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Hu YZ, Li Q, Wang PF, Li XP, Hu ZL. Multiple functions and regulatory network of miR-150 in B lymphocyte-related diseases. Front Oncol 2023; 13:1140813. [PMID: 37182123 PMCID: PMC10172652 DOI: 10.3389/fonc.2023.1140813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 04/06/2023] [Indexed: 05/16/2023] Open
Abstract
MicroRNAs (miRNAs) play vital roles in the post-transcriptional regulation of gene expression. Previous studies have shown that miR-150 is a crucial regulator of B cell proliferation, differentiation, metabolism, and apoptosis. miR-150 regulates the immune homeostasis during the development of obesity and is aberrantly expressed in multiple B-cell-related malignant tumors. Additionally, the altered expression of MIR-150 is a diagnostic biomarker of various autoimmune diseases. Furthermore, exosome-derived miR-150 is considered as prognostic tool in B cell lymphoma, autoimmune diseases and immune-mediated disorders, suggesting miR-150 plays a vital role in disease onset and progression. In this review, we summarized the miR-150-dependent regulation of B cell function in B cell-related immune diseases.
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Affiliation(s)
- Yue-Zi Hu
- Clinical Laboratory, The Second Affiliated Hospital of Hunan University of Chinese Medicine, Changsha, China
| | - Qiao Li
- Department of Anesthesiology, The Second Affiliated Xiangya Hospital, Central South University, Changsha, China
| | - Peng-Fei Wang
- Department of Anesthesiology, The Second Affiliated Xiangya Hospital, Central South University, Changsha, China
| | - Xue-Ping Li
- Department of Orthopaedic Surgery, Stanford University School of Medicine, Stanford, CA, United States
| | - Zhao-Lan Hu
- Department of Anesthesiology, The Second Affiliated Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Zhao-Lan Hu,
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2
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BCR-Induced Ca 2+ Signals Dynamically Tune Survival, Metabolic Reprogramming, and Proliferation of Naive B Cells. Cell Rep 2021; 31:107474. [PMID: 32294437 PMCID: PMC7301411 DOI: 10.1016/j.celrep.2020.03.038] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 02/10/2020] [Accepted: 03/12/2020] [Indexed: 01/06/2023] Open
Abstract
B cell receptor (BCR) engagement induces naive B cells to differentiate and perform critical immune-regulatory functions. Acquisition of functional specificity requires that a cell survive, enter the cell cycle, and proliferate. We establish that quantitatively distinct Ca2+ signals triggered by variations in the extent of BCR engagement dynamically regulate these transitions by controlling nuclear factor κB (NF-κB), NFAT, and mTORC1 activity. Weak BCR engagement induces apoptosis by failing to activate NF-κB-driven anti-apoptotic gene expression. Stronger signals that trigger more robust Ca2+ signals promote NF-κB-dependent survival and NFAT-, mTORC1-, and c-Myc-dependent cell-cycle entry and proliferation. Finally, we establish that CD40 or TLR9 costimulation circumvents these Ca2+-regulated checkpoints of B cell activation and proliferation. As altered BCR signaling is linked to autoimmunity and B cell malignancies, these results have important implications for understanding the pathogenesis of aberrant B cell activation and differentiation and therapeutic approaches to target these responses. Berry et al. establish that variations in the strength of BCR engagement are encoded as quantitatively distinct calcium signals that tune B cell fates by dynamically regulating NF-κB, NFAT, and mTORC1 activity. Targeting calcium signaling may thereby serve as an effective treatment strategy for regulating normal and pathological B cell activation.
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3
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Salazar-Fontana LI, Desai DD, Khan TA, Pillutla RC, Prior S, Ramakrishnan R, Schneider J, Joseph A. Approaches to Mitigate the Unwanted Immunogenicity of Therapeutic Proteins during Drug Development. AAPS JOURNAL 2017; 19:377-385. [DOI: 10.1208/s12248-016-0030-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 12/15/2016] [Indexed: 12/17/2022]
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4
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Colombo M, Cutrona G, Reverberi D, Bruno S, Ghiotto F, Tenca C, Stamatopoulos K, Hadzidimitriou A, Ceccarelli J, Salvi S, Boccardo S, Calevo MG, De Santanna A, Truini M, Fais F, Ferrarini M. Expression of immunoglobulin receptors with distinctive features indicating antigen selection by marginal zone B cells from human spleen. Mol Med 2013; 19:294-302. [PMID: 23877718 PMCID: PMC4344459 DOI: 10.2119/molmed.2013.00069] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 07/11/2013] [Indexed: 01/21/2023] Open
Abstract
Marginal zone (MZ) B cells, identified as surface (s)IgM(high)sIgD(low)CD23(low/-)CD21(+)CD38(-) B cells, were purified from human spleens, and the features of their V(D)J gene rearrangements were investigated and compared with those of germinal center (GC), follicular mantle (FM) and switched memory (SM) B cells. Most MZ B cells were CD27(+) and exhibited somatic hypermutations (SHM), although to a lower extent than SM B cells. Moreover, among MZ B-cell rearrangements, recurrent sequences were observed, some of which displayed intraclonal diversification. The same diversifying sequences were detected in very low numbers in GC and FM B cells and only when a highly sensitive, gene-specific polymerase chain reaction was used. This result indicates that MZ B cells could expand and diversify in situ and also suggested the presence of a number of activation-induced cytidine deaminase (AID)-expressing B cells in the MZ. The notion of antigen-driven expansion/selection in situ is further supported by the VH CDR3 features of MZ B cells with highly conserved amino acids at specific positions and by the finding of shared ("stereotyped") sequences in two different spleens. Collectively, the data are consistent with the notion that MZ B cells are a special subset selected by in situ antigenic stimuli.
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Affiliation(s)
- Monica Colombo
- Direzione Scientifica, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Azienda Ospedaliera Universitaria (AOU) San Martino-IST, Genoa, Italy
| | - Giovanna Cutrona
- Division of Molecular Diagnostics, IRCCS AOU San Martino-IST, Genoa, Italy
| | | | - Silvia Bruno
- Department Experimental Medicine, University of Genoa, Genoa, Italy
| | - Fabio Ghiotto
- Department Experimental Medicine, University of Genoa, Genoa, Italy
| | - Claudya Tenca
- Department Experimental Medicine, University of Genoa, Genoa, Italy
| | - Kostas Stamatopoulos
- Institute of Agrobiotechnology, Center for Research and Technology Hellas, Thessaloniki, Greece
- Hematology Department and Hematopoietic Cell Transplantation (HCT) Unit, G. Papanicolau Hospital, Thessaloniki, Greece
| | | | - Jenny Ceccarelli
- Direzione Scientifica, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Azienda Ospedaliera Universitaria (AOU) San Martino-IST, Genoa, Italy
| | - Sandra Salvi
- Division of Pathology, IRCCS AOU San Martino-IST, Genoa, Italy
| | - Simona Boccardo
- Division of Pathology, IRCCS AOU San Martino-IST, Genoa, Italy
| | - Maria Grazia Calevo
- Division of Epidemiology and Statistic, IRCCS Istituto G. Gaslini, Genoa, Italy
| | | | - Mauro Truini
- Division of Pathology, IRCCS AOU San Martino-IST, Genoa, Italy
| | - Franco Fais
- Department Experimental Medicine, University of Genoa, Genoa, Italy
| | - Manlio Ferrarini
- Direzione Scientifica, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Azienda Ospedaliera Universitaria (AOU) San Martino-IST, Genoa, Italy
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5
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Abstract
Apoptosis induced by B-cell receptor (BCR) signaling is critical for antigen-driven selection, a process critical to tolerance and immunity. Here, we examined the roles of microRNAs (miRNAs) in BCR signaling-induced apoptosis using the widely applied WEHI-231 model. Comparison of miRNA levels in BCR-stimulated and -unstimulated cells revealed that 39 miRNAs were differentially expressed upon stimulation of the BCR. Importantly, stimulation in the presence of anti-CD40 antibodies, which rescues cells from BCR-induced apoptosis, prevented most changes in miRNA expression. Ectopic expression of mir-150 and mir-181a1b1, miRNAs that were upregulated upon BCR stimulation, resulted in inhibition of cell growth. Finally, we showed that ectopic expression of mir-150, mir-181a1b1 and mir-17∼92 sensitized cells to anti-IgM stimulation-induced growth inhibition. Together, these results demonstrate that miRNAs are involved in BCR signaling, suggesting that they may have important roles in the regulation of B cell-mediated tolerance and immunity.
