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Bogers L, Rip J, Rijvers L, van Langelaar J, Koetzier SC, Kuiper KL, Meerdink V, Wierenga-Wolf AF, Melief MJ, Marques AM, Smolders J, van Luijn MM. Impact of coding risk variant IFNGR2 on the B cell-intrinsic IFN-γ signaling pathway in multiple sclerosis. J Autoimmun 2024; 148:103279. [PMID: 38972102 DOI: 10.1016/j.jaut.2024.103279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 06/17/2024] [Accepted: 06/27/2024] [Indexed: 07/09/2024]
Abstract
B cells of people with multiple sclerosis (MS) are more responsive to IFN-γ, corresponding to their brain-homing potential. We studied how a coding single nucleotide polymorphism (SNP) in IFNGR2 (rs9808753) co-operates with Epstein-Barr virus (EBV) infection as MS risk factors to affect the IFN-γ signaling pathway in human B cells. In both cell lines and primary cells, EBV infection positively associated with IFN-γ receptor expression and STAT1 phosphorylation. The IFNGR2 risk SNP selectively promoted downstream signaling via STAT1, particularly in transitional B cells. Altogether, EBV and the IFNGR2 risk SNP independently amplify IFN-γ signaling, potentially driving B cells to enter the MS brain.
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Affiliation(s)
- Laurens Bogers
- Department of Immunology, MS Center ErasMS, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Jasper Rip
- Department of Immunology, MS Center ErasMS, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Liza Rijvers
- Department of Immunology, MS Center ErasMS, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Jamie van Langelaar
- Department of Immunology, MS Center ErasMS, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Steven C Koetzier
- Department of Immunology, MS Center ErasMS, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Kirsten L Kuiper
- Department of Immunology, MS Center ErasMS, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Veronique Meerdink
- Department of Immunology, MS Center ErasMS, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Annet F Wierenga-Wolf
- Department of Immunology, MS Center ErasMS, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Marie-José Melief
- Department of Immunology, MS Center ErasMS, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Ana M Marques
- Department of Immunology, MS Center ErasMS, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Joost Smolders
- Department of Immunology, MS Center ErasMS, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; Department of Neurology, MS Center ErasMS, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; Neuroimmunology Research Group, Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
| | - Marvin M van Luijn
- Department of Immunology, MS Center ErasMS, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands.
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2
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Gill RF, Mathieu PA, Lash LH, Rosenspire AJ. Naturally occurring autoimmune disease in (NZB X NZW) F1 mice is correlated with suppression of MZ B cell development due to aberrant B Cell Receptor (BCR) signaling, which is exacerbated by exposure to inorganic mercury. Toxicol Sci 2023; 197:kfad120. [PMID: 37952249 PMCID: PMC10823778 DOI: 10.1093/toxsci/kfad120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023] Open
Abstract
Autoimmune diseases are multifactorial and include environmental as well as genetic drivers. Although much progress has been made in understanding the nature of genetic underpinnings of autoimmune disease, by comparison much less is understood regarding how environmental factors interact with genetics in the development of autoimmunity and autoimmune disease. In this report, we utilize the (NZB X NZW) F1 mouse model of Systemic Lupus Erythematosus (SLE). Mercury is a xenobiotic that is environmentally ubiquitous and is epidemiologically linked with the development of autoimmunity. Among other attributes of human SLE, (NZB X NZW) F1 mice spontaneously develop autoimmune-mediated kidney disease. It has been previously shown that if (NZB X NZW) F1 mice are exposed to inorganic mercury (Hg2+), the development of autoimmunity, including autoimmune kidney pathology, is accelerated. We now show that in these mice the development of kidney disease is correlated with a decreased percentage of marginal zone (MZ) B cells in the spleen. In Hg2+-intoxicated mice, kidney disease is significantly augmented, and matched by a greater decrease in MZ B cell splenic percentages than found in control mice. In Hg2+- intoxicated mice, the decrease in MZ B cells appears to be linked to aberrant B Cell Receptor (BCR) signal strength in transitory 2 (T2) B cells, developmental precursors of MZ B cells.
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Affiliation(s)
- Randall F Gill
- Department of Biochemistry, Microbiology and Immunology, Wayne State University, Detroit, Michigan 48201, USA
| | - Patricia A Mathieu
- Department of Pharmacology, Wayne State University, Detroit, Michigan 48201, USA
| | - Lawrence H Lash
- Department of Pharmacology, Wayne State University, Detroit, Michigan 48201, USA
| | - Allen J Rosenspire
- Department of Biochemistry, Microbiology and Immunology, Wayne State University, Detroit, Michigan 48201, USA
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3
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Lee J, Robinson ME, Sun R, Kume K, Ma N, Cosgun KN, Chan LN, Leveille E, Geng H, Vykunta VS, Shy BR, Marson A, Katz S, Chen J, Paietta E, Meffre E, Vaidehi N, Müschen M. Dynamic phosphatase-recruitment controls B-cell selection and oncogenic signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.13.532151. [PMID: 36993276 PMCID: PMC10054997 DOI: 10.1101/2023.03.13.532151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Initiation of B-cell receptor (BCR) 1 signaling, and subsequent antigen-encounter in germinal centers 2,3 represent milestones of B-lymphocyte development that are both marked by sharp increases of CD25 surface-expression. Oncogenic signaling in B-cell leukemia (B-ALL) 4 and lymphoma 5 also induced CD25-surface expression. While CD25 is known as an IL2-receptor chain on T- and NK-cells 6-9 , the significance of its expression on B-cells was unclear. Our experiments based on genetic mouse models and engineered patient-derived xenografts revealed that, rather than functioning as an IL2-receptor chain, CD25 expressed on B-cells assembled an inhibitory complex including PKCδ and SHIP1 and SHP1 phosphatases for feedback control of BCR-signaling or its oncogenic mimics. Recapitulating phenotypes of genetic ablation of PKCδ 10 - 12 , SHIP1 13,14 and SHP1 14, 15,16 , conditional CD25-deletion decimated early B-cell subsets but expanded mature B-cell populations and induced autoimmunity. In B-cell malignancies arising from early (B-ALL) and late (lymphoma) stages of B-cell development, CD25-loss induced cell death in the former and accelerated proliferation in the latter. Clinical outcome annotations mirrored opposite effects of CD25-deletion: high CD25 expression levels predicted poor clinical outcomes for patients with B-ALL, in contrast to favorable outcomes for lymphoma-patients. Biochemical and interactome studies revealed a critical role of CD25 in BCR-feedback regulation: BCR-signaling induced PKCδ-mediated phosphorylation of CD25 on its cytoplasmic tail (S 268 ). Genetic rescue experiments identified CD25-S 268 tail-phosphorylation as central structural requirement to recruit SHIP1 and SHP1 phosphatases to curb BCR-signaling. A single point mutation CD25 S268A abolished recruitment and activation of SHIP1 and SHP1 to limit duration and strength of BCR-signaling. Loss of phosphatase-function, autonomous BCR-signaling and Ca 2+ -oscillations induced anergy and negative selection during early B-cell development, as opposed to excessive proliferation and autoantibody production in mature B-cells. These findings highlight the previously unrecognized role of CD25 in assembling inhibitory phosphatases to control oncogenic signaling in B-cell malignancies and negative selection to prevent autoimmune disease.
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4
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An Update on the Evolutionary History of Bregs. Genes (Basel) 2022; 13:genes13050890. [PMID: 35627275 PMCID: PMC9141580 DOI: 10.3390/genes13050890] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/07/2022] [Accepted: 05/12/2022] [Indexed: 12/22/2022] Open
Abstract
The relationship between the evolutionary history and the differentiation of Bregs is still not clear. Bregs were demonstrated to possess a regulatory effect on B cells. Various subsets of Bregs have been identified including T2-MZP, MZ, B10, IL10-producing plasma cells, IL10 producing plasmablasts, immature IL10 producing B cells, TIM1, and Br1. It is known that B cells have evolved during fish emergence. However, the origin of Bregs is still not known. Three main models have been previously proposed to describe the origin of Bregs, the first known as single–single (SS) suggests that each type of Bregs subpopulation has emerged from a single pre-Breg type. The second model (single–multi) (SM) assumes that a single Bregs gave rise to multiple types of Bregs that in turn differentiated to other Breg subpopulations. In the third model (multi–multi) (MM), it is hypothesized that Bregs arise from the nearest B cell phenotype. The link between the differentiation of cells and the evolution of novel types of cells is known to follow one of three evolutionary patterns (i.e., homology, convergence, or concerted evolution). Another aspect that controls differentiation and evolution processes is the principle of optimization of energy, which suggests that an organism will always use the choice that requires less energy expenditure for survival. In this review, we investigate the evolution of Breg subsets. We studied the feasibility of Breg origination models based on evolution and energy constraints. In conclusion, our review indicates that Bregs are likely to have evolved under a combination of SM–MM models. This combination ensured successful survival in harsh conditions by following the least costly differentiation pathway, as well as adapting to changing environmental conditions.
