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Fiske BE, Wemlinger SM, Crute BW, Getahun A. The Src-family kinase Lyn plays a critical role in establishing and maintaining B cell anergy by suppressing PI3K-dependent signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.21.595208. [PMID: 38826354 PMCID: PMC11142063 DOI: 10.1101/2024.05.21.595208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Although the Src family kinase (SFK) Lyn is known to be involved in induction and maintenance of peripheral B cell tolerance, the molecular basis of its action in this context remains unclear. This question has been approached using conventional as well as B cell-targeted knockouts of Lyn, with varied conclusions likely confused by collateral loss of Lyn functions in B cell and myeloid cell development and activation. Here we utilized a system in which Lyn gene deletion is tamoxifen inducible and B cell restricted. This system allows acute elimination of Lyn in B cells without off-target effects. This genetic tool was employed in conjunction with immunoglobulin transgenic mice in which peripheral B cells are autoreactive. DNA reactive Ars/A1 B cells require continuous inhibitory signaling, mediated by the inositol phosphatase SHIP-1 and the tyrosine phosphatase SHP-1, to maintain an unresponsive (anergic) state. Here we show that Ars/A1 B cells require Lyn to establish and maintain B cell unresponsiveness. Lyn primarily functions by restricting PI3K-dependent signaling pathways. This Lyn-dependent mechanism complements the impact of reduced mIgM BCR expression to restrict BCR signaling in Ars/A1 B cells. Our findings suggest that a subset of autoreactive B cells requires Lyn to become anergic and that the autoimmunity associated with dysregulated Lyn function may, in part, be due to an inability of these autoreactive B cells to become tolerized.
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Fiske BE, Getahun A. Failed Downregulation of PI3K Signaling Makes Autoreactive B Cells Receptive to Bystander T Cell Help. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 212:1150-1160. [PMID: 38353615 PMCID: PMC10948302 DOI: 10.4049/jimmunol.2300108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 01/16/2024] [Indexed: 02/27/2024]
Abstract
The role of T cell help in autoantibody responses is not well understood. Because tolerance mechanisms govern both T and B cell responses, one might predict that both T cell tolerance and B cell tolerance must be defeated in autoantibody responses requiring T cell help. To define whether autoreactive B cells depend on T cells to generate autoantibody responses, we studied the role of T cells in murine autoantibody responses resulting from acute B cell-specific deletion of regulatory phosphatases. Ars/A1 B cells are DNA reactive and require continuous inhibitory signaling by the tyrosine phosphatase SHP-1 and the inositol phosphatases SHIP-1 and PTEN to maintain unresponsiveness. Acute B cell-restricted deletion of any of these phosphatases results in an autoantibody response. In this study, we show that CD40-CD40L interactions are required to support autoantibody responses of B cells whose anergy has been compromised. If the B cell-intrinsic driver of loss of tolerance is failed negative regulation of PI3K signaling, bystander T cells provide sufficient CD40-mediated signal 2 to support an autoantibody response. However, although autoantibody responses driven by acute B cell-targeted deletion of SHP-1 also require T cells, bystander T cell help does not suffice. These results demonstrate that upregulation of PI3K signaling in autoreactive B cells, recapitulating the effect of multiple autoimmunity risk alleles, promotes autoantibody responses both by increasing B cells' cooperation with noncognate T cell help and by altering BCR signaling. Receptiveness to bystander T cell help enables autoreactive B cells to circumvent the fail-safe of T cell tolerance.
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Affiliation(s)
- Brigita E. Fiske
- Department of Immunology and Microbiology, University of Colorado SOM, Aurora, CO, USA
| | - Andrew Getahun
- Department of Immunology and Microbiology, University of Colorado SOM, Aurora, CO, USA
- Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO, USA
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Graham JB, Swarts JL, Leist SR, Schäfer A, Bell TA, Hock P, Farrington J, Shaw GD, Ferris MT, Pardo-Manuel de Villena F, Baric RS, Lund JM. Unique immune profiles in collaborative cross mice linked to survival and viral clearance upon infection. iScience 2024; 27:109103. [PMID: 38361611 PMCID: PMC10867580 DOI: 10.1016/j.isci.2024.109103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/18/2023] [Accepted: 01/30/2024] [Indexed: 02/17/2024] Open
Abstract
The response to infection is generally heterogeneous and diverse, with some individuals remaining asymptomatic while others present with severe disease or a diverse range of symptoms. Here, we address the role of host genetics on immune phenotypes and clinical outcomes following viral infection by studying genetically diverse mice from the Collaborative Cross (CC), allowing for use of a small animal model with controlled genetic diversity while maintaining genetic replicates. We demonstrate variation by deeply profiling a broad range of innate and adaptive immune cell phenotypes at steady-state in 63 genetically distinct CC mouse strains and link baseline immune signatures with virologic and clinical disease outcomes following infection of mice with herpes simplex virus 2 (HSV-2) or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This work serves as a resource for CC strain selection based on steady-state immune phenotypes or disease presentation upon viral infection, and further, points to possible pre-infection immune correlates of survival and early viral clearance upon infection.