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Tuning of CD40–CD154 Interactions in Human B-Lymphocyte Activation: A Broad Array of In Vitro Models for a Complex In Vivo Situation. Arch Immunol Ther Exp (Warsz) 2011; 59:25-40. [DOI: 10.1007/s00005-010-0108-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Accepted: 08/19/2010] [Indexed: 12/13/2022]
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Good-Jacobson KL, Shlomchik MJ. Plasticity and heterogeneity in the generation of memory B cells and long-lived plasma cells: the influence of germinal center interactions and dynamics. THE JOURNAL OF IMMUNOLOGY 2010; 185:3117-25. [PMID: 20814029 DOI: 10.4049/jimmunol.1001155] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the humoral response, short-lived plasmablasts generate an early burst of Ab that probably plays an initial protective role. Simultaneously, another arm of the response is often triggered that leads to delayed effector function but long-term protection. This arm comprises the germinal center response and its products: long-lived memory B (B(mem)) cells and plasma cells (PCs). The factors that control the differentiation of PCs and B(mem) cells, as well as the composition and function of the memory compartment--how it self-renews while generating rapid secondary effector function--are poorly understood. Recent work in mice and humans is beginning to illuminate these issues. We review this progress, with emphasis on events in the germinal center, especially B-T interactions, which influence the development of memory and PC compartments and on B(mem) cell heterogeneity that may underlie flexibility and self-renewal of long-lived humoral immunity.
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Affiliation(s)
- Kim L Good-Jacobson
- Department of Laboratory Medicine, Yale University, New Haven, CT 06519, USA
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8
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Hauser AE, Kerfoot SM, Haberman AM. Cellular choreography in the germinal center: new visions from in vivo imaging. Semin Immunopathol 2010; 32:239-55. [PMID: 20614218 DOI: 10.1007/s00281-010-0214-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 06/22/2010] [Indexed: 11/25/2022]
Abstract
Germinal centers (GC) are large aggregates of proliferating B lymphocytes within follicles of lymphoid tissue that form during adaptive immune responses. GCs are the source of long-lived B cells that form the basis for pathogen-specific lifelong B cell immunity. The complex architecture of these structures includes subdomains that differ significantly in their stromal cell and T lymphocyte subset composition. In part due to their structural complexity and potential to generate some lymphomas, much interest and many theories about GC dynamics have emerged. Here, we review recent research employing in vivo imaging that has begun to untangle some of the mysteries.
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Affiliation(s)
- Anja E Hauser
- Deutsches Rheuma-Forschungszentrum (DRFZ), Berlin 10117, Germany
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9
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Aït-Azzouzene D, Kono DH, Gonzalez-Quintial R, McHeyzer-Williams LJ, Lim M, Wickramarachchi D, Gerdes T, Gavin AL, Skog P, McHeyzer-Williams MG, Nemazee D, Theofilopoulos AN. Deletion of IgG-switched autoreactive B cells and defects in Fas(lpr) lupus mice. THE JOURNAL OF IMMUNOLOGY 2010; 185:1015-27. [PMID: 20554953 DOI: 10.4049/jimmunol.1000698] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
During a T cell-dependent Ab response, B cells undergo Ab class switching and V region hypermutation, with the latter process potentially rendering previously innocuous B cells autoreactive. Class switching and hypermutation are temporally and anatomically linked with both processes dependent on the enzyme, activation-induced deaminase, and occurring principally, but not exclusively, in germinal centers. To understand tolerance regulation at this stage, we generated a new transgenic mouse model expressing a membrane-tethered gamma2a-reactive superantigen (gamma2a-macroself Ag) and assessed the fate of emerging IgG2a-expressing B cells that have, following class switch, acquired self-reactivity of the Ag receptor to the macroself-Ag. In normal mice, self-reactive IgG2a-switched B cells were deleted, leading to the selective absence of IgG2a memory responses. These findings identify a novel negative selection mechanism for deleting mature B cells that acquire reactivity to self-Ag. This process was only partly dependent on the Bcl-2 pathway, but markedly inefficient in MRL-Fas(lpr) lupus mice, suggesting that defective apoptosis of isotype-switched autoreactive B cells is central to Fas mutation-associated systemic autoimmunity.
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Affiliation(s)
- Djemel Aït-Azzouzene
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA
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10
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Kochi Y, Myouzen K, Yamada R, Suzuki A, Kurosaki T, Nakamura Y, Yamamoto K. FCRL3, an Autoimmune Susceptibility Gene, Has Inhibitory Potential on B-Cell Receptor-Mediated Signaling. THE JOURNAL OF IMMUNOLOGY 2009; 183:5502-10. [DOI: 10.4049/jimmunol.0901982] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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11
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Treml LS, Quinn WJ, Treml JF, Scholz JL, Cancro MP. Manipulating B cell homeostasis: a key component in the advancement of targeted strategies. Arch Immunol Ther Exp (Warsz) 2008; 56:153-64. [PMID: 18512030 DOI: 10.1007/s00005-008-0017-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Accepted: 01/04/2008] [Indexed: 11/28/2022]
Abstract
Understanding the homeostatic mechanisms governing lymphocyte pools achieves critical importance as lymphocyte-targeted therapies expand in use and scope. The primacy of B lymphocyte stimulator (BLyS) family ligands and receptors in governing B lymphocyte homeostasis has become increasingly clear in recent years, affording insight into novel opportunities and potential pitfalls for targeted B cell therapeutics. Interclonal competition for BLyS-BR3 interactions determines the size of naïve B cell pools and can regulate the stringency of selection applied as cells complete maturation. Thus one of the predicted consequences of ablative therapies targeting primary pools is relaxed negative selection. This suggests that BLyS levels and B cell reconstitution rates may serve useful prognostic roles and that BLyS itself might be targeted to circumvent relapse. Alternatively, manipulations that allow rare, minimally autoreactive specificities to survive and mature may lead to opportunities in cases where antibody-based vaccine development has heretofore been unsuccessful. BLyS family ligands and receptors also play a role in activated and memory B cell pools, suggesting they might likewise be targeted to promote or delete particular antigen-experienced subpopulations in a similar way.
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Affiliation(s)
- Laura S Treml
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6082, USA
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12
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Affiliation(s)
- Stephen M Jackson
- Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
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13
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Spillmann FJX, Beck-Engeser G, Wabl M. Differentiation and Ig-Allele Switch in Cell Line WEHI-231. THE JOURNAL OF IMMUNOLOGY 2007; 179:6395-402. [DOI: 10.4049/jimmunol.179.10.6395] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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14
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Bernard MP, Phipps RP. CpG oligodeoxynucleotides induce cyclooxygenase-2 in human B lymphocytes: implications for adjuvant activity and antibody production. Clin Immunol 2007; 125:138-48. [PMID: 17728187 PMCID: PMC2197160 DOI: 10.1016/j.clim.2007.07.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Revised: 07/12/2007] [Accepted: 07/14/2007] [Indexed: 12/23/2022]
Abstract
Synthetic CpG oligodeoxynucleotides (ODN), similar to DNA sequences found in certain microorganisms, have shown promise as adjuvants for humans by enhancing immune responses. Since antibodies are often indicators of successful vaccination, it is important to understand how CpG ODNs affect human B cells and influence antibody production. Treatment of human B cells with synthetic CpG ODN sequences increased both steady-state Cox-2 mRNA levels and protein expression. B cell receptor stimulation in concert with CpG ODN treatment induced Cox-2 expression and production of prostaglandin E(2), well above that seen with CpG ODN alone. Importantly, CpG-induced human B cell IgM and IgG production was attenuated by dual Cox-1/Cox-2 inhibitors and Cox-2-selective inhibitors. Our findings support a key role for CpG ODN-induced human B cell Cox-2 in the production of IgM and IgG antibodies, revealing that drugs that attenuate Cox-2 activity have the potential to reduce optimal antibody response to adjuvants/vaccination.
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Affiliation(s)
- Matthew P. Bernard
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
| | - Richard P. Phipps
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
- Lung Biology and Disease Program, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
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15
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Tian C, Kron GK, Dischert KM, Higginbotham JN, Crowe JE. Low expression of the interleukin (IL)-4 receptor alpha chain and reduced signalling via the IL-4 receptor complex in human neonatal B cells. Immunology 2006; 119:54-62. [PMID: 16764687 PMCID: PMC1782340 DOI: 10.1111/j.1365-2567.2006.02405.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Diminished neonatal antibody responses following infection or immunization may stem in part from intrinsic characteristics of neonatal B cells. In this study, we used B-cell subset sorting combined with gene expression assays to investigate major differences in the expression of host genes in neonatal and adult naïve B cells. We discovered significantly reduced expression of the interleukin (IL)-4 receptor alpha chain and reduced IL-4-induced signalling in neonatal B cells. Neonatal naïve B cells were susceptible to more rapid and more profound levels of apoptosis when cultured in vitro. They also exhibited a limited response to IL-4 treatment compared with adult cells. The expression level of the IL-13 receptor alpha 1 chain, a key component of the IL-13 receptor/IL-4 type II receptor, and the response to IL-13 treatment for protection against apoptosis in neonatal B cells were similar to those of the adult B cells. These studies suggest a possible mechanism underlying the limited magnitude and durability of neonatal antibody responses.