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5
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Unraveling B cell trajectories at single cell resolution. Trends Immunol 2022; 43:210-229. [DOI: 10.1016/j.it.2022.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/03/2022] [Accepted: 01/04/2022] [Indexed: 12/31/2022]
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6
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Podstawka J, Sinha S, Hiroki CH, Sarden N, Granton E, Labit E, Kim JH, Andonegui G, Lou Y, Snarr BD, Sheppard DC, Rosin NL, Biernaskie J, Yipp BG. Marginating transitional B cells modulate neutrophils in the lung during inflammation and pneumonia. J Exp Med 2021; 218:e20210409. [PMID: 34313733 PMCID: PMC8318832 DOI: 10.1084/jem.20210409] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 06/04/2021] [Accepted: 07/06/2021] [Indexed: 12/25/2022] Open
Abstract
Pulmonary innate immunity is required for host defense; however, excessive neutrophil inflammation can cause life-threatening acute lung injury. B lymphocytes can be regulatory, yet little is known about peripheral transitional IgM+ B cells in terms of regulatory properties. Using single-cell RNA sequencing, we discovered eight IgM+ B cell subsets with unique gene regulatory networks in the lung circulation dominated by transitional type 1 B and type 2 B (T2B) cells. Lung intravital confocal microscopy revealed that T2B cells marginate in the pulmonary capillaries via CD49e and require CXCL13 and CXCR5. During lung inflammation, marginated T2B cells dampened excessive neutrophil vascular inflammation via the specialized proresolving molecule lipoxin A4 (LXA4). Exogenous CXCL13 dampened excessive neutrophilic inflammation by increasing marginated B cells, and LXA4 recapitulated neutrophil regulation in B cell-deficient mice during inflammation and fungal pneumonia. Thus, the lung microvasculature is enriched in multiple IgM+ B cell subsets with marginating capillary T2B cells that dampen neutrophil responses.
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Affiliation(s)
- John Podstawka
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sarthak Sinha
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Carlos H. Hiroki
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Nicole Sarden
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Elise Granton
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Elodie Labit
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jung Hwan Kim
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Graciela Andonegui
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Yuefei Lou
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Brendan D. Snarr
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Donald C. Sheppard
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Division of Infectious Diseases, McGill University Health Centre, Montreal, Quebec, Canada
- Department of Medical Microbiology, McGill University Health Centre, Montreal, Quebec, Canada
| | - Nicole L. Rosin
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jeff Biernaskie
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Surgery, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Bryan G. Yipp
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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7
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Ben Nasr M, Usuelli V, Seelam AJ, D'Addio F, Abdi R, Markmann JF, Fiorina P. Regulatory B Cells in Autoimmune Diabetes. THE JOURNAL OF IMMUNOLOGY 2021; 206:1117-1125. [PMID: 33685919 DOI: 10.4049/jimmunol.2001127] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/11/2020] [Indexed: 12/24/2022]
Abstract
Since they were discovered almost three decades ago, a subset of B cells denoted as regulatory B cells (Bregs) have elicited interest throughout the immunology community. Many investigators have sought to characterize their phenotype and to understand their function and immunosuppressive mechanisms. Indeed, studies in murine models have demonstrated that Bregs possess varied phenotypic markers and could be classified into different subsets whose action and pivotal role depend on the pathological condition or stimuli. Similar conclusions were drawn in clinical settings delineating an analogous Breg population phenotypically resembling the murine Bregs that ultimately may be associated with a state of tolerance. Recent studies suggested that Bregs may play a role in the onset of autoimmune diabetes. This review will focus on deciphering the different subclasses of Bregs, their emerging role in autoimmune diabetes, and their potential use as a cell-based therapeutic.
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Affiliation(s)
- Moufida Ben Nasr
- Nephrology Division, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115.,International Center for T1D, Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Science "L. Sacco," University of Milan, 20157 Milan, Italy.,Transplantation Research Center, Nephrology Division, Children's Hospital and Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Vera Usuelli
- International Center for T1D, Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Science "L. Sacco," University of Milan, 20157 Milan, Italy
| | - Andy Joe Seelam
- International Center for T1D, Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Science "L. Sacco," University of Milan, 20157 Milan, Italy
| | - Francesca D'Addio
- International Center for T1D, Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Science "L. Sacco," University of Milan, 20157 Milan, Italy
| | - Reza Abdi
- Transplantation Research Center, Nephrology Division, Children's Hospital and Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - James F Markmann
- Center for Transplantation Sciences, Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114; and
| | - Paolo Fiorina
- Nephrology Division, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115; .,International Center for T1D, Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Science "L. Sacco," University of Milan, 20157 Milan, Italy.,Division of Endocrinology, ASST Fatebenefratelli Sacco, 20157 Milan, Italy
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8
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Acharya M, Raso F, Sagadiev S, Gilbertson E, Kadavy L, Li QZ, Yan M, Stuart LM, Hamerman JA, Lacy-Hulbert A. B Cell αv Integrins Regulate TLR-Driven Autoimmunity. THE JOURNAL OF IMMUNOLOGY 2020; 205:1810-1818. [PMID: 32859730 DOI: 10.4049/jimmunol.1901056] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 07/30/2020] [Indexed: 12/14/2022]
Abstract
Systemic lupus erythematosus (SLE) is defined by loss of B cell tolerance, resulting in production of autoantibodies against nucleic acids and other cellular Ags. Aberrant activation of TLRs by self-derived RNA and DNA is strongly associated with SLE in patients and in mouse models, but the mechanism by which TLR signaling to self-ligands is regulated remains poorly understood. In this study, we show that αv integrin plays a critical role in regulating B cell TLR signaling to self-antigens in mice. We show that deletion of αv from B cells accelerates autoantibody production and autoimmune kidney disease in the Tlr7.1 transgenic mouse model of SLE. Increased autoimmunity was associated with specific expansion of transitional B cells, extrafollicular IgG2c-producing plasma cells, and activation of CD4 and CD8 T cells. Our data show that αv-mediated regulation of TLR signaling in B cells is critical for preventing autoimmunity and indicate that loss of αv promotes escape from tolerance. Thus, we identify a new regulatory pathway in autoimmunity and elucidate upstream signals that adjust B cell activation to prevent development of autoimmunity in a mouse model.
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Affiliation(s)
- Mridu Acharya
- Immunology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA 98101; .,Seattle Children's Research Institute, Seattle, WA 98101
| | - Fiona Raso
- Immunology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA 98101
| | - Sara Sagadiev
- Immunology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA 98101.,Seattle Children's Research Institute, Seattle, WA 98101
| | - Emily Gilbertson
- Immunology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA 98101
| | - Lauren Kadavy
- Immunology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA 98101
| | - Quan Z Li
- Department of Immunology and Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Mei Yan
- Department of Immunology and Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Lynda M Stuart
- Immunology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA 98101.,Bill and Melinda Gates Foundation, Seattle, WA 98109; and
| | - Jessica A Hamerman
- Immunology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA 98101.,Department of Immunology, University of Washington, Seattle, WA 98109
| | - Adam Lacy-Hulbert
- Immunology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA 98101; .,Department of Immunology, University of Washington, Seattle, WA 98109
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9
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Raybuck AL, Lee K, Cho SH, Li J, Thomas JW, Boothby MR. mTORC1 as a cell-intrinsic rheostat that shapes development, preimmune repertoire, and function of B lymphocytes. FASEB J 2019; 33:13202-13215. [PMID: 31533002 PMCID: PMC6894075 DOI: 10.1096/fj.201900069r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 08/19/2019] [Indexed: 11/11/2022]
Abstract
Ample evidence indicates that nutrient concentrations in extracellular milieux affect signaling mediated by environmental sensor proteins. For instance, the mechanistic target of rapamycin (mTOR) is reduced during protein malnutrition and is known to be modulated by concentrations of several amino acids when in a multiprotein signaling complex that contains regulatory-associated protein of mTOR. We hypothesized that a partial decrease in mTOR complex 1 (mTORC1) activity intrinsic to B-lineage cells would perturb lymphocyte development or function, or both. We show that a cell-intrinsic decrease in mTORC1 activity impacted developmental progression, antigen receptor repertoire, and function along the B lineage. Thus, preimmune repertoires of B-lineage cells were altered in the marrow and periphery in a genetic model of regulatory-associated protein of mTOR haplo-insufficiency. An additional role for mTORC1 was revealed when a B-cell antigen receptor transgene was found to circumvent the abnormal B-cell development: haploinsufficient B cells were profoundly impaired in responses to antigen in vivo. Collectively, our findings indicate that mTORC1 serves as a rheostat that shapes differentiation along the B lineage, the preimmune repertoire, and antigen-driven selection of mature B cells. The findings also reveal a range in the impact of this nutrient sensor on activity-response relationships for distinct endpoints.-Raybuck, A. L., Lee, K., Cho, S. H., Li, J., Thomas, J. W., Boothby, M. R. mTORC1 as a cell-intrinsic rheostat that shapes development, preimmune repertoire, and function of B lymphocytes.
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Affiliation(s)
- Ariel L. Raybuck
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Keunwook Lee
- Department of Biomedical Science, Hallym University, Chuncheon, Gangwon-do, South Korea
| | - Sung Hoon Cho
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation (VI4), Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jingxin Li
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - James W. Thomas
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Mark R. Boothby
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation (VI4), Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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10
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Boldison J, Da Rosa LC, Buckingham L, Davies J, Wen L, Wong FS. Phenotypically distinct anti-insulin B cells repopulate pancreatic islets after anti-CD20 treatment in NOD mice. Diabetologia 2019; 62:2052-2065. [PMID: 31444529 PMCID: PMC6805803 DOI: 10.1007/s00125-019-04974-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 07/08/2019] [Indexed: 01/10/2023]
Abstract
AIMS/HYPOTHESIS Autoreactive B cells escape immune tolerance and contribute to the pathogenesis of type 1 diabetes. While global B cell depletion is a successful therapy for autoimmune disease, the fate of autoreactive cells during this treatment in autoimmune diabetes is unknown. We aimed to identify and track anti-insulin B cells in pancreatic islets and understand their repopulation after anti-CD20 treatment. METHODS We generated a double transgenic system, the VH125.hCD20/NOD mouse. The VH125 transgenic mouse, expressing an increased frequency of anti-insulin B cells, was crossed with a human CD20 (hCD20) transgenic mouse, to facilitate B cell depletion using anti-CD20. B cells were analysed using multiparameter and ImageStream flow cytometry. RESULTS We demonstrated that anti-insulin B cells were recruited to the pancreas during disease progression in VH125.hCD20/NOD mice. We identified two distinct populations of anti-insulin B cells in pancreatic islets, based on CD19 expression, with both populations enriched in the CD138int fraction. Anti-insulin B cells were not identified in the plasma-cell CD138hi fraction, which also expressed the transcription factor Blimp-1. After anti-CD20 treatment, anti-insulin B cells repopulated the pancreatic islets earlier than non-specific B cells. Importantly, we observed that a CD138intinsulin+CD19- population was particularly enriched after B cell depletion, possibly contributing to the persistence of disease still observed in some mice after anti-CD20 treatment. CONCLUSIONS/INTERPRETATION Our observations may indicate why the loss of C-peptide is only temporarily delayed following anti-CD20 treatment in human type 1 diabetes.
