor alpha chain expression, and tyrosine phosphorylation of Bruton tyrosine kinase (Btk) from wild-type, but not from X chromosome-linked, immunodeficient mice. B cells from fyn-deficient (Fyn-/-) and lyn-deficient (Lyn-/-) mice showed an impaired response to mAb CS/2 for proliferation and IL-5 receptor alpha chain expression, and B cells from fyn/lyn double-deficient (Fyn/Lyn-/-) mice did not respond at all to mAb CS/2. The Btk activation by CD38 ligation was observed in B cells from Fyn-/- mice, and it was severely impaired in B cells from Lyn-/- and Fyn/Lyn-/- mice. CD38 expression on B cells from three mutant strains was comparable to that on control B cells. We infer from these results that both Fyn and Lyn are required and that their signals are synergistic for B cell triggering after CD38 ligation. Lyn is upstream of Btk activation in the CD38 signaling. Stimulation of B cells with IL-5 together with CD38 ligation induces not only IgM but also IgG1 secretion. Analysis of the synergistic effects of IL-5 and CD38 ligation on IgG1 secretion revealed the impaired IgG1 secretion of B cells from Lyn-/- and Fyn/Lyn-/- mice. These data imply that Lyn is involved in B cell triggering by CD38 ligation plus IL-5 for isotype switching.
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Affiliation(s)
- T Yasue
- Department of Immunology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108 Japan
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Shubinsky G, Schlesinger M. The CD38 lymphocyte differentiation marker: new insight into its ectoenzymatic activity and its role as a signal transducer. Immunity 1997; 7:315-24. [PMID: 9324352 DOI: 10.1016/s1074-7613(00)80353-2] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- G Shubinsky
- The Paul Ehrlich Center for the Study of Normal and Leukemic WBC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
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