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Affiliation(s)
- Cuixia Tian
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232-2905, USA
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16
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Ehrhardt GRA, Hsu JT, Gartland L, Leu CM, Zhang S, Davis RS, Cooper MD. Expression of the immunoregulatory molecule FcRH4 defines a distinctive tissue-based population of memory B cells. ACTA ACUST UNITED AC 2005; 202:783-91. [PMID: 16157685 PMCID: PMC2212938 DOI: 10.1084/jem.20050879] [Citation(s) in RCA: 248] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The FcRH4 transmembrane molecule, a member of the Fc receptor homologue family, can potently inhibit B cell receptor (BCR) signaling. We show that cell surface expression of this immunoregulatory molecule is restricted to a subpopulation of memory B cells, most of which lack the classical CD27 marker for memory B cells in humans. The FcRH4+ and FcRH4− memory B cells have undergone comparable levels of immunoglobulin isotype switching and somatic hypermutation, while neither subpopulation expresses the transcription factors involved in plasma cell differentiation. The FcRH4+ memory cells are morphologically distinctive large lymphocytes that express the CD69, CD80, and CD86 cell activation markers. They are also shown to be poised to secrete high levels of immunoglobulins in response to stimulation with T cell cytokines, but they fail to proliferate in response either to BCR ligation or Staphylococcus aureus stimulation. A heightened expression of the CCR1 and CCR5 chemokine receptors may facilitate their preferential localization in lymphoid tissues near epithelial surfaces. Cell surface FcRH4 expression thus marks a unique population of memory B cells with distinctive morphology, functional capabilities, and tissue localization.
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Affiliation(s)
- Götz R A Ehrhardt
- Division of Clinical and Developmental Immunology, University of Alabama at Birmingham, Birmingham, Birmingham, AL 35294, USA
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17
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Inamine A, Takahashi Y, Baba N, Miyake K, Tokuhisa T, Takemori T, Abe R. Two waves of memory B-cell generation in the primary immune response. Int Immunol 2005; 17:581-9. [PMID: 15824068 DOI: 10.1093/intimm/dxh241] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Memory B cells can be generated independently of germinal center (GC) formation and affinity maturation in Bcl-6-deficient mice, but the contribution of the GC-independent pathway for memory B-cell generation in normal mice remains unknown. To examine this, we administrated anti-inducible co-stimulator (ICOS) mAbs into mice at the onset of GC formation in the primary response. This manipulation affected the generation of GC B cells in the spleen, but neither IgG1 memory B cell nor production of IgG1 long-term antibody was affected. In ICOS-manipulated mice, GC B cells accumulated somatic mutations in the IgV(H) genes and underwent affinity maturation; however, memory B cells scarcely accumulated mutations and reconstituted the secondary response by low affinity, supporting the notion that low-affinity memory B cells are generated in a GC-independent manner. Thus, it appears that memory B cells are established by two different pathways, associated with or without GC reaction and affinity maturation. The generation and long-term persistence of low-affinity IgG1 memory B cells and antibodies in ICOS-manipulated mice support the idea that low-affinity memory B cells may give rise to long-term antibody-forming cells.
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Affiliation(s)
- Ayako Inamine
- Department of Immunology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
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18
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Jackson SM, Capra JD. IgH V-Region Sequence Does Not Predict the Survival Fate of Human Germinal Center B Cells. THE JOURNAL OF IMMUNOLOGY 2005; 174:2805-13. [PMID: 15728490 DOI: 10.4049/jimmunol.174.5.2805] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Germinal center (GC) B cell survival fate is governed in part by the outcome of successful/failed BCR-mediated interactions with accessory cells. However, the extent to which the BCR primary sequence influences such interactions is not fully understood. Over 1000 IgV(H)4 family cDNAs were sequenced from living (annexin V(-)) and apoptotic (annexin V(+) or from within tingible body macrophages) GC B cell fractions from seven tonsils. Results surprisingly demonstrate that living and dying GC B cells do not significantly differ in IgV(H), D, or J(H) gene segment use; HCDR3 length or positive charge; or mutation frequency. Additionally, equivalent IgH cDNA sequences were identified in both fractions, suggesting that BCR sequence alone is an unreliable predictor of GC B cell survival.
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Affiliation(s)
- Stephen M Jackson
- Molecular Immunogenetics, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
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19
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Grimaldi CM, Hicks R, Diamond B. B Cell Selection and Susceptibility to Autoimmunity. THE JOURNAL OF IMMUNOLOGY 2005; 174:1775-81. [PMID: 15699102 DOI: 10.4049/jimmunol.174.4.1775] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Autoreactive B cells arise routinely as part of the naive B cell repertoire. The immune system employs several mechanisms in an attempt to silence these autoreactive cells before they achieve immunocompetence. The BCR plays a central role in B cell development, activation, survival, and apoptosis, and thus is a critical component of the regulation of both protective and autoreactive B cells. The strength of signal mediated by the BCR is determined by numerous factors, both B cell intrinsic and B cell extrinsic. Perturbations in the molecules that regulate the BCR signal strength or that activate pathways that engage in cross talk with the BCR-mediated signaling pathways can lead to the aberrant survival and activation of autoreactive B cells. In this review, we will discuss the some newly identified genetic loci and factors that modulate the BCR signal transduction pathway and, therefore, the regulation of autoreactive B cells. We will also provide evidence for a model of autoreactivity in which a reduction in the strength of the BCR signal allows the survival and the modulation of a naive B cell repertoire replete with autoreactivity.
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Wykes MN, Beattie L, Macpherson GG, Hart DN. Dendritic cells and follicular dendritic cells express a novel ligand for CD38 which influences their maturation and antibody responses. Immunology 2004; 113:318-27. [PMID: 15500618 PMCID: PMC1782574 DOI: 10.1111/j.1365-2567.2004.01968.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
CD38 is a cell surface molecule with ADP-ribosyl cyclase activity, which is predominantly expressed on lymphoid and myeloid cells. CD38 has a significant role in B-cell function as some anti-CD38 antibodies can deliver potent growth and differentiation signals, but the ligand that delivers this signal in mice is unknown. We used a chimeric protein of mouse CD38 and human immunogobulin G (IgG) (CD38-Ig) to identify a novel ligand for murine CD38 (CD38L) on networks of follicular dendritic cells (FDCs) as well as dendritic cells (DCs) in the spleen. Flow-cytometry found that all DC subsets expressed cytoplasmic CD38L but only fresh ex vivo CD11c+ CD11b- DCs had cell surface CD38L. Anti-CD38 antibody blocked the binding of CD38-Ig to CD38L, confirming the specificity of detection. CD38-Ig immuno-precipitated ligands of 66 and 130 kDa. Functional studies found that CD38-Ig along with anti-CD40 and anti-major histocompatibility complex (MHC) class II antibody provided maturation signals to DCs in vitro. When CD38-Ig was administered in vivo with antigen, IgG2a responses were significantly reduced, suggesting that B and T cells expressing CD38 may modulate the isotype of antibodies produced through interaction with CD38L on DCs. CD38-Ig also expanded FDC networks when administered in vivo. In conclusion, this study has identified a novel ligand for CD38 which has a role in functional interactions between lymphocytes and DCs or FDCs.
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Affiliation(s)
- Michelle N Wykes
- Queensland Institute of Medical Research, The Bancroft Center, Herston, Australia.
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21
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Abstract
In recent years, our understanding of B-cell biology and the roles of B cells in normal immune responses and autoimmunity has increased dramatically. We no longer think of B cells simply as antibody factories. It is clear that these diverse and exquisitely regulated cells may contribute in a multitude of ways to immune responses. Animal models, clinical trials of biologic agents, and the ever expanding field of molecular biology have made great contributions to our current knowledge. With this improved understanding, we are afforded the opportunity to consider numerous potential therapeutic targets for treating autoimmune disease. As this growing science evolves, we can expect to see the advent of new therapies and new hope for patients who are afflicted with these disorders.
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Affiliation(s)
- Elena Weinstein
- Division of Rheumatology, Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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de Grandmont MJ, Racine C, Roy A, Lemieux R, Néron S. Intravenous immunoglobulins induce the in vitro differentiation of human B lymphocytes and the secretion of IgG. Blood 2003; 101:3065-73. [PMID: 12480708 DOI: 10.1182/blood-2002-06-1684] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The therapeutic effects of intravenous immunoglobulins (IVIGs) in several autoimmune diseases are characterized by a decrease in pathologic autoantibody levels. Although little direct evidence has been reported in humans, the large repertoire of natural immunoglobulin G (IgG) antibodies in IVIGs is expected to be involved in the regulation of autoreactive B lymphocytes. In normal adult mice, IVIGs have been reported to modulate immature B cells as well as peripheral B lymphocytes through V-region connections. Studies with human serum also indicated that anti-idiotypic antibodies, present in IVIG preparations, could recognize both natural and pathologic autoantibodies. We have used an in vitro culture system to characterize the direct effect of IVIGs on human B lymphocytes. This in vitro culture system involves CD40 activation of B lymphocytes by its ligand CD154 in the presence of cytokines. In this system, addition of IVIGs decreased by 50% to 80% the expansion of B lymphocytes. This reduced expansion was due to a decrease in the proliferation rate. In addition, a portion of B lymphocytes was differentiated into IgG-secreting cells in the presence of IVIGs and the secreted IgGs were reactive with antigens such as nucleoprotamine, dsDNA, tetanus toxin, and human IgG F(ab')(2) fragments. These observations indicate that IVIGs can have direct effects on B lymphocytes and suggest that such IVIG regulation of B lymphocytes could be involved in the therapeutic effects of IVIGs in autoimmune diseases.