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Affiliation(s)
- Joanne Boldison
- Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, CF14 4XN, UK
| | - Larissa C Da Rosa
- Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, CF14 4XN, UK
| | - Lucy Buckingham
- Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, CF14 4XN, UK
| | - Joanne Davies
- Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, CF14 4XN, UK
| | - Li Wen
- Section of Endocrinology, School of Medicine, Yale University, New Haven, CT, USA
| | - F Susan Wong
- Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, CF14 4XN, UK.
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11
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Wąsik M, Nazimek K, Bryniarski K. Regulatory B cell phenotype and mechanism of action: the impact of stimulating conditions. Microbiol Immunol 2018; 62:485-496. [PMID: 29998521 DOI: 10.1111/1348-0421.12636] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 06/29/2018] [Accepted: 07/09/2018] [Indexed: 12/14/2022]
Abstract
A diverse population of regulatory B (Breg) cells reportedly exhibits significant immunomodulatory effects in various models of inflammatory responses and infectious diseases caused by bacteria, viruses or parasites. Breg cells contribute to maintenance of homeostasis via IL-10 production and multiple IL-10-independent mechanisms. The current review describes various phenotypic and functional subsets of Breg cells in autoimmune and infectious diseases and discusses the impacts of experimental conditions that have been found to drive Breg cell differentiation.
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Affiliation(s)
- Magdalena Wąsik
- Department of Immunology, Jagiellonian University College of Medicine, 18 Czysta St., 31-121 Krakow, Poland
| | - Katarzyna Nazimek
- Department of Immunology, Jagiellonian University College of Medicine, 18 Czysta St., 31-121 Krakow, Poland
| | - Krzysztof Bryniarski
- Department of Immunology, Jagiellonian University College of Medicine, 18 Czysta St., 31-121 Krakow, Poland
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12
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Hwang IY, Boularan C, Harrison K, Kehrl JH. Gα i Signaling Promotes Marginal Zone B Cell Development by Enabling Transitional B Cell ADAM10 Expression. Front Immunol 2018; 9:687. [PMID: 29696016 PMCID: PMC5904254 DOI: 10.3389/fimmu.2018.00687] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 03/20/2018] [Indexed: 12/15/2022] Open
Abstract
The follicular (FO) versus marginal zone (MZ) B cell fate decision in the spleen depends upon BCR, BAFF, and Notch2 signaling. Whether or how Gi signaling affects this fate decision is unknown. Here, we show that direct contact with Notch ligand expressing stromal cells (OP9-Delta-like 1) cannot promote normal MZ B cell development when progenitor B cells lack Gαi proteins, or if Gi signaling is disabled. Consistent with faulty ADAM10-dependent Notch2 processing, Gαi-deficient transitional B cells had low ADAM10 membrane expression levels and reduced Notch2 target gene expression. Immunoblotting Gαi-deficient B cell lysates revealed a reduction in mature, processed ADAM10. Suggesting that Gαi signaling promotes ADAM10 membrane expression, stimulating normal transitional B cells with CXCL12 raised it, while inhibiting Gαi nucleotide exchange blocked its upregulation. Surprisingly, inhibiting Gαi nucleotide exchange in transitional B cells also impaired the upregulation of ADAM10 that occurs following antigen receptor crosslinking. These results indicate that Gαi signaling supports ADAM10 maturation and activity in transitional B cells, and ultimately Notch2 signaling to promote MZ B cell development.
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Affiliation(s)
- Il-Young Hwang
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Cedric Boularan
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States.,InvivoGen, Toulouse, France
| | - Kathleen Harrison
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - John H Kehrl
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
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Bocian K, Kiernozek E, Domagała-Kulawik J, Korczak-Kowalska G, Stelmaszczyk-Emmel A, Drela N. Expanding Diversity and Common Goal of Regulatory T and B Cells. I: Origin, Phenotype, Mechanisms. Arch Immunol Ther Exp (Warsz) 2017; 65:501-520. [PMID: 28477096 PMCID: PMC5688216 DOI: 10.1007/s00005-017-0469-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 03/14/2017] [Indexed: 12/21/2022]
Abstract
Immunosuppressive activity of regulatory T and B cells is critical to limit autoimmunity, excessive inflammation, and pathological immune response to conventional antigens or allergens. Both types of regulatory cells are intensively investigated, however, their development and mechanisms of action are still not completely understood. Both T and B regulatory cells represent highly differentiated populations in terms of phenotypes and origin, however, they use similar mechanisms of action. The most investigated CD4+CD25+ regulatory T cells are characterized by the expression of Foxp3+ transcription factor, which is not sufficient to maintain their lineage stability and suppressive function. Currently, it is considered that specific epigenetic changes are critical for defining regulatory T cell stability in the context of their suppressive function. It is not yet known if similar epigenetic regulation determines development, lineage stability, and function of regulatory B cells. Phenotype diversity, confirmed or hypothetical developmental pathways, multiple mechanisms of action, and role of epigenetic changes in these processes are the subject of this review.
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Affiliation(s)
- Katarzyna Bocian
- Department of Immunology, Faculty of Biology, University of Warsaw, Warsaw, Poland.
| | - Ewelina Kiernozek
- Department of Immunology, Faculty of Biology, University of Warsaw, Warsaw, Poland.
| | | | - Grażyna Korczak-Kowalska
- Department of Immunology, Faculty of Biology, University of Warsaw, Warsaw, Poland
- Department of Clinical Immunology, Transplantation Institute, Medical University of Warsaw, Warsaw, Poland
| | - Anna Stelmaszczyk-Emmel
- Department of Laboratory Diagnostics and Clinical Immunology of Developmental Age, Medical University of Warsaw, Warsaw, Poland
| | - Nadzieja Drela
- Department of Immunology, Faculty of Biology, University of Warsaw, Warsaw, Poland
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14
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Myers DR, Zikherman J, Roose JP. Tonic Signals: Why Do Lymphocytes Bother? Trends Immunol 2017; 38:844-857. [PMID: 28754596 DOI: 10.1016/j.it.2017.06.010] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 06/23/2017] [Accepted: 06/27/2017] [Indexed: 01/09/2023]
Abstract
Since the 1990s it has been known that B and T lymphocytes exhibit low-level, constitutive signaling in the basal state (tonic signaling). These lymphocytes display a range of affinity for self, which in turn generates a range of tonic signaling. Surprisingly, what signaling pathways are active in the basal state and the functional relevance of the observed tonic signaling heterogeneity remain open questions today. Here we summarize what is known about the mechanistic and functional details of tonic signaling. We highlight recent advances that have increased our understanding of how the amount of tonic signal impacts immune function, describing novel tools that have moved the field forward and toward a molecular understanding of tonic signaling.
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Affiliation(s)
- Darienne R Myers
- Department of Anatomy, School of Medicine, University of California, San Francisco, CA 94143, USA
| | - Julie Zikherman
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, CA 94143, USA
| | - Jeroen P Roose
- Department of Anatomy, School of Medicine, University of California, San Francisco, CA 94143, USA.
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15
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Hemon P, Renaudineau Y, Debant M, Le Goux N, Mukherjee S, Brooks W, Mignen O. Calcium Signaling: From Normal B Cell Development to Tolerance Breakdown and Autoimmunity. Clin Rev Allergy Immunol 2017; 53:141-165. [DOI: 10.1007/s12016-017-8607-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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16
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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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17
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von Wnuck Lipinski K, Sattler K, Peters S, Weske S, Keul P, Klump H, Heusch G, Göthert JR, Levkau B. Hepatocyte Nuclear Factor 1A Is a Cell-Intrinsic Transcription Factor Required for B Cell Differentiation and Development in Mice. THE JOURNAL OF IMMUNOLOGY 2016; 196:1655-65. [PMID: 26800876 DOI: 10.4049/jimmunol.1500897] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 12/07/2015] [Indexed: 12/22/2022]
Abstract
The hepatocyte NF (HNF) family of transcription factors regulates the complex gene networks involved in lipid, carbohydrate, and protein metabolism. In humans, HNF1A mutations cause maturity onset of diabetes in the young type 3, whereas murine HNF6 participates in fetal liver B lymphopoiesis. In this study, we have identified a crucial role for the prototypical member of the family HNF1A in adult bone marrow B lymphopoiesis. HNF1A(-/-) mice exhibited a clear reduction in total blood and splenic B cells and a further pronounced one in transitional B cells. In HNF1A(-/-) bone marrow, all B cell progenitors-from pre-pro-/early pro-B cells to immature B cells-were dramatically reduced and their proliferation rate suppressed. IL-7 administration in vivo failed to boost B cell development in HNF1A(-/-) mice, whereas IL-7 stimulation of HNF1A(-/-) B cell progenitors in vitro revealed a marked impairment in STAT5 phosphorylation. The B cell differentiation potential of HNF1A(-/-) common lymphoid progenitors was severely impaired in vitro, and the expression of the B lymphopoiesis-promoting transcription factors E2A, EBF1, Pax5, and Bach2 was reduced in B cell progenitors in vivo. HNF1A(-/-) bone marrow chimera featured a dramatic defect in B lymphopoiesis recapitulating that of global HNF1A deficiency. The HNF1A(-/-) lymphopoiesis defect was confined to B cells as T lymphopoiesis was unaffected, and bone marrow common lymphoid progenitors and hematopoietic stem cells were even increased. Our data demonstrate that HNF1A is an important cell-intrinsic transcription factor in adult B lymphopoiesis and suggest the IL-7R/STAT5 module to be causally involved in mediating its function.