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Abstract
Regulation of apoptosis in the B cell lineage has implications for homeostasis, quality control of the antibody response, and tolerance. In this chapter we examine the different checkpoints that control life and death decisions of B cells during the antigen-independent and antigen-dependent phases of their development. We discuss the cell death mechanism involved in elimination of unwanted B cells at different stages of their development as well as the signals that trigger or repress the apoptotic process. At the steady state, before or after development of an immune response, B cell apoptosis ensures that the antigen receptor (BCR) on newly produced B cells is functional and does not recognize self-antigens with high avidity. It also ensures that the size of the peripheral B cell compartment remains constant in spite of the continuous input of B cells from the bone marrow. All these processes are controlled by the mitochondrial death pathway and are thus perturbed by overexpression of the antiapoptotic members of the bcl-2 gene family. By contrast, the death receptor pathway plays a prominent role during the antigen-dependent phase of B cell development. Three sets of membrane molecules stand as crucial regulators of B cell survival. First, the BCR which plays a central but ambiguous role. On the one hand, it triggers death of B cells that recognize self-antigens or have been exposed to repeated antigenic stimulations. On the other hand, it promotes survival of the peripheral mature B cell pool and protects activated B cells from CD95-induced killing. Second, the death receptor Fas/CD95 which is instrumental in censoring B cells activated in a bystander fashion at the initiation of the response to T-dependent antigens. It also drives elimination of low-affinity and self-reactive B cell clones that arise through the process of somatic mutations during the germinal center reaction. As such, it contributes to the affinity maturation of the antibody response. Finally, three membrane receptors (TACI, BCMA, and BAFF-R) which bind a newly discovered member of the tumor necrosis factor family named BAFF. BAFF acts specifically on peripheral B cells but its cellular targets seem to be restricted to two splenic B cell populations: (i) transitional immature B cells and (ii) marginal zone B cells, known to be responsible for the response to thymus-independent type 2 antigens. This suggests its possible implication in positive selection of peripheral B cells and in the antibacterial B cell responses.
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Yankee TM, Solow SA, Draves KD, Clark EA. Expression of the Grb2-related protein of the lymphoid system in B cell subsets enhances B cell antigen receptor signaling through mitogen-activated protein kinase pathways. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:349-55. [PMID: 12496419 DOI: 10.4049/jimmunol.170.1.349] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Adapter proteins play a critical role in regulating signals triggered by Ag receptor cross-linking. These small molecules link receptor proximal events with downstream signaling pathways. In this study, we explore the expression and function of the Grb2-related protein of the lymphoid system (GrpL)/Grb2-related adaptor downstream of Shc adapter protein in human B cells. GrpL is expressed in naive B cells and is down-regulated following B cell Ag receptor ligation. By contrast, germinal center and memory B cells express little or no GrpL. Using human B cell lines, we detected constitutive interactions between GrpL and B cell linker protein, Src homology (SH)2 domain-containing leukocyte protein of 76 kDa, hemopoietic progenitor kinase 1, and c-Cbl. The N-terminal SH3 domain of GrpL binds c-Cbl while the C-terminal SH3 domain binds B cell linker protein and SH2 domain-containing leukocyte protein of 76 kDa. Exogenous expression of GrpL in a GrpL-negative B cell line leads to enhanced Ag receptor-induced extracellular signal-related kinase and p38 mitogen-activated protein kinase phosphorylation. Thus, GrpL expression in human B cell subsets appears to regulate Ag receptor-mediated signaling events.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Adjuvants, Immunologic/biosynthesis
- Adjuvants, Immunologic/genetics
- Adjuvants, Immunologic/metabolism
- Adjuvants, Immunologic/physiology
- B-Lymphocyte Subsets/immunology
- B-Lymphocyte Subsets/metabolism
- Carrier Proteins/biosynthesis
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Carrier Proteins/physiology
- Down-Regulation/genetics
- Down-Regulation/immunology
- GRB2 Adaptor Protein
- Humans
- Interphase/genetics
- Interphase/immunology
- Lymphocyte Activation/genetics
- Lymphoid Tissue/cytology
- Lymphoid Tissue/immunology
- Lymphoid Tissue/metabolism
- MAP Kinase Signaling System/immunology
- Mutagenesis, Site-Directed
- Palatine Tonsil
- Phosphoproteins/metabolism
- Protein Biosynthesis
- Protein Serine-Threonine Kinases/metabolism
- Proteins/physiology
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-cbl
- Receptors, Antigen, B-Cell/metabolism
- Receptors, Antigen, B-Cell/physiology
- Tumor Cells, Cultured
- Ubiquitin-Protein Ligases
- src Homology Domains/genetics
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Affiliation(s)
- Thomas M Yankee
- Department of Microbiology, University of Washington, Seattle WA 98195, USA.
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25
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Indraccolo S, Minuzzo S, Zamarchi R, Calderazzo F, Piovan E, Amadori A. Alternatively spliced forms of Igalpha and Igbeta prevent B cell receptor expression on the cell surface. Eur J Immunol 2002; 32:1530-40. [PMID: 12115635 DOI: 10.1002/1521-4141(200206)32:6<1530::aid-immu1530>3.0.co;2-#] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The B cell antigen receptor (BCR) includes an Igalpha/Igbeta heterodimer non-covalently associated with surface immunoglobulin. Recently, variant Igalpha and Igbeta transcripts, arising from alternative mRNA splicing, have been reported. The present study examined the function of the potential products of these transcripts, by utilizing cDNA expression plasmids to reconstitute human BCR expression in transfected 293T cells. Spliced transcripts produced truncated proteins (deltaIgalpha and deltaIgbeta), that failed to form heterodimers with their full-length counterparts, and did not mediate transport of IgM to the cell surface. When overexpressed, both deltaIgalpha and deltaIgbeta acted as competitors of Igalpha and Igbeta, leading to down-modulated surface IgM expression, and retention of IgM in the endoplasmic reticulum. These findings document a possible novel mechanism for controlling BCR expression in B cells, based on up-regulated synthesis of components devoid of transport function.
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Affiliation(s)
- Stefano Indraccolo
- Department of Oncology and Surgical Sciences, Interuniversity Center for Research on Cancer, University of Padova, Padova, Italy.
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Kronfeld I, Kazimirsky G, Gelfand EW, Brodie C. NGF rescues human B lymphocytes from anti-IgM induced apoptosis by activation of PKCzeta. Eur J Immunol 2002; 32:136-43. [PMID: 11754354 DOI: 10.1002/1521-4141(200201)32:1<136::aid-immu136>3.0.co;2-t] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Nerve growth factor (NGF) is a neurotrophic factor acting on both the peripheral and central nervous systems. In addition, it has been shown to modulate B lymphocyte function through receptors consisting of both p75 and TrkA proteins. The low-affinity NGFR, p75, shares structural homology with the B cell antigen, CD40, tumor necrosis factor (TNF) receptor and Fas antigen (APO-1), which play a role in cell apoptosis. We studied the effect of NGF on anti-IgM-induced apoptosis in human B lymphocytes and the role of protein kinase C (PKC) in this effect. Incubation of Ramos cells with anti-IgM (10 microg/ml) induced apoptosis which was observed after 6 h and reached plateau levels after 24 h. Addition of NGF to anti-IgM-treated cells rescued cells from apoptosis. The NGF effect was blocked by anti-NGF antibody and by K252a, a specific inhibitor for the tyrosine kinase activity of TrkA. NGF induced translocation of PKCdelta and PKCalpha from the cytosol to the plasma membrane and translocation of PKCzeta to the nucleus. To examine the role of PKC in the inhibitory effect of NGF on anti-IgM-induced apoptosis, we used inhibitors of PKCalpha and PKCdelta and found that these treatments did not alter the NGF effect. In contrast, treatment of the cells with oligonucleotide antisense directed against the 5' coding sequence of PKCzeta reduced the expression of PKCzeta in the cells and abolished the protective effect of NGF on anti-IgM-induced apoptosis. The translocation of PKCzeta and the protective effect of NGF were inhibited by the phosphatidylinositol 3 (PI3)-kinase inhibitors wortmannin and LY294002. The results of this study indicate that NGF is involved in B cell survival and that this effect is mediated by PI3-kinase-dependent activation of PKCzeta.
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Affiliation(s)
- Ilana Kronfeld
- Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
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Reparon-Schuijt CC, van Esch WJ, van Kooten C, Ezendam NP, Levarht EW, Breedveld FC, Verweij CL. Presence of a population of CD20+, CD38- B lymphocytes with defective proliferative responsiveness in the synovial compartment of patients with rheumatoid arthritis. ARTHRITIS AND RHEUMATISM 2001; 44:2029-37. [PMID: 11592364 DOI: 10.1002/1529-0131(200109)44:9<2029::aid-art352>3.0.co;2-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To provide a comprehensive understanding of the humoral immune response that takes place at the site of inflammation in rheumatoid arthritis (RA), we studied the functional properties of synovial B cells. In particular, the response to various modes of mitogen stimulation was investigated. METHODS Purified synovial fluid (SF) B cells were cultured in the presence of CD40 ligand (CD40L)-expressing fibroblasts and cytokines, activated T cells, or phorbol myristate acetate (PMA)/ionomycin. Proliferation was determined by 3H-thymidine incorporation. Release of intracellular calcium was studied by flow cytometry. RESULTS The inflamed joints of RA patients contained a population of CD20+,CD38- B cells with dramatically impaired mitogen responsiveness. Although the Ig-producing capacity was intact, these cells failed to proliferate in response to (a) CD40 in the presence of interleukin-2 (IL-2) and IL-10, (b) activated T cells, or (c) stimulation via the B cell receptor. Moreover, SF CD20+,CD38- B cells revealed a defective B cell receptor-induced Ca2+ influx, reminiscent of anergic B cells. Release of intracellular Ca2+ by ionomycin in the presence of the protein kinase C activator PMA did not restore the proliferative capacity. These findings indicate blockades in the proximal and distal intermediates involved in mitogen signaling. CONCLUSION SF CD20+,CD38- B cells have functionally impaired proliferative responsiveness. The capacity of these cells to respond to activation by the production of Ig supports the notion that these cells might serve as Ig-producing effector cells and, as such, play a role in the pathophysiology of RA.
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Vidal-Rubio B, Sanchez-Carril M, Oliver-Morales J, González-Femandez Á, Gambón-Deza F. Changes in human lymphocyte subpopulations in tonsils and regional lymph nodes of human head and neck squamous carcinoma compared to control lymph nodes. BMC Immunol 2001; 2:2. [PMID: 11316463 PMCID: PMC31349 DOI: 10.1186/1471-2172-2-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2001] [Accepted: 04/10/2001] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Lymphoid tissues constitute basic structures where specific immune responses take place. This leads to the development of germinal centres (GCs), migration of cells and the generation of memory cells. Here, we have compared human tumour reactive lymph nodes and tonsils with control lymph nodes. RESULTS The study by flow cytometry shows that in control lymph nodes the majority of cells were naive T-lymphocytes (CD45RA+/CD7+). In reactive nodes, although the percentage of CD45RO+ T cells remains constant, there is an increase in the number of B-lymphocytes, and a reduction in naive T cells. The percentage of cells expressing CD69 was similar in reactive nodes and in controls. In both cases, we have found two populations of B cells of either CD69- or CD69dull. Two populations of T cells, which are either negative for CD69 or express it in bright levels (CD69bright), were also found. The analysis of tissue sections by confocal microscopy revealed differences between control, tonsils and tumor reactive lymph nodes. In control lymph nodes, CD19 B cells are surrounded by a unique layer of CD69bright/CD45RO+ T cells. GCs from tonsils and from tumour reactive nodes are mainly constituted by CD19 B cells and have four distinct layers. The central zone is composed of CD69- B cells surrounded by CD69bright/CD45RO+ T cells. The mantle region has basically CD69dull B-lymphocytes and, finally, there is an outer zone with CD69-/CD45RO+ T cells. CONCLUSIONS Human secondary lymphoid organs react with an increase in the proportion of B lymphocytes and a decrease in the number of CD45RA+ T cells (naive). In tonsils, this is due to chronic pathogen stimulation, whereas in lymph nodes draining head and neck carcinomas the reaction is prompted by surrounded tumors. During this process, secondary lymphoid organs develop secondary follicles with a special organization of T and B cells in consecutive layers, that are described here by confocal microscopy. This pattern of cellular distribution may suggest a model of cell migration into the secondary lymphoid follicles.
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29
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Tokuhisa T, Hatano M, Okada S, Fukuda T, Kunimasa I. Transcriptional regulation of memory B cell development. Mod Rheumatol 2001; 11:1-5. [PMID: 24387012 DOI: 10.3109/s101650170035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract Antigen-reactive B cells in the spleen of mice immunized with T cell-dependent antigens generate antibody-producing foci in periarteriolar lymphoid sheaths (PALS) or migrate into follicles to form germinal centers. Germinal center B cells clonally expand, have somatic hypermutation in IgV-region genes, are selected by apoptosis on the basis of antigen-specific signals, and differentiate to memory B cells. Two transcription factors (Bcl6 and c-Fos) in B cells play a critical role in the development of germinal centers. (1) Bcl6 is highly expressed in germinal center B cells, and defects in B cells perturb the formation of germinal centers but not that of PALS-associated foci, indicating the essential role of Bcl6 in the differentiation. (2) Overexpression of c-Fos in germinal center B cells induces apoptosis and perturbs the formation of memory B cells. Overexpression of Bcl-2 cannot rescue c-Fos-induced apoptosis in germinal center B cells. Since c-Fos is induced in mature B cells which have reacted with antigens, and clonal deletion of self-reactive B cells is insensitive to overexpression of Bcl-2, c-Fos may play a causal role in the clonal deletion of germinal center B cells. Thus, these factors provide a unique opportunity to investigate the molecular mechanisms of memory B cell development.
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Affiliation(s)
- T Tokuhisa
- Department of Developmental Genetics, Chiba University Graduate School of Medicine , 1-8-1 Inohana, Chuo-ku, Chiba 260-8670 , Japan
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30
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Guilliano MJ, Foxx-Orenstein AE, Lebman DA. The microenvironment of human Peyer's patches inhibits the increase in CD38 expression associated with the germinal center reaction. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:2179-85. [PMID: 11160270 DOI: 10.4049/jimmunol.166.4.2179] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Analysis of B cells in the human tonsils identified CD38 expression as a hallmark of germinal center (GC) B cells. However, the signals responsible for the in vivo induction of CD38 have not been determined. The primary site for generation of memory and plasma cells in the gastrointestinal tract is the GCs of Peyer's patches (PP). PP and intestinal mucosa, but not tonsils or oral mucosa, express mucosal addressin cell adhesion molecule-1 (MAdCAM-1). The ligand for MAdCAM-1, integrin alpha(4)beta(7), is expressed on naive B cells and memory B cells that traffic to the gastrointestinal tract. In this study we determine that, unlike tonsil, human PP GC B cells do not express significant levels of CD38. PP B cells can be induced to express CD38 upon culture with CD40 ligand, anti-B cell receptor, and IFN-gamma. However, coculture of tonsil naive B cells with an Ab directed against integrin beta(7) inhibits IFN-gamma-induced CD38 hyperexpression. The absence of CD38 on PP GCs suggests that there are tissue-specific pathways of B cell development that differ between tonsil and PP. The differential expression pattern of MAdCAM-1, together with the observation that ligation of beta(7) can inhibit the induction of CD38 expression, suggests that ligation of alpha(4)beta(7) in vivo may contribute to a PP-specific GC phenotype.
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Affiliation(s)
- M J Guilliano
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA 23298, USA
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31
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Wagner EF, Hanna N, Fast LD, Kouttab N, Shank PR, Vazquez A, Sharma S. Novel diversity in IL-4-mediated responses in resting human naive B cells versus germinal center/memory B cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:5573-9. [PMID: 11067912 DOI: 10.4049/jimmunol.165.10.5573] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Recent studies have defined several phenotypic and molecular changes associated with the maturation of naive human B cells within the milieu of germinal centers. Although naive B cells serve as natural precursors to germinal center (GC)/memory (M) subpopulations, little is known about the physiological requirements for the survival of the naive B cell pool in the absence of cell-cell contact or Ag-mediated activation. Because IL-4 induces expression of several membrane receptors such as CD23 which are uniquely present on resting human naive B lymphocytes, we hypothesized that these cells might be intrinsically programmed to respond to IL-4 in the absence of cell division. Using buoyant density-dependent isolation and further enrichment by negative/positive selection of human naive and GC/M subpopulations, we characterized cytokine receptor moieties on these cells and analyzed their survival and growth in the presence of IL-4 or IL-10. Resting naive B cells expressed significantly higher IL-4 receptor alpha-chain on their cell surface than the combined GC/M subpopulation. The IL-10 receptor and the IL-2 receptor gammac chain were almost equally expressed on both subpopulations. When cultured in vitro, the addition of IL-4, but not IL-10, protected naive B cells from apoptosis in the absence of activation and growth. However, IL-4 exerted no such effect on resting GC/M B cells. These data support the hypothesis that IL-4 plays a pivotal role in the survival and maintenance of resting human naive B cells.
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Affiliation(s)
- E F Wagner
- Departments of Pediatrics and Pathology, Women & Infants' Hospital and Department of Medicine, Rhode Island Hospital, Brown University, Providence, RI 02905, USA
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Tarlinton DM, Smith KG. Dissecting affinity maturation: a model explaining selection of antibody-forming cells and memory B cells in the germinal centre. IMMUNOLOGY TODAY 2000; 21:436-41. [PMID: 10953095 DOI: 10.1016/s0167-5699(00)01687-x] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Until recently, the relationship between apoptosis, selection in the germinal centre (GC) and production of high-affinity antibody-forming cells (AFCs) and memory B cells has been unclear. Here, Tarlinton and Smith present a model that accounts for the switch in GC production from high-affinity AFCs to memory B cells, and explain how Bcl-2, an inhibitor of apoptosis, can influence memory cells but not bone marrow AFCs.