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Affiliation(s)
- Karin von Wnuck Lipinski
- Institute for Pathophysiology, West German Heart and Vascular Center, University Hospital Essen, 45122 Essen, Germany
| | - Katherine Sattler
- Institute for Pathophysiology, West German Heart and Vascular Center, University Hospital Essen, 45122 Essen, Germany
| | - Susann Peters
- Institute for Pathophysiology, West German Heart and Vascular Center, University Hospital Essen, 45122 Essen, Germany
| | - Sarah Weske
- Institute for Pathophysiology, West German Heart and Vascular Center, University Hospital Essen, 45122 Essen, Germany
| | - Petra Keul
- Institute for Pathophysiology, West German Heart and Vascular Center, University Hospital Essen, 45122 Essen, Germany
| | - Hannes Klump
- Institute for Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany; and
| | - Gerd Heusch
- Institute for Pathophysiology, West German Heart and Vascular Center, University Hospital Essen, 45122 Essen, Germany
| | - Joachim R Göthert
- Department of Hematology, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany
| | - Bodo Levkau
- Institute for Pathophysiology, West German Heart and Vascular Center, University Hospital Essen, 45122 Essen, Germany;
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18
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Sharifi L, Mirshafiey A, Rezaei N, Azizi G, Magaji Hamid K, Amirzargar AA, Asgardoon MH, Aghamohammadi A. The role of toll-like receptors in B-cell development and immunopathogenesis of common variable immunodeficiency. Expert Rev Clin Immunol 2015; 12:195-207. [PMID: 26654573 DOI: 10.1586/1744666x.2016.1114885] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Common variable immunodeficiency (CVID) is the most frequent symptomatic primary immune deficiency and is characterized by hypogammaglobulinemia, defect in specific antibody response and increased susceptibility to recurrent infections, malignancy and autoimmunity. Patients with CVID often have defects in post-antigenic B-cell differentiation, with fewer memory B cells and impaired isotype switching. Toll-like receptors (TLRs) are expressed on various immune cells as key elements of innate and adaptive immunity. TLR signaling in B cells plays multiple roles in cell differentiation and activation, class-switch recombination and cytokine and antibody production. Moreover, recent studies have shown functional alteration of TLRs responses in CVID patients including poor cell proliferation, impaired upregulation of co-stimulatory molecules and failure in cytokine and immunoglobulin production. The purpose of the present review is to discuss the role of TLRs in B-cell development and function as well as their role in the immunopathogenesis of CVID.
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Affiliation(s)
- Laleh Sharifi
- a Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center , Tehran University of Medical Sciences , Tehran , Iran
| | - Abbas Mirshafiey
- a Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center , Tehran University of Medical Sciences , Tehran , Iran.,b Department of Immunology, School of Public Health , Tehran University of Medical Sciences , Tehran , Iran
| | - Nima Rezaei
- a Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center , Tehran University of Medical Sciences , Tehran , Iran.,c Department of Immunology, School of Medicine , Tehran University of Medical Sciences , Tehran , Iran
| | - Gholamreza Azizi
- d Imam Hassan Mojtaba Hospital , Alborz University of Medical Sciences , Karaj , Iran
| | - Kabir Magaji Hamid
- b Department of Immunology, School of Public Health , Tehran University of Medical Sciences , Tehran , Iran.,e Immunology Department, Faculty of Medical Laboratory Sciences , Usmanu Danfodiyo University , Sokoto , Nigeria
| | - Ali Akbar Amirzargar
- c Department of Immunology, School of Medicine , Tehran University of Medical Sciences , Tehran , Iran
| | - Mohammad Hossein Asgardoon
- a Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center , Tehran University of Medical Sciences , Tehran , Iran
| | - Asghar Aghamohammadi
- a Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center , Tehran University of Medical Sciences , Tehran , Iran
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19
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Ding T, Yan F, Cao S, Ren X. Regulatory B cell: New member of immunosuppressive cell club. Hum Immunol 2015; 76:615-21. [PMID: 26385479 DOI: 10.1016/j.humimm.2015.09.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 08/17/2015] [Accepted: 09/12/2015] [Indexed: 02/07/2023]
Abstract
Historically, the pivotal role of B cells or B lymphocytes in immunity has been attributed to the production of antibodies. They were also demonstrated to present antigens to T cells and to secrete cytokines, thereby acting as positive regulators in immune responses. A series of studies on autoimmune diseases, however, led researchers to find a unique subset of B cells, later described as "regulatory B cells" (Bregs), that has the ability to suppress immune responses. Bregs occur not only in autoimmune diseases, but also in inflammation and transplantation. Furthermore, recently published literatures suggested that Bregs contributed to the growth and metastasis of certain cancers. In this review, we will discuss these unique subsets of B cells in different kinds of disorders, with particular emphasis on the mechanisms of their immunoregulatory role that were collected from mice and humans.
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Affiliation(s)
- Tingting Ding
- Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China; Department of Biotherapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China; Key Laboratory of Cancer Immunology and Biotherapy, Tianjin 300060, China; National Clinical Research Center of Cancer, China
| | - Fan Yan
- Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China; Key Laboratory of Cancer Immunology and Biotherapy, Tianjin 300060, China; National Clinical Research Center of Cancer, China
| | - Shui Cao
- Department of Biotherapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China; Key Laboratory of Cancer Immunology and Biotherapy, Tianjin 300060, China; National Clinical Research Center of Cancer, China.
| | - Xiubao Ren
- Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China; Department of Biotherapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China; Key Laboratory of Cancer Immunology and Biotherapy, Tianjin 300060, China; National Clinical Research Center of Cancer, China.
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20
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The Role of p110δ in the Development and Activation of B Lymphocytes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 850:119-35. [DOI: 10.1007/978-3-319-15774-0_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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21
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Benitez A, Weldon AJ, Tatosyan L, Velkuru V, Lee S, Milford TA, Francis OL, Hsu S, Nazeri K, Casiano CM, Schneider R, Gonzalez J, Su RJ, Baez I, Colburn K, Moldovan I, Payne KJ. Differences in mouse and human nonmemory B cell pools. THE JOURNAL OF IMMUNOLOGY 2014; 192:4610-9. [PMID: 24719464 DOI: 10.4049/jimmunol.1300692] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Identifying cross-species similarities and differences in immune development and function is critical for maximizing the translational potential of animal models. Coexpression of CD21 and CD24 distinguishes transitional and mature B cell subsets in mice. In this study, we validate these markers for identifying analogous subsets in humans and use them to compare the nonmemory B cell pools in mice and humans, across tissues, and during fetal/neonatal and adult life. Among human CD19(+)IgM(+) B cells, the CD21/CD24 schema identifies distinct populations that correspond to transitional 1 (T1), transitional 2 (T2), follicular mature, and marginal zone subsets identified in mice. Markers specific to human B cell development validate the identity of marginal zone cells and the maturation status of human CD21/CD24 nonmemory B cell subsets. A comparison of the nonmemory B cell pools in bone marrow, blood, and spleen in mice and humans shows that transitional B cells comprise a much smaller fraction in adult humans than mice. T1 cells are a major contributor to the nonmemory B cell pool in mouse bone marrow, in which their frequency is more than twice that in humans. Conversely, in spleen, the T1:T2 ratio shows that T2 cells are proportionally ∼ 8-fold higher in humans than in mice. Despite the relatively small contribution of transitional B cells to the human nonmemory pool, the number of naive follicular mature cells produced per transitional B cell is 3- to 6-fold higher across tissues than in mice. These data suggest differing dynamics or mechanisms produce the nonmemory B cell compartments in mice and humans.
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Affiliation(s)
- Abigail Benitez
- Department of Basic Sciences, Loma Linda University, Loma Linda, CA 92350
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22
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Mice with megabase humanization of their immunoglobulin genes generate antibodies as efficiently as normal mice. Proc Natl Acad Sci U S A 2014; 111:5153-8. [PMID: 24706856 DOI: 10.1073/pnas.1324022111] [Citation(s) in RCA: 314] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Mice genetically engineered to be humanized for their Ig genes allow for human antibody responses within a mouse background (HumAb mice), providing a valuable platform for the generation of fully human therapeutic antibodies. Unfortunately, existing HumAb mice do not have fully functional immune systems, perhaps because of the manner in which their genetic humanization was carried out. Heretofore, HumAb mice have been generated by disrupting the endogenous mouse Ig genes and simultaneously introducing human Ig transgenes at a different and random location; KO-plus-transgenic humanization. As we describe in the companion paper, we attempted to make mice that more efficiently use human variable region segments in their humoral responses by precisely replacing 6 Mb of mouse Ig heavy and kappa light variable region germ-line gene segments with their human counterparts while leaving the mouse constant regions intact, using a unique in situ humanization approach. We reasoned the introduced human variable region gene segments would function indistinguishably in their new genetic location, whereas the retained mouse constant regions would allow for optimal interactions and selection of the resulting antibodies within the mouse environment. We show that these mice, termed VelocImmune mice because they were generated using VelociGene technology, efficiently produce human:mouse hybrid antibodies (that are rapidly convertible to fully human antibodies) and have fully functional humoral immune systems indistinguishable from those of WT mice. The efficiency of the VelocImmune approach is confirmed by the rapid progression of 10 different fully human antibodies into human clinical trials.