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Affiliation(s)
- D M Tarlinton
- The Walter and Eliza Hall Institute for Medical Research, PO Royal Melbourne Hospital, Victoria 3050, Australia.
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Barker J, Verfaillie CM. A novel in vitro model of early human adult B lymphopoiesis that allows proliferation of pro-B cells and differentiation to mature B lymphocytes. Leukemia 2000; 14:1614-20. [PMID: 10995008 DOI: 10.1038/sj.leu.2401869] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To develop a model of early human adult B lymphopoiesis, we cultured CD34+CD38+CD10+ pro-B cells in contact with AFT024 stroma in X-VIVO10 media with 5% serum. The cytokines FLT3L + SCF + IL7 + IGF1 were added at day 0, IL4 + IL5 + IL6 + IL10 and soluble CD40 ligand at day 14, and Staph. aureus Cowan particles on day 21. Greater than 25-fold expansion of CD34+CD38+CD10+ cells was seen at 2 weeks, the majority being CD34-CD19+ pre-B cells. Differentiation to immature IgM+ B cells was seen at 3 weeks and mature IgD+ B cells at 4 weeks, with secretion of IgM into the media. Immature and mature B cells could also be generated from culture of CD34+CD10+CD19- and CD34+CD10+CD19+ cells under similar conditions. In conclusion, we have demonstrated in vitro differentiation of early pro-B cells, and possibly common lymphoid progenitor cells, to mature B cells. Additional stimuli, provided by T helper cells or dendritic cells for example, may be required for the generation of IgG+ B cells or plasma cells. However, our culture system should be a valuable tool to further investigate B cell biology and B cell malignancies such as multiple myeloma and lymphoma.
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Affiliation(s)
- J Barker
- Department of Medicine, University of Minnesota, Minneapolis, USA
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Morgan JW, Kouttab N, Ford D, Maizel AL. Vitamin D-mediated gene regulation in phenotypically defined human B cell subpopulations. Endocrinology 2000; 141:3225-34. [PMID: 10965893 DOI: 10.1210/endo.141.9.7666] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Isolation of distinct subpopulations of density-fractionated normal human B lymphocytes reveals that the requirements for up-regulation of the vitamin D receptor (VDR) and initiation of 1alpha,25-dihydroxyvitamin D3 [1alpha,25-(OH)2D3]-mediated genomic trans-activation are dependent upon the state of cellular activation. The kinetics of the response differ widely among these B cell subpopulations. However, these density-fractionated B cell subpopulations are phenotypically diverse and therefore are not representative of distinct stages of B cell maturation and differentiation. To examine the role of B cell differentiation on the induction and maintenance of biological receptivity to 1,25-(OH)2D3, we purified naive, germinal center, and memory B cells based on their expression of CD38 and CD44 surface antigens and surface Ig isotype. These phenotypically defined B cell subpopulations were all found to constitutively express VDR, and all exhibited similar activation requirements and kinetics for initiation of 1,25(OH)2D3-mediated genomic trans-activation. Taken together, these results suggest that defined stages of differentiation in normal B cells are not significant predicators of VDR expression or receptivity to 1,25-(OH)2D3. Rather, the degree of cellular activation, regardless of maturation stage, determines whether the effects of this immunoregulatory hormone will influence a mature B lymphocyte.
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Affiliation(s)
- J W Morgan
- Department of Pathology, Roger Williams Hospital, Providence, Rhode Island 02908, USA.
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35
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Choe J, Li L, Zhang X, Gregory CD, Choi YS. Distinct role of follicular dendritic cells and T cells in the proliferation, differentiation, and apoptosis of a centroblast cell line, L3055. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:56-63. [PMID: 10604993 DOI: 10.4049/jimmunol.164.1.56] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Germinal center (GC) B cells undergo complex interactions with follicular dendritic cells (FDC) and T cells in the course of differentiation into memory B and plasma cells. To delineate the individual roles of FDC and T cells at each stage of GC B cell differentiation at the clonal level and to analyze the signals involved, we adopted a unique experimental model using an FDC line, HK, and a lymphoma cell line, L3055, that resembles centroblasts. A detailed phenotypic analysis revealed L3055 cells to be a clonal population originating from the GC. Like freshly isolated centroblasts, L3055 cells underwent spontaneous apoptosis when cultured in the absence of fresh FDC or HK cells. L3055 cells proliferated continuously in the presence of HK cells, while they differentiated into a population with the phenotype of centrocytes after stimulation with CD40 ligand (CD40L) and IL-4. The CD40L-stimulated L3055 cells underwent CD95-mediated apoptosis, which was reminiscent of the feature of CD40L-stimulated tonsillar GC B cells. In contrast to HK cells that did not protect L3055 cells from anti-Ig killing, CD40L plus IL-2, IL-4, and IL-10 prevented anti-Ig-induced apoptosis. These experimental results demonstrate a distinct function of FDC and activated T cells, in that FDC provide signals for rapid proliferation of centroblasts, whereas T cells confer signals for differentiation of centroblasts into centrocytes and resistance to B cell receptor-mediated apoptosis. T cells collaborate with FDC in the protection and expansion of the Ag-specific GC B cells.
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Affiliation(s)
- J Choe
- Laboratory of Cellular Immunology, Alton Ochsner Medical Foundation, New Orleans, LA 70121, USA
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36
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Berard M, Mondière P, Casamayor-Pallejà M, Hennino A, Bella C, Defrance T. Mitochondria Connects the Antigen Receptor to Effector Caspases During B Cell Receptor-Induced Apoptosis in Normal Human B Cells. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.9.4655] [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
We have previously reported that CD40 stimulation sensitizes human memory B cells to undergo apoptosis upon subsequent B cell receptor (BCR) ligation. We have proposed that activation stimuli connect the BCR to an apoptotic pathway in mature B cells and that BCR-induced apoptosis of activated B cells could serve a similar function as activation-induced cell death in the mature T cell compartment. Although it has been reported that caspases are activated during this process, the early molecular events that link the Ag receptor to these apoptosis effectors are largely unknown. In this study, we report that acquisition of susceptibility to BCR-induced apoptosis requires entry of memory B cells into the S phase of the cell cycle. We also show that transduction of the death signal via the BCR sequentially proceeds through a caspase-independent and a caspase-dependent phase, which take place upstream and downstream of the mitochondria, respectively. Furthermore, our data indicate that the BCR-induced alterations of the mitochondrial functions are involved in activation of the caspase cascade. We have found both caspases-3 and -9, but not caspase-8, to be involved in the BCR apoptotic pathway, thus supporting the notion that initiation of the caspase cascade could be under the control of the caspase-9/Apaf-1/cytochrome c multimolecular complex. Altogether, our findings establish the mitochondria as the connection point through which the Ag receptor can trigger the executioners of apoptotic cell death in mature B lymphocytes.
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Affiliation(s)
- Marion Berard
- Institut National de la Santé et de la Recherche Médicale U404, Immunité et Vaccination, Lyon, France
| | - Paul Mondière
- Institut National de la Santé et de la Recherche Médicale U404, Immunité et Vaccination, Lyon, France
| | | | - Ana Hennino
- Institut National de la Santé et de la Recherche Médicale U404, Immunité et Vaccination, Lyon, France
| | - Chantal Bella
- Institut National de la Santé et de la Recherche Médicale U404, Immunité et Vaccination, Lyon, France
| | - Thierry Defrance
- Institut National de la Santé et de la Recherche Médicale U404, Immunité et Vaccination, Lyon, France
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37
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Keenan C, Thompson S, Knox K, Pears C. Protein kinase C-alpha is essential for Ramos-BL B cell survival. Cell Immunol 1999; 196:104-9. [PMID: 10527562 DOI: 10.1006/cimm.1999.1549] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Ramos-Burkitt lymphoma (BL) B cell line is driven into growth arrest and apoptosis by cross-linking surface immunoglobulin. We demonstrate that protein kinase C (PKC) activity is required for Ramos B cell proliferation and survival. A variety of PKC inhibitors trigger a significant decrease in [(3)H]thymidine incorporation with a concomitant increase in cell death. Antisense depletion of expression of the PKC-alpha isoform is sufficient to trigger cell death in the absence of any other signal, demonstrating a requirement for this isoform for survival of Ramos-BL B cells. Cross-linking surface immunoglobulin also leads to depletion of PKC-alpha levels, suggesting that this may be one mechanism by which this signals for cell death in Ramos-BL B cells.
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Affiliation(s)
- C Keenan
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
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38
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Surface Molecule Loss and Bleb Formation by Human Germinal Center B Cells Undergoing Apoptosis: Role of Apoptotic Blebs in Monocyte Chemotaxis. Blood 1999. [DOI: 10.1182/blood.v94.3.1012.415k05_1012_1020] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human tonsil germinal center (GC) B cells rapidly undergo apoptosis in culture. Annexin-V binding shows an early event in this process. In the present study, this method has been used to label apoptotic GC B cells and to analyze additional surface molecules. The expression of all of the molecules studied was reduced in apoptotic (annexin-V+) GC B cells, and the reduction was more marked for CD11a, CD21, CD22, CD49d, and CD54, molecules that participate in survival interaction for GC B cells. The analysis of CD54, one of the molecules that was more drastically reduced, showed that GC, but not mantle zone, B cells actively secrete CD54 to the culture supernatant (SN). The secreted CD54 was partly released from the GC B cells in a particulate form as demonstrated by centrifugation. Further experiments using filtration, fluorescence microscopy, electron microscopy, and flow cytometry analysis showed that GC B cells released to the culture SN a population of spherical membranous vesicles of about 0.18 μm in size, similar to the blebs described in other apoptosis systems. Bleb formation depended on active metabolism, Ca2+, and, in part, on microfilament integrity. GC B-cell–derived blebs were clearly associated with apoptosis, as antiapoptotic stimuli prevented their formation. In addition, GC B-cell–derived blebs contained the adhesion molecules previously studied. Consequently, bleb formation might contribute to the surface molecule loss occurring in apoptotic GC B cells. Finally, a chemotaxis assay showed that GC B-cell blebs were chemotactic for human monocytes, suggesting that this mechanism might operate in vivo.
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39
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Su L, David M. Inhibition of B Cell Receptor-Mediated Apoptosis by IFN. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.162.11.6317] [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
IFNs are a family of cytokines that are involved in the regulation of immune and inflammatory responses. Clinical use of IFN-α/β encompasses treatment for a variety of diseases; however, prolonged exposure to IFN-α/β results in elevated levels of autoreactive Abs. In this study, we investigated the potential of IFNs to modulate apoptotic signals in B cells. We demonstrate that IFN-α or IFN-β inhibit Ag receptor-mediated apoptosis in a dose-dependent manner. Inhibition of phosphatidylinositol 3′ (PI3)-kinase did not abolish the effect of IFN, indicating that the antiapoptotic mechanism is PI3-kinase- and protein kinase B/Akt-independent. Instead, IFN-α and IFN-β, but not IFN-γ, significantly increase the levels of the survival protein Bcl-2, and to a lesser extent, Bcl-xL expression. Thus, IFN-α/β-mediated inhibition of B cell Ag receptor-triggered apoptosis may offer a model for the process that leads to the escape of self-reactive B cells from negative selection and consequently results in autoantibody production.
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Affiliation(s)
- Leon Su
- Department of Biology and University of California, San Diego, Cancer Center, La Jolla, CA 92093
| | - Michael David
- Department of Biology and University of California, San Diego, Cancer Center, La Jolla, CA 92093
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40
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Inada K, Okada S, Phuchareon J, Hatano M, Sugimoto T, Moriya H, Tokuhisa T. c-Fos Induces Apoptosis in Germinal Center B Cells. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.8.3853] [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
We examined the role of c-Fos in the differentiation of mature B cells into IgG-producing cells using transgenic mice carrying the c-fos gene under the control of the IFN-α/β-inducible Mx promoter (Mx-c-fos) or the constitutive H-2Kb promoter (H2-c-fos). Splenic B cells from Mx-c-fos mice were cultured with LPS and rIL-4, and IgG1+ B cells were developed in the culture after day 3. When IFN-α/β was added to the culture from day 2, development of IgG1+ B cells was perturbed, and the number of apoptotic cells increased within 24 h, suggesting that c-Fos induces apoptosis in Ig class-switching B cells. To confirm the effect of c-Fos on B cell differentiation in vivo, H2-c-fos mice were immunized with DNP-OVA. The mice produced primary IgM, but not IgG, anti-DNP Ab in serum and failed to generate germinal centers in spleen. The perturbation of germinal center formation in H2-c-fos mice was rescued by mating them with transgenic mice carrying the bcl-2 gene with the Ig promoter. However, primary IgG1 anti-DNP Ab production was still suppressed in doubly transgenic mice, suggesting that Bcl-2 can delay the time of c-Fos-induced apoptosis in Ig class-switching B cells but cannot rescue the death. Since c-Fos is induced in mature B cells reacted with Ags, and clonal deletion of self-reactive B cells in germinal centers is insensitive to Bcl-2, these results suggest that c-Fos plays a causal role in clonal deletion of germinal center B cells.
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Affiliation(s)
- Kunimasa Inada
- *Department of Developmental Genetics, Chiba University Graduate School of Medicine, Chiba, Japan; and
- †Department of Orthopedics, Chiba University School of Medicine, Chiba, Japan
| | - Seiji Okada
- *Department of Developmental Genetics, Chiba University Graduate School of Medicine, Chiba, Japan; and
| | - Janyaporn Phuchareon
- *Department of Developmental Genetics, Chiba University Graduate School of Medicine, Chiba, Japan; and
| | - Masahiko Hatano
- *Department of Developmental Genetics, Chiba University Graduate School of Medicine, Chiba, Japan; and
| | - Toyohiko Sugimoto
- *Department of Developmental Genetics, Chiba University Graduate School of Medicine, Chiba, Japan; and
| | - Hideshige Moriya
- †Department of Orthopedics, Chiba University School of Medicine, Chiba, Japan
| | - Takeshi Tokuhisa
- *Department of Developmental Genetics, Chiba University Graduate School of Medicine, Chiba, Japan; and
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41
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Abstract
Information is increasingly available concerning the molecular events that occur during primary and antigen-dependent stages of B cell development. In this review the roles of transcription factors and coactivators are discussed with respect to changes in expression patterns of various genes during B cell development. Transcriptional regulation is also discussed in the context of developmentally regulated immunoglobulin gene V(D)J recombination, somatic hypermutation, and isotype switch recombination.
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Affiliation(s)
- A Henderson
- Department of Veterinary Science, Pennsylvania State University, University Park 16802, USA.
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42
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Bleul CC, Schultze JL, Springer TA. B lymphocyte chemotaxis regulated in association with microanatomic localization, differentiation state, and B cell receptor engagement. J Exp Med 1998; 187:753-62. [PMID: 9480985 PMCID: PMC2212170 DOI: 10.1084/jem.187.5.753] [Citation(s) in RCA: 213] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/1997] [Revised: 12/09/1997] [Indexed: 02/06/2023] Open
Abstract
Migration of mature B lymphocytes within secondary lymphoid organs and recirculation between these sites are thought to allow B cells to obtain T cell help, to undergo somatic hypermutation, to differentiate into effector cells, and to home to sites of antibody production. The mechanisms that direct migration of B lymphocytes are unknown, but there is evidence that G protein-coupled receptors, and possibly chemokine receptors, may be involved. Stromal cell- derived factor (SDF)-1alpha is a CXC chemokine previously characterized as an efficacious chemoattractant for T lymphocytes and monocytes in peripheral blood. Here we show with purified tonsillar B cells that SDF-1alpha also attracts naive and memory, but not germinal center (GC) B lymphocytes. Furthermore, GC B cells could be converted to respond to SDF-1alpha by in vitro differentiation into memory B lymphocytes. Conversely, the migratory response in naive and memory B cells was significantly reduced after B cell receptor engagement and CD40 signaling. The receptor for SDF-1, CXC chemokine receptor 4 (CXCR4), was found to be expressed on responsive as well as unresponsive B cell subsets, but was more rapidly downregulated on responsive cells by ligand. Finally, messenger RNA for SDF-1 was detected by in situ hybridization in a layer of cells surrounding the GC. These findings show that responsiveness to the chemoattractant SDF-1alpha is regulated during B lymphocyte activation, and correlates with positioning of B lymphocytes within a secondary lymphoid organ.
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Affiliation(s)
- C C Bleul
- The Center for Blood Research and Harvard Medical School, Department of Pathology, Boston, Massachusetts 02115, USA
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43
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Axcrona K, Akerblad P, Leanderson T. Phenotypic convergence and divergence of surface immunoglobulin and CD40 signals. Scand J Immunol 1998; 47:210-7. [PMID: 9519858 DOI: 10.1046/j.1365-3083.1998.00295.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Both anti-CD40 antibodies and anti-immunoglobulin (Ig) coupled to Sepharose induced proliferation of resting B cells and suppressed lipopolysaccharide (LPS)-induced B-cell differentiation to immunoglobulin secretion at comparable levels determined with the plaque-forming assay and Ig RNA steady state levels. Anti-CD40 antibodies also increased the proliferation of B cells stimulated by T helper cells in vitro while suppressing their differentiation to Ig secretion. Further, B cells preactivated by anti-Ig, anti-CD40 or a combination of the two mitogens could be restimulated by anti-CD40 but not by anti-Ig antibodies. Phenotypic divergence of Ig and CD40 signals regarding surface expression of activation markers was observed. Restimulation of anti-Ig- or anti-CD40-prestimulated cells with anti-Ig induced apoptosis whereas apoptosis could be inhibited when cells were recultivated with anti-CD40.