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23
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Protein kinase Cδ promotes transitional B cell-negative selection and limits proximal B cell receptor signaling to enforce tolerance. Mol Cell Biol 2014; 34:1474-85. [PMID: 24515435 DOI: 10.1128/mcb.01699-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Protein kinase Cδ (PKCδ) deficiency causes autoimmune pathology in humans and mice and is crucial for the maintenance of B cell homeostasis. However, the mechanisms underlying autoimmune disease in PKCδ deficiency remain poorly defined. Here, we address the antigen-dependent and -independent roles of PKCδ in B cell development, repertoire selection, and antigen responsiveness. We demonstrate that PKCδ is rapidly phosphorylated downstream of both the B cell receptor (BCR) and the B cell-activating factor (BAFF) receptor. We found that PKCδ is essential for antigen-dependent negative selection of splenic transitional B cells and is required for activation of the proapoptotic Ca(2+)-Erk pathway that is selectively activated during B cell-negative selection. Unexpectedly, we also identified a previously unrecognized role for PKCδ as a proximal negative regulator of BCR signaling that substantially impacts survival and proliferation of mature follicular B cells. As a consequence of these distinct roles, PKCδ deficiency leads to the survival and development of a B cell repertoire that is not only aberrantly autoreactive but also hyperresponsive to antigen stimulation.
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24
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Khan WN, Wright JA, Kleiman E, Boucher JC, Castro I, Clark ES. B-lymphocyte tolerance and effector function in immunity and autoimmunity. Immunol Res 2013; 57:335-53. [DOI: 10.1007/s12026-013-8466-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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25
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Hepatocyte growth factor regulated tyrosine kinase substrate in the peripheral development and function of B-cells. Biochem Biophys Res Commun 2013; 443:351-6. [PMID: 24246674 DOI: 10.1016/j.bbrc.2013.11.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 11/06/2013] [Indexed: 12/24/2022]
Abstract
Hepatocyte growth factor (HGF)-regulated tyrosine kinase substrate (Hrs) is a vesicular sorting protein that functions as one of the endosomal-sorting proteins required for transport (ESCRT). Hrs, which binds to ubiquitinated proteins through its ubiquitin-interacting motif (UIM), contributes to the lysosomal transport and degradation of ubiquitinated membrane proteins. However, little is known about the relationship between B-cell functions and ESCRT proteins in vivo. Here we examined the immunological roles of Hrs in B-cell development and functions using B-cell-specific Hrs-deficient (Hrs(flox/flox);mb1(cre/)(+):Hrs-cKO) mice, which were generated using a cre-LoxP recombination system. Hrs deficiency in B-cells significantly reduced T-cell-dependent antibody production in vivo and impaired the proliferation of B-cells treated in vitro with an anti-IgM monoclonal antibody but not with LPS. Although early development of B-cells in the bone marrow was normal in Hrs-cKO mice, there was a significant decrease in the number of the peripheral transitional B-cells and marginal zone B-cells in the spleen of Hrs-cKO mice. These results indicate that Hrs plays important roles during peripheral development and physiological functions of B lymphocytes.
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26
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Abstract
Regulatory B cells (Breg) are a subpopulation of B cells that play a suppressive role in the immune system. The mechanism of how these immune cells perform their effects has been explored by experiments in mice and in humans. Intracellular staining for interleukin 10 continues to be a consistent and reproducible method of identifying Breg in mouse and human studies. The lack of Breg is associated with a worsening of several autoimmune diseases such as collagen-induced arthritis, systemic lupus erythematosus, and experimental autoimmune encephalomyelitis in murine studies. The purpose of this review is to provide a concise summary of the role of Breg in the immune system, including the most recently studied cell surface markers associated with Breg, and to describe the role of Breg in the etiology of several autoimmune diseases, the current understanding of Breg development, their role in the development of autoimmune diseases, and their role in inducing tolerance after transplantation.
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Affiliation(s)
- I Goode
- Institute for Cellular Therapeutics, University of Louisville, Louisville, Kentucky, USA
| | - H Xu
- Institute for Cellular Therapeutics, University of Louisville, Louisville, Kentucky, USA
| | - S T Ildstad
- Institute for Cellular Therapeutics, University of Louisville, Louisville, Kentucky, USA.
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27
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Giltiay NV, Chappell CP, Sun X, Kolhatkar N, Teal TH, Wiedeman AE, Kim J, Tanaka L, Buechler MB, Hamerman JA, Imanishi-Kari T, Clark EA, Elkon KB. Overexpression of TLR7 promotes cell-intrinsic expansion and autoantibody production by transitional T1 B cells. ACTA ACUST UNITED AC 2013; 210:2773-89. [PMID: 24145511 PMCID: PMC3832927 DOI: 10.1084/jem.20122798] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Transgenic expression of TLR7 results in the expansion and hyperactivation of T1 B cells in response to endogenous RNA complexes, leading to increased autoantibody production. Toll-like receptor (TLR), a ligand for single-stranded RNA, has been implicated in the development of pathogenic anti-RNA autoantibodies both in systemic lupus erythematous (SLE) patients and in murine models of lupus. It is still unclear, however, where and how TLR7-mediated interactions affect the development of autoreactive B cells. We found that overexpression of TLR7 in transgenic mice (TLR7.1Tg) leads to marked alterations of transitional (T1) B cells, associated with their expansion and proliferation within the splenic red pulp (RP). This phenotype was intrinsic to the T1 subset of B cells and occurred independently of type 1 IFN signals. Overexpression of RNase in TLR7.1Tg mice significantly limited the expansion and proliferation of T1 cells, indicating that endogenous RNA complexes are driving their activation. TLR7.1Tg T1 cells were hyper-responsive to anti-IgM and TLR7 ligand stimulation in vitro and produced high concentrations of class-switched IgG2b and IgG2c, including anti-RNA antibodies. Our results demonstrate that initial TLR7 stimulation of B cells occurs at the T1 stage of differentiation in the splenic RP and suggest that dysregulation of TLR7 expression in T1 cells can result in production of autoantibodies.
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Affiliation(s)
- Natalia V Giltiay
- Department of Immunology and 2 Division of Rheumatology, School of Medicine, University of Washington, Seattle, WA 98195
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28
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Ksionda O, Limnander A, Roose JP. RasGRP Ras guanine nucleotide exchange factors in cancer. FRONTIERS IN BIOLOGY 2013; 8:508-532. [PMID: 24744772 PMCID: PMC3987922 DOI: 10.1007/s11515-013-1276-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
RasGRP proteins are activators of Ras and other related small GTPases by the virtue of functioning as guanine nucleotide exchange factors (GEFs). In vertebrates, four RasGRP family members have been described. RasGRP-1 through -4 share many structural domains but there are also subtle differences between each of the different family members. Whereas SOS RasGEFs are ubiquitously expressed, RasGRP proteins are expressed in distinct patterns, such as in different cells of the hematopoietic system and in the brain. Most studies have concentrated on the role of RasGRP proteins in the development and function of immune cell types because of the predominant RasGRP expression profiles in these cells and the immune phenotypes of mice deficient for Rasgrp genes. However, more recent studies demonstrate that RasGRPs also play an important role in tumorigenesis. Examples are skin- and hematological-cancers but also solid malignancies such as melanoma or prostate cancer. These novel studies bring up many new and unanswered questions related to the molecular mechanism of RasGRP-driven oncogenesis, such as new receptor systems that RasGRP appears to respond to as well as regulatory mechanism for RasGRP expression that appear to be perturbed in these cancers. Here we will review some of the known aspects of RasGRP biology in lymphocytes and will discuss the exciting new notion that RasGRP Ras exchange factors play a role in oncogenesis downstream of various growth factor receptors.
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Affiliation(s)
- Olga Ksionda
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Andre Limnander
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jeroen P. Roose
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
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Stolp J, Mariño E, Batten M, Sierro F, Cox SL, Grey ST, Silveira PA. Intrinsic molecular factors cause aberrant expansion of the splenic marginal zone B cell population in nonobese diabetic mice. THE JOURNAL OF IMMUNOLOGY 2013; 191:97-109. [PMID: 23740954 DOI: 10.4049/jimmunol.1203252] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Marginal zone (MZ) B cells are an innate-like population that oscillates between MZ and follicular areas of the splenic white pulp. Differentiation of B cells into the MZ subset is governed by BCR signal strength and specificity, NF-κB activation through the B cell-activating factor belonging to the TNF family (BAFF) receptor, Notch2 signaling, and migration signals mediated by chemokine, integrin, and sphingosine-1-phosphate receptors. An imbalance in splenic B cell development resulting in expansion of the MZ subset has been associated with autoimmune pathogenesis in various murine models. One example is the NOD inbred mouse strain, in which MZ B cell expansion has been linked to development of type 1 diabetes and Sjögren's syndrome. However, the cause of MZ B cell expansion in this strain remains poorly understood. We have determined that increased MZ B cell development in NOD mice is independent of T cell autoimmunity, BCR specificity, BCR signal strength, and increased exposure to BAFF. Rather, mixed bone marrow chimeras showed that the factor(s) responsible for expansion of the NOD MZ subset is B cell intrinsic. Analysis of microarray expression data indicated that NOD MZ and precursor transitional 2-MZ subsets were particularly dysregulated for genes controlling cellular trafficking, including Apoe, Ccbp2, Cxcr7, Lgals1, Pla2g7, Rgs13, S1pr3, Spn, Bid, Cd55, Prf1, and Tlr3. Furthermore, these B cell subsets exhibited an increased steady state dwell time within splenic MZ areas. Our data therefore reveal that precursors of mature B cells in NOD mice exhibit an altered migration set point, allowing increased occupation of the MZ, a niche favoring MZ B cell differentiation.
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Affiliation(s)
- Jessica Stolp
- Garvan Institute of Medical Research, Immunology Program, Darlinghurst, New South Wales 2010, Australia
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30
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Debnath I, Roundy KM, Pioli PD, Weis JJ, Weis JH. Bone marrow-induced Mef2c deficiency delays B-cell development and alters the expression of key B-cell regulatory proteins. Int Immunol 2012; 25:99-115. [PMID: 23087187 DOI: 10.1093/intimm/dxs088] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The Mef2 family transcriptional regulator Mef2c (myocyte enhancer factor 2c) is highly expressed in maturing bone marrow and peripheral mature B-cells. To evaluate the role of this transcription factor in B-cell development, we generated a B-cell-specific conditional deletion of Mef2c using the Mb-1-Cre transgene that is expressed during the early stages of immunoglobulin rearrangement. Young mice possessing this defect demonstrated a significant impairment in B-cell numbers in bone marrow and spleen. This phenotype was evident in all B-cell subsets; however, as the animals mature, the deficit in the peripheral mature B-cell compartments was overcome. The absence of Mef2c in mature B-cells led to unique CD23+ and CD23- subsets that were evident in Mef2c knockout primary samples as well as Mef2c-deficient cultured, differentiated B-cells. Genome-wide expression analysis of immature and mature B-cells lacking Mef2c indicated altered expression for a number of key regulatory proteins for B-cell function including Ciita, CD23, Cr1/Cr2 and Tnfsf4. Chromatin immunoprecipitation analysis confirmed Mef2c binding to the promoters of these genes indicating a direct link between the presence (or absence) of Mef2c and altered transcriptional control in mature B-cells.
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Affiliation(s)
- Irina Debnath
- The Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
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31
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Zhang Z, Zhou L, Yang X, Wang Y, Zhang P, Hou L, Hu X, Xing Y, Liu Y, Li W, Han H. Notch-RBP-J-independent marginal zone B cell development in IgH transgenic mice with VH derived from a natural polyreactive antibody. PLoS One 2012; 7:e38894. [PMID: 22719978 PMCID: PMC3374804 DOI: 10.1371/journal.pone.0038894] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 05/14/2012] [Indexed: 11/18/2022] Open
Abstract
Both the B cell antigen receptor (BCR) signaling and Notch signaling pathway play important roles in marginal zone (MZ) B cell development; however, if and how these two signaling pathways engage in crosstalk with each other remain unclear. In the present study, IgH transgenic mice (TgV(H)3B4) were crossed with mice with Notch downstream transcription factor RBP-J floxed alleles (RBP-J(f/f)) and Mx-Cre transgene. Subsequently, MZ B cell development was analyzed in 3B4/Cre/RBP-J(f/f) mice that expressed the transgenic 3B4 IgH and exhibited a deficiency in Notch signaling in B cells upon poly (I:C) injection. We observed that MZ B cell numbers were severely reduced, but still detectable in 3B4/Cre/RBP-J(f/f) mice, in contrast to increased numbers of MZ B cells in TgV(H)3B4 mice and almost no MZ B cells in Cre/RBP-J(f/f) mice. The majority of the MZ B cells in the 3B4/Cre/RBP-J(f/f) mice had the same antigen specificity with that of 3B4 antibody, indicating that a particular BCR specificity might direct MZ B cell development in the absence of Notch signaling. The number of MZ B precursor (MZP) cells was reduced sharply in 3B4/Cre/RBP-J(f/f) mice, and the number of transitional stage 1 and transitional stage 2 cells did not change that much, indicating that the interaction between BCR and Notch signaling likely occurred during the T2-MZP stage. Based on the transgenic mouse model, our data indicate that MZ B cells with certain BCR specificity can develop in a Notch-RBP-J independent manner.
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Affiliation(s)
- Zhuo Zhang
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
- Department of Neurology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Lanhua Zhou
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
- Department of Dermatology, Affiliated Hospital of Institute of Aviation Medicine, Air Force, Beijing, China
| | - Xinwei Yang
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, China
| | - Yaochun Wang
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, China
| | - Ping Zhang
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, China
| | - Lihong Hou
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, China
| | - Xinbin Hu
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, China
| | - Ying Xing
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, China
| | - Yufeng Liu
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Wei Li
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, China
- * E-mail: (WL); (HH)
| | - Hua Han
- Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, China
- * E-mail: (WL); (HH)
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32
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The degree of BCR and NFAT activation predicts clinical outcomes in chronic lymphocytic leukemia. Blood 2012; 120:356-65. [PMID: 22613791 DOI: 10.1182/blood-2011-12-397158] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
B-cell antigen receptor (BCR)-mediated signaling plays a critical role in chronic lymphocytic leukemia (CLL) pathogenesis and gives an in vitro survival advantage to B cells isolated from patients with unfavorable prognostic factors. In this study, we undertook to elucidate the signaling intermediates responsible for this biologic alteration. In responding cells only, in vitro BCR engagement triggers global phosphorylation of Syk, activation of phospholipase Cγ2, and intracellular calcium mobilization, reflecting competency of BCR signaling. The calcium-calcineurin-dependent transcription factor NFAT2 is up-regulated and to some extent constitutively activated in all CLL B cells. In contrast, its DNA-binding capacity is enhanced on IgM stimulation in responding cells only. NFAT inhibition using the VIVIT peptide prevents induction of CD23 target gene and IgM-induced survival, converting responding cells to unresponsive status. At the opposite, ionomycin-induced NFAT activity allows survival of nonresponding cells. These results demonstrate that the functional heterogeneity relies on variability of protein levels establishing BCR-dependent thresholds and NFAT-dependent activation. Finally, status of the BCR-NFAT pathway for each patient reveals its relevance for CLL clinical outcome and points out to BCR-NFAT intermediates as promising functional therapeutic targets.
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Wiskott-Aldrich syndrome protein (WASP) and N-WASP are critical for peripheral B-cell development and function. Blood 2012; 119:3966-74. [PMID: 22411869 DOI: 10.1182/blood-2010-09-308197] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Wiskott-Aldrich syndrome protein (WASP) is a key cytoskeletal regulator of hematopoietic cells. Although WASP-knockout (WKO) mice have aberrant B-cell cytoskeletal responses, B-cell development is relatively normal. We hypothesized that N-WASP, a ubiquitously expressed homolog of WASP, may serve some redundant functions with WASP in B cells. In the present study, we generated mice lacking WASP and N-WASP in B cells (conditional double knockout [cDKO] B cells) and show that cDKO mice had decreased numbers of follicular and marginal zone B cells in the spleen. Receptor-induced activation of cDKO B cells led to normal proliferation but a marked reduction of spreading compared with wild-type and WKO B cells. Whereas WKO B cells showed decreased migration in vitro and homing in vivo compared with wild-type cells, cDKO B cells showed an even more pronounced decrease in the migratory response in vivo. After injection of 2,4,6-trinitrophenol (TNP)-Ficoll, cDKO B cells had reduced antigen uptake in the splenic marginal zone. Despite high basal serum IgM, cDKO mice mounted a reduced immune response to the T cell-independent antigen TNP-Ficoll and to the T cell-dependent antigen TNP-keyhole limpet hemocyanin. Our results reveal that the combined activity of WASP and N-WASP is required for peripheral B-cell development and function.
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B-Cell Response during Protozoan Parasite Infections. J Parasitol Res 2012; 2012:362131. [PMID: 22315659 PMCID: PMC3270435 DOI: 10.1155/2012/362131] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 10/06/2011] [Indexed: 02/03/2023] Open
Abstract
In this review, we discuss how protozoan parasites alter immature and mature B cell compartment. B1 and marginal zone (MZ) B cells, considered innate like B cells, are activated during protozoan parasite infections, and they generate short lived plasma cells providing a prompt antibody source. In addition, protozoan infections induce massive B cell response with polyclonal activation that leads to hypergammaglobulnemia with serum antibodies specific for the parasites and self and/or non related antigens. To protect themselves, the parasites have evolved unique ways to evade B cell immune responses inducing apoptosis of MZ and conventional mature B cells. As a consequence of the parasite induced-apoptosis, the early IgM response and an already establish humoral immunity are affected during the protozoan parasite infection. Moreover, some trypanosomatides trigger bone marrow immature B cell apoptosis, influencing the generation of new mature B cells. Simultaneously with their ability to release antibodies, B cells produce cytokines/quemokines that influence the characteristic of cellular immune response and consequently the progression of parasite infections.
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35
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Abstract
B cells are regarded for their capacity to produce antibody. However, recent advances in B cell biology have capitalized on old findings and demonstrated that B cells also release a broad variety of cytokines. As with T helper cells, B cells can be classified into subsets according to the cytokine milieu that they produce. One functional B cell subset, regulatory B cells (Bregs), has recently been shown to contribute to the maintenance of the fine equilibrium required for tolerance. Bregs restrain the excessive inflammatory responses that occur during autoimmune diseases or that can be caused by unresolved infections. Pivotal to Breg function is interleukin-10 (IL-10), which inhibits proinflammatory cytokines and supports regulatory T cell differentiation. This review reports and discusses the factors that are important for Breg differentiation and for their effector function in both mouse and human.
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Affiliation(s)
- Claudia Mauri
- Center for Rheumatology Research, Division of Medicine, University College London, London WC1E 6JF, United Kingdom.
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36
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Habib T, Funk A, Rieck M, Brahmandam A, Dai X, Panigrahi AK, Luning Prak ET, Meyer-Bahlburg A, Sanda S, Greenbaum C, Rawlings DJ, Buckner JH. Altered B cell homeostasis is associated with type I diabetes and carriers of the PTPN22 allelic variant. THE JOURNAL OF IMMUNOLOGY 2011; 188:487-96. [PMID: 22105996 DOI: 10.4049/jimmunol.1102176] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The PTPN22 genetic variant 1858T, encoding Lyp620W, is associated with multiple autoimmune disorders for which the production of autoantibodies is a common feature, suggesting a loss of B cell tolerance. Lyp620W results in blunted BCR signaling in memory B cells. Because BCR signal strength is tightly coupled to central and peripheral tolerance, we examined whether Lyp620W impacts peripheral B cell homeostasis in healthy individuals heterozygous for the PTPN221858T variant. We found that these subjects display alterations in the composition of the B cell pool that include specific expansion of the transitional and anergic IgD(+)IgM(-)CD27(-) B cell subsets. The PTPN22 1858T variant was further associated with significantly diminished BCR signaling and a resistance to apoptosis in both transitional and naive B cells. Strikingly, parallel changes in both BCR signaling and composition of B cell compartment were observed in type 1 diabetic subjects, irrespective of PTPN22 genotype, revealing a novel immune phenotype and likely shared mechanisms leading to a loss of B cell tolerance. Our combined findings suggest that Lyp620W-mediated effects, due in part to the altered BCR signaling threshold, contribute to breakdown of peripheral tolerance and the entry of autoreactive B cells into the naive B cell compartment.