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Affiliation(s)
- K Axcrona
- Department of Cell and Molecular Biology, Lund University, Sweden
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44
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Grafton G, Goodall M, Gregory CD, Gordon J. Mechanisms of antigen receptor-dependent apoptosis of human B lymphoma cells probed with a panel of 27 monoclonal antibodies. Cell Immunol 1997; 182:45-56. [PMID: 9427809 DOI: 10.1006/cimm.1997.1205] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The present study has used a panel of 23 monoclonal antibodies to IgM and 4 to IgD in order to probe parameters influencing sIg-dependent apoptosis in an IgM/IgD-expressing Burkitt lymphoma line. No direct correlation was observed between the capacity of the different anti-mu to drive cells into apoptosis and either their domain specificity or their affinity for sIgM. There was, however, a direct correlation between the functional outcome and the ability of the monoclonal antibodies to elicit a rise in intracellular Ca2+. For apoptosis to occur, the Ca2+ response had to attain a threshold value of approximately 100 nM. A direct role for Ca2+ in the delivery of the apoptotic signal was demonstrated using thapsigargin to raise intracellular Ca2+ levels. Antigen receptor ligation was linked to Ca2+ increases by tyrosine kinases as revealed by direct analysis of protein tyrosine phosphorylation and the effects of selective protein tyrosine kinase-inhibiting tyrphostins. These findings reveal a central role for the antigen receptor-generated Ca2+ signal in driving apoptosis in human B lymphoma cells and stresses the need to use a panel of reagents when probing function with presumed ligand-mimetic monoclonal antibodies.
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Affiliation(s)
- G Grafton
- Department of Immunology, Medical School, University of Birmingham, Edgbaston, UK
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45
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Kuo P, Alban A, Gebhard D, Diamond B. Overexpression of bcl-2 alters usage of mutational hot spots in germinal center B cells. Mol Immunol 1997; 34:1011-8. [PMID: 9488052 DOI: 10.1016/s0161-5890(97)00117-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Bcl-2 is an anti-apoptotic gene important in B cell development. In order to study how apoptosis regulates somatic hypermutation and selection of B cell clones in the germinal center, we examined the antibody response to phosphorylcholine (PC) in transgenic mice overexpressing bcl-2 in the B cell compartment. The anti-PC antibody response is dominated by the S107V1 variable region heavy chain gene. We, therefore, analyzed S107V1-encoded heavy chains from germinal center cells. The proportion of germinal center sequences that were mutated, and the frequency of mutations did not differ significantly between the two groups of mice. No significant differences were found in the clustering of replacement mutations in the complementarity determining regions (CDRs) and in replacement to silent (R:S) mutation ratios. A significant difference between bcl-2 transgenic mice and controls, however, was found in the targeting of mutations to oligonucleotide motifs presumed to be mutational "hot spots." While non-transgenic mice displayed the expected clustering of mutations in hot spots, mutations from bcl-2 transgenic mice lacked this pattern. This observation suggests that the mechanism for somatic hypermutation includes two distinct functions, a non-specific mutational apparatus and a mechanism to target mutation to hot spots, and that in certain circumstances these functions may be uncoupled.
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Affiliation(s)
- P Kuo
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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46
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Abstract
We analyzed herein whether antibodies to HLA class I α1 domain, which trigger apoptosis of activated T cells, may also control the growth/survival of human B lymphocytes. Addition of monoclonal antibody (MoAb) 90 (mouse IgG1) or YTH862 (rat IgG2b) was found to strongly inhibit the proliferation of CD40-activated total tonsil B cells as well as that of purified naive, germinal center, and memory B-cell subsets. This inhibitory effect was not prevented by addition of B-cell tropic factors, such as interleukin-2 (IL-2), IL-4, and IL-10, and was a result of induced B-cell apoptosis as shown by using a TUNEL assay and DNA electrophoresis. In contrast, engagement of another epitope of the α1 domain, as well as that of the α2 and α3 domains by specific anti-HLA class I MoAbs, failed to inhibit DNA synthesis and to induce apoptosis of CD40-activated B cells. As recently reported for acquisition of sensitivity to Fas (APO-1/CD95) -dependent apoptosis, susceptibility to MoAb90-and YTH862-induced death was restricted to CD40-activated B cells, because resting and anti–IgM-activated B cells did not undergo apoptosis after HLA class I engagement. Moreover, ligation of the B-cell receptor protected CD40-activated B cells from both HLA class I- and Fas-mediated growth inhibition and apoptosis. Taken together, these results show that engagement of the α1 domain of HLA class I induces apoptotic cell death of CD40-activated, but not of antigen-activated B cells, and would, therefore, suggest a possible role for HLA class I molecules in the control of B-cell homeostasis.
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47
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Abstract
Abstract
We analyzed herein whether antibodies to HLA class I α1 domain, which trigger apoptosis of activated T cells, may also control the growth/survival of human B lymphocytes. Addition of monoclonal antibody (MoAb) 90 (mouse IgG1) or YTH862 (rat IgG2b) was found to strongly inhibit the proliferation of CD40-activated total tonsil B cells as well as that of purified naive, germinal center, and memory B-cell subsets. This inhibitory effect was not prevented by addition of B-cell tropic factors, such as interleukin-2 (IL-2), IL-4, and IL-10, and was a result of induced B-cell apoptosis as shown by using a TUNEL assay and DNA electrophoresis. In contrast, engagement of another epitope of the α1 domain, as well as that of the α2 and α3 domains by specific anti-HLA class I MoAbs, failed to inhibit DNA synthesis and to induce apoptosis of CD40-activated B cells. As recently reported for acquisition of sensitivity to Fas (APO-1/CD95) -dependent apoptosis, susceptibility to MoAb90-and YTH862-induced death was restricted to CD40-activated B cells, because resting and anti–IgM-activated B cells did not undergo apoptosis after HLA class I engagement. Moreover, ligation of the B-cell receptor protected CD40-activated B cells from both HLA class I- and Fas-mediated growth inhibition and apoptosis. Taken together, these results show that engagement of the α1 domain of HLA class I induces apoptotic cell death of CD40-activated, but not of antigen-activated B cells, and would, therefore, suggest a possible role for HLA class I molecules in the control of B-cell homeostasis.
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48
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Abstract
CD40 is a cell surface receptor that belongs to the tumor necrosis factor receptor family. It was first identified and functionally characterized on B lymphocytes; however, in recent years it has become clear that CD40 expression is much broader, as it is found on monocytes, dendritic cells, hematopoietic progenitors, endothelial cells and epithelial cells. Although initially identified for its activation properties, CD40 is also able to transduce negative signals in various cell types. It is presently accepted that CD40 plays a critical role in the regulation of immune responses. The past year has seen considerable progress in the identification of intracellular molecules mediating CD40 signaling. Furthermore, it has been established that ligation of CD40 ligand (CD40L) delivers signals to the CD40L bearing cells themselves. Finally, the critical role of CD40-CD40L interactions in the development of various disease states has been fully appreciated.
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Affiliation(s)
- C van Kooten
- Department of Nephrology, Leiden University Hospital, 1-C3P, Albinusdreef 2, 2333 AA, Leiden, The Netherlands.
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49
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Banchereau J, Galibert L, Arpin C, Burdin N, Liu YJ, Garrone P. Positive and negative selection of human B lymphocytes in vitro. Ann N Y Acad Sci 1997; 815:237-45. [PMID: 9186660 DOI: 10.1111/j.1749-6632.1997.tb52065.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- J Banchereau
- Laboratory for Immunological Research, Schering-Plough, Dardilly, France
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50
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Shiono H, Fujii Y, Okumura M, Takeuchi Y, Inoue M, Matsuda H. Failure to down-regulate Bcl-2 protein in thymic germinal center B cells in myasthenia gravis. Eur J Immunol 1997; 27:805-9. [PMID: 9130628 DOI: 10.1002/eji.1830270402] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The most unusual characteristic of myasthenia gravis (MG) is that the thymus has germinal centers (GC). Cultured thymic lymphocytes from MG patients spontaneously produce anti-acetylcholine receptor antibodies, indicating that autoreactive B cells have escaped negative selection. To investigate the underlying mechanism, we examined the expression of the apoptosis-related protein Bcl-2 in GC B cells (defined as CD19+ CD38+ cells) in the thymus in 14 MG patients using three-color flow cytometry. GC in MG patients did not show the normal down-regulation of Bcl-2 (the frequency of Bcl-2+ GC B cells in the MG thymus and in control tonsils 54.3 +/- 16.2% versus 20.6 +/- 8.0%; mean +/- SD. p < 0.0001). In contrast, Bcl-2 in GC in the mediastinal lymph nodes from four patients was down-regulated to a relatively normal level. Using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method to detect DNA fragmentation in situ, the frequency of TUNEL+ cells in GC in the MG thymus was lower than in control tonsils. These results suggest that autoreactive B cells which normally undergo apoptosis in GC may survive because of Bcl-2 up-regulation in this unusual location.
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Affiliation(s)
- H Shiono
- First Department of Surgery, Osaka University Medical School, Japan.
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