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Affiliation(s)
- Tania Habib
- Translational Research Program, Benaroya Research Institute, Seattle, WA 98101, USA
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37
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Oldham AL, Miner CA, Wang HC, Webb CF. The transcription factor Bright plays a role in marginal zone B lymphocyte development and autoantibody production. Mol Immunol 2011; 49:367-79. [PMID: 21963220 DOI: 10.1016/j.molimm.2011.09.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 09/07/2011] [Accepted: 09/12/2011] [Indexed: 10/17/2022]
Abstract
Previous data suggested that constitutive expression of the transcription factor Bright (B cell regulator of immunoglobulin heavy chain transcription), normally tightly regulated during B cell differentiation, was associated with autoantibody production. Here we show that constitutive Bright expression results in skewing of mature B lineage subpopulations toward marginal zone cells at the expense of the follicular subpopulation. C57Bl/6 transgenic mice constitutively expressing Bright in B lineage cells generated autoantibodies that were not the result of global increases in immunoglobulin or of breaches in key tolerance checkpoints typically defective in other autoimmune mouse models. Rather, autoimmunity correlated with increased numbers of marginal zone B cells and alterations in the phenotype and gene expression profiles of lymphocytes within the follicular B cell compartment. These data suggest a novel role for Bright in the normal development of mature B cell subsets and in autoantibody production.
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Affiliation(s)
- Athenia L Oldham
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
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38
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Cao D, Khmaladze I, Jia H, Bajtner E, Nandakumar KS, Blom T, Mo JA, Holmdahl R. Pathogenic Autoreactive B Cells Are Not Negatively Selected toward Matrix Protein Collagen II. THE JOURNAL OF IMMUNOLOGY 2011; 187:4451-8. [DOI: 10.4049/jimmunol.1101378] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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39
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B regulatory cells and the tumor-promoting actions of TNF-α during squamous carcinogenesis. Proc Natl Acad Sci U S A 2011; 108:10662-7. [PMID: 21670304 DOI: 10.1073/pnas.1100994108] [Citation(s) in RCA: 252] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The inflammatory cytokine TNF-α has been recognized as a critical tumor promoter, but the effector cells that mediate its action have not been fully characterized. Because B cells regulate squamous and prostate carcinogenesis, and Tnf(-/-) mice harbor B-cell defects, we investigated the hypothesis that B cells are important effector cells for TNF-α-mediated promotion of cancer development. Using an adoptive transfer strategy and the 7,12-dimethylbenz[α]anthracene/terephthalic acid (DMBA/TPA) two-stage model of skin carcinogenesis, we found that both B cells and TNF-α are critical for the development of DMBA/TPA-induced papilloma. Transfer of B cells from DMBA/TPA-treated wild-type mice to Tnf(-/-) mice rescued papilloma development to a wild-type level, a result not observed when B cells from Tnf(-/-) mice were transferred to Rag2(-/-) mice or when TNF-α was eliminated selectively in B cells. Resistance to papilloma development in Tnf(-/-) mice was associated with increased IFN-γ and CD8(+) T cells in skin and a significant reduction in IL-10-producing B regulatory cells alongside an increase in IFN-γ-producing CD8(+) T cells in the spleen. These data indicate that during DMBA/TPA-induced squamous carcinogenesis TNF-α mediates tumor-promoting activity via regulatory B cells that repress antitumor immunity.
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40
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Belver L, de Yébenes VG, Ramiro AR. MicroRNAs prevent the generation of autoreactive antibodies. Immunity 2010; 33:713-22. [PMID: 21093320 DOI: 10.1016/j.immuni.2010.11.010] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 05/14/2010] [Accepted: 09/08/2010] [Indexed: 12/19/2022]
Abstract
MicroRNAs have been shown to be critical for a number of aspects of immune system regulation and function. Here, we have examined the role of microRNAs in terminal B cell differentiation by analyzing Cd19-Cre(ki/+) Dicer1(fl/fl) mice. We found that in the absence of Dicer, the transitional and marginal zone (MZ) B cell compartments were overrepresented and follicular (FO) B cell generation was impaired. microRNA analysis revealed that miR185, a microRNA overexpressed in FO cells, dampened B cell receptor (BCR) signaling through Bruton tyrosine kinase downregulation. Dicer-deficient B cells had a skewed BCR repertoire with hallmarks of autoreactivity, which correlated with high titers of autoreactive antibodies in serum and autoimmune features in females. Together, our results reveal a crucial role for microRNAs in late B cell differentiation and in the establishment of B cell tolerance.
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Affiliation(s)
- Laura Belver
- DNA Hypermutation and Cancer Group, Spanish National Cancer Research Center (CNIO), Madrid 28029, Spain
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41
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Lee-Chang C, Lefranc D, Salleron J, Faveeuw C, Allet C, Vermersch P, Oxombre B, Prin L. Susceptibility to experimental autoimmune encephalomyelitis is associated with altered B-cell subsets distribution and decreased serum BAFF levels. Immunol Lett 2010; 135:108-17. [PMID: 20946917 DOI: 10.1016/j.imlet.2010.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 09/07/2010] [Accepted: 10/04/2010] [Indexed: 12/20/2022]
Abstract
B cells possess the ability to regulate either pathogenic or protective events in several autoimmune diseases such as multiple sclerosis (MS) and its experimental model, experimental autoimmune encephalomyelitis (EAE). Given the extensive use of B-cell-targeting treatments, it appears crucial to more precisely define the dual role of B cells in the progression of the disease. In the present study, we explored the impact of EAE induction on the distribution of potential regulatory B-cell subsets (CD5(+) B1a, marginal zone and transitional 2 B cells) over critical time points in the relapsing-remitting EAE model, SJL/J (H2s). The same approach was carried out in B10.S mice that are resistant to EAE induction, (H2s). The comparative data obtained from these experiments showed that the homeostasis of the regulatory B-cell subsets is altered during the EAE preclinical and acute phases. These observations were associated with a distortion of the BAFF response. All these data suggest the existence of a close relationship between B-cell homeostasis, BAFF response and the susceptibility to develop EAE.
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Affiliation(s)
- Catalina Lee-Chang
- Pôle d'Immunologie EA2686, CHRU de Lille, Université de Lille Nord de France, France
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42
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Alter G, Moody MA. The humoral response to HIV-1: new insights, renewed focus. J Infect Dis 2010; 202 Suppl 2:S315-22. [PMID: 20846039 DOI: 10.1086/655654] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
During the past 2 decades, significant advances in our understanding of the humoral immune response to human immunodeficiency virus type 1 (HIV-1) infection have been made, yet a tremendous amount of work lies ahead. Despite these advances, strategies to reliably induce antibodies that can control HIV-1 infection are still critically needed. However, recent advances in our understanding of the kinetics, specificity, and function of early humoral responses offer alternative new approaches to attain this goal. These results, along with the new broadly neutralizing antibody specificities, the role for other antibody functions, the increased understanding of HIV-1-induced changes to B cell biology, and results from the RV144 "Thai" trial showing potential modest sterilizing protection by nonneutralizing antibody responses, have renewed focus on the humoral system. In this review, recent advances in our understanding of the earliest humoral responses are discussed, highlighting presentations from the meeting on the Biology of Acute HIV Infection.
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Affiliation(s)
- Galit Alter
- Ragon Institute of MGH, Massachusetts Institute of Technology and Harvard University, Infectious Disease Unit, Massachusetts General Hospital, and Division of AIDS, Harvard Medical School, Boston, MA 02129, USA.
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43
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Black CL, Muok EMO, Mwinzi PNM, Carter JM, Karanja DMS, Secor WE, Colley DG. Increases in levels of schistosome-specific immunoglobulin E and CD23(+) B cells in a cohort of Kenyan children undergoing repeated treatment and reinfection with Schistosoma mansoni. J Infect Dis 2010; 202:399-405. [PMID: 20560767 DOI: 10.1086/653828] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Age prevalence curves for areas in which schistosomiasis is endemic suggest that humans develop partial immunity to reinfection beginning in early adolescence. We conducted a 2-year longitudinal study to determine whether children infected with Schistosoma mansoni develop protection-related immune responses after treatment with praziquantel and whether the development of these immune responses is accelerated by frequent treatment after reinfection. METHODS Children (8-10 years old) were tested for S. mansoni every 4 months and treated with praziquantel when positive (arm A; n=68) or were tested and treated at the end of the 2-year follow-up period (arm B; n=49). RESULTS Children in arm A who remained free of infection during follow-up had significantly higher baseline levels of schistosome-specific immunoglobulin E (IgE) than did children with > or =2 repeat diagnoses of S. mansoni infection. Children with > or =2 repeat diagnoses of S. mansoni infection had significantly increased levels of anti-schistosome IgE and CD23(+) B cells after receiving > or =3 praziquantel treatments over the course of follow-up. No increase in either parameter was seen in children who received only the baseline praziquantel treatment. CONCLUSIONS B cell activation and anti-schistosome IgE are associated with resistance to S. mansoni in children, and these immunological parameters can be increased by multiple rounds of infections and praziquantel-induced cures.
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Affiliation(s)
- Carla L Black
- Center for Tropical and Emerging Global Diseases and Department of Microbiology, University of Georgia, Athens, Georgia 30602-3799, USA
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44
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Maréchal Y, Quéant S, Polizzi S, Pouillon V, Schurmans S. Inositol 1,4,5-trisphosphate 3-kinase B controls survival and prevents anergy in B cells. Immunobiology 2010; 216:103-9. [PMID: 20452702 DOI: 10.1016/j.imbio.2010.03.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2009] [Revised: 03/10/2010] [Accepted: 03/25/2010] [Indexed: 10/19/2022]
Abstract
Inositol 1,4,5-trisphosphate 3-kinase B (or Itpkb) and inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4), its reaction product, play an important role in the control of B lymphocyte fate and function in vivo. In order to investigate the fine mechanisms of Itpkb and Ins(1,3,4,5)P4 action in B cells, we crossed Itpkb(-/-) mice with transgenic mice expressing a 3-83μδ B cell receptor (BCR) specific for membrane-bound MHC-I H2-K(b) and H2-K(k) molecules. On a non-deleting H2-K(d) genetic background, we show that Itpkb is important for the control of Bim protein expression and B cell survival rather than for the control of B cell development from one stage to another. Analyses of cell surface markers expression, proapoptotic Bim protein expression, in vitro survival and in vivo turnover demonstrated that BCR transgenic Itpkb(-/-) B cells exhibit an anergic phenotype with the notable exception of their enhanced antigen-induced calcium signalling. On a deleting H2-K(b) genetic background, we show that Itpkb is not essential for BCR editing or negative selection. These data establish Itpkb as an important regulator of B cell survival and anergy in vivo.
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Affiliation(s)
- Yoann Maréchal
- Institut de Recherches Interdisciplinaires en Biologie Humaine et Moléculaire (IRIBHM), Institut de Biologie et de Médecine Moléculaires (IBMM), Faculté de Médecine, Université Libre de Bruxelles, Gosselies, Belgium.
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45
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Abstract
Toll-like receptors (TLR) play a central role in the initiation of the innate immune response to pathogens. Upon recognition of molecular motifs specific for microbial molecules TLR mediate pro-inflammatory cytokine secretion and enhance antigen presentation; in B cells they further promote expansion, class switch recombination and immunoglobulin secretion. As a result of their adjuvant properties, TLR ligands have become an integral component of antimicrobial vaccines. In spite of this, little is known of the direct effects of TLR engagement on B-lymphocyte function. The scope of this review is to outline the differences in TLR expression and reactivity in murine and human B-cell subsets and to provide an overview of the currently available literature. We will further discuss the possible roles of TLR in regulating B-cell effector functions and shaping antibody-mediated defence against microbial pathogens in vivo.
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46
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Sadri N, Lu JY, Badura ML, Schneider RJ. AUF1 is involved in splenic follicular B cell maintenance. BMC Immunol 2010; 11:1. [PMID: 20064252 PMCID: PMC2824733 DOI: 10.1186/1471-2172-11-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Accepted: 01/11/2010] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The adenosine/uridine-rich element (ARE)-binding protein AUF1 functions to regulate the inflammatory response through the targeted degradation of cytokine and other mRNAs that contain specific AREs in their 3' noncoding region (3' NCR). To investigate the role of AUF1 in the immune system, we characterized the lymphoid compartments of AUF1-deficient mice. RESULTS Mice lacking AUF1 exhibit an altered proportion and size of splenic B cell subsets. We show prominent apoptosis in splenic B cell follicles and reduced expression of Bcl-2, A1, and Bcl-XL correlate with increased turnover and significant reduction in the number and proportion of splenic FO B cells in AUF1-deficient mice. In addition, AUF1-deficient mice exhibit a sharp decrease in splenic size and lymphocyte cellularity. Bone marrow transfer studies demonstrate that AUF1 deficiency induces cell-autonomous defects in mature B cell subsets but not in the overall number of splenocytes. Reconstitution of irradiated adult AUF1-deficient mice with wild-type bone marrow restores the proportion of FO and marginal zone (MZ) B cells, but does not rescue the decrease in the number of splenocytes. Functionally, AUF1-deficient mice mount an attenuated response to T cell-independent (TI) antigen, which correlates with impaired MZ B cell function. CONCLUSION These data indicate that AUF1 is important in the maintenance of splenic FO B cells and adequate humoral immune responses.
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Affiliation(s)
- Navid Sadri
- Department of Microbiology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
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Moreno-García ME, Sommer K, Haftmann C, Sontheimer C, Andrews SF, Rawlings DJ. Serine 649 phosphorylation within the protein kinase C-regulated domain down-regulates CARMA1 activity in lymphocytes. THE JOURNAL OF IMMUNOLOGY 2009; 183:7362-70. [PMID: 19917688 DOI: 10.4049/jimmunol.0902438] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Phosphorylation of CARMA1 is a crucial event initiating the assembly of IkappaB kinase and JNK signaling complexes downstream of activated Ag receptors. We previously mapped three protein kinase C (PKC) target sites in murine CARMA1 in vitro, and demonstrated that mutation of two of these serines (S564 and S657) resulted in reduced NF-kappaB activation, whereas mutation of the third serine (S649) had no clear effect. In this study, we report that when low concentrations of Ag receptor activators are used, loss of S649 (by mutation to alanine) promotes enhanced IkappaB kinase and JNK activation in both B and T cell lines. Reconstitution of CARMA1(-/-) DT40 B cells with CARMA1 S649A leads to increased cell death and reduced cell growth in comparison to wild-type CARMA1, likely a result of enhanced JNK activation. To directly determine whether S649 is modified in vivo, we generated phospho-specific Abs recognizing phospho-S649, and phospho-S657 as a positive control. Although phospho-S657 peaked and declined rapidly after Ag receptor stimulation, phospho-S649 occurred later and was maintained for a significantly longer period poststimulation in both B and T cells. Interestingly, phospho-S657 was completely abolished in PKCbeta-deficient B cells, whereas delayed phosphorylation at S649 was partially intact and depended, in part, upon novel PKC activity. Thus, distinct PKC-mediated CARMA1 phosphorylation events exert opposing effects on the activation status of CARMA1. We propose that early phosphorylation events at S657 and S564 promote the initial assembly of the CARMA1 signalosome, whereas later phosphorylation at S649 triggers CARMA1 down-regulation.
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Affiliation(s)
- Miguel E Moreno-García
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, WA 98109, USA
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Khan WN. B cell receptor and BAFF receptor signaling regulation of B cell homeostasis. THE JOURNAL OF IMMUNOLOGY 2009; 183:3561-7. [PMID: 19726767 DOI: 10.4049/jimmunol.0800933] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
B lymphocyte homeostasis depends on tonic and induced BCR signaling and receptors sensitive to trophic factors, such as B cell-activating factor receptor (BAFF-R or BR3) during development and maintenance. This review will discuss growing evidence suggesting that the signaling mechanisms that maintain B cell survival and metabolic fitness during selection at transitional stages and survival after maturation rely on cross-talk between BCR and BR3 signaling. Recent findings have also begun to unravel the molecular mechanisms underlying this crosstalk. In this review I also propose a model for regulating the amplitude of BCR signaling by a signal amplification loop downstream of the BCR involving Btk and NF-kappaB that may facilitate BCR-dependent B cell survival as well as its functional coupling to BR3 for the growth and survival of B lymphocytes.
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Affiliation(s)
- Wasif N Khan
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
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Castro I, Wright JA, Damdinsuren B, Hoek KL, Carlesso G, Shinners NP, Gerstein RM, Woodland RT, Sen R, Khan WN. B cell receptor-mediated sustained c-Rel activation facilitates late transitional B cell survival through control of B cell activating factor receptor and NF-kappaB2. THE JOURNAL OF IMMUNOLOGY 2009; 182:7729-37. [PMID: 19494297 DOI: 10.4049/jimmunol.0803281] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Signaling from the BCR and B cell activating factor receptor (BAFF-R or BR3) differentially regulates apoptosis within early transitional (T1) and late transitional (T2; CD21(int)-T2) B cells during selection processes to generate mature B lymphocytes. However, molecular mechanisms underlying the differential sensitivity of transitional B cells to apoptosis remain unclear. In this study, we demonstrate that BCR signaling induced more long-term c-Rel activation in T2 and mature than in T1 B cells leading to increased expression of anti-apoptotic genes as well as prosurvival BAFF-R and its downstream substrate p100 (NF-kappaB2). Sustained c-Rel activation required de novo c-Rel gene transcription and translation via Btk-dependent mechanisms. Like T1 cells, mature B cells from Btk- and c-Rel-deficient mice also failed to activate these genes. These findings suggest that the gain of survival potential within transitional B cells is dependent on the ability to produce a long-term c-Rel response, which plays a critical role in T2 B cell survival and differentiation in vivo by inducing anti-apoptotic genes, BAFF-R and NF-kappaB2, an essential component for BAFF-R survival signaling. Thus, acquisition of resistance to apoptosis during transitional B cell maturation is achieved by integration of BCR and BAFF-R signals.
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Affiliation(s)
- Iris Castro
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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Abstract
Human marginal zone (MZ) B cells are, in a sense, a new entity. Although they share many properties with their mouse counterpart, they also display striking differences, such as the capacity to recirculate and the presence of somatic mutations in their B cell receptor. These differences are the reason they are often not considered a separate, rodent-like B cell lineage, but rather are considered IgM memory B cells. We review here our present knowledge concerning this subset and the arguments in favor of the proposition that humans have evolved for their MZ B cell compartment a separate B cell population that develops and diversifies its Ig receptor during ontogeny outside T-dependent or T-independent immune responses.
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Affiliation(s)
- Jean-Claude Weill
- INSERM U783, Développement du Système Immunitaire, Université Paris Descartes, Faculté de Médecine, Site Necker-Enfants Malades, 75730 Paris Cedex 15, France.
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