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Affiliation(s)
- Jessica B. Graham
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Jessica L. Swarts
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Sarah R. Leist
- Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Alexandra Schäfer
- Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Timothy A. Bell
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Pablo Hock
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Joe Farrington
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ginger D. Shaw
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Martin T. Ferris
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Fernando Pardo-Manuel de Villena
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ralph S. Baric
- Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jennifer M. Lund
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Department of Global Health, University of Washington, Seattle, WA, USA
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Ferri DM, Nassar C, Manion KP, Kim M, Baglaenko Y, Muñoz-Grajales C, Wither JE. Elevated Levels of Interferon-α Act Directly on B Cells to Breach Multiple Tolerance Mechanisms Promoting Autoantibody Production. Arthritis Rheumatol 2023; 75:1542-1555. [PMID: 36807718 DOI: 10.1002/art.42482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 01/16/2023] [Accepted: 02/14/2023] [Indexed: 02/23/2023]
Abstract
OBJECTIVE Elevated levels of serum interferon-α (IFNα) and the disruption of B cell tolerance are central to systemic lupus erythematosus (SLE) immunopathogenesis; however, the relationship between these 2 processes remains unclear. The purpose of this study was to investigate the impact of elevated IFNα levels on B cell tolerance mechanisms in vivo and determine whether any changes observed were due to the direct effect of IFNα on B cells. METHODS Two classical mouse models of B cell tolerance were used in conjunction with an adenoviral vector encoding IFNα to mimic the sustained elevations of IFNα seen in SLE. The role of B cell IFNα signaling, T cells, and Myd88 signaling was determined using B cell-specific IFNα receptor-knockout, CD4+ T cell-depleted, or Myd88-knockout mice, respectively. Flow cytometry, enzyme-linked immunosorbent assay, real-time quantitative polymerase chain reaction, and cell cultures were used to study the effects of elevated IFNα on the immunologic phenotype. RESULTS Elevation of serum IFNα disrupts multiple B cell tolerance mechanisms and leads to autoantibody production. This disruption was dependent upon B cell expression of IFNα receptor. Many of the IFNα-mediated alterations also required the presence of CD4+ T cells as well as Myd88, suggesting that IFNα acts directly on B cells to modify their response to Myd88 signaling and their ability to interact with T cells. CONCLUSION The results provide evidence that elevated IFNα levels act directly on B cells to facilitate autoantibody production and further highlight the importance of IFN signaling as a potential therapeutic target in SLE.
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Affiliation(s)
- Dario M Ferri
- Schroeder Arthritis Institute, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Carol Nassar
- Schroeder Arthritis Institute, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Kieran P Manion
- Schroeder Arthritis Institute, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Michael Kim
- Schroeder Arthritis Institute, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Yuriy Baglaenko
- Schroeder Arthritis Institute, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Carolina Muñoz-Grajales
- Schroeder Arthritis Institute, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Joan E Wither
- Schroeder Arthritis Institute, Krembil Research Institute, and Division of Rheumatology, Schroeder Arthritis Institute, University Health Network, and Departments of Medicine and Immunology, University of Toronto, Toronto, Ontario, Canada
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5
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Fiske BE, Getahun A. Failed down-regulation of PI3K signaling makes autoreactive B cells receptive to bystander T cell help. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.23.525206. [PMID: 36747655 PMCID: PMC9900797 DOI: 10.1101/2023.01.23.525206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The role of T cell help in autoantibody responses is not well understood. Since tolerance mechanisms govern both T and B cell responses, one might predict that both T cell tolerance and B cell tolerance must be defeated in autoantibody responses requiring T cell help. To define whether autoreactive B cells depend on T cells to generate autoantibody responses, we studied the role of T cells in autoantibody responses resulting from acute cell-specific deletion of regulatory phosphatases. Ars/A1 B cells are DNA-reactive and require continuous inhibitory signaling by the tyrosine phosphatase SHP-1 and the inositol phosphatases SHIP-1 and PTEN to maintain unresponsiveness. Acute B cell-restricted deletion of any of these phosphatases results in an autoantibody response. Here we show that CD40-CD40L interactions are required to support autoantibody responses of B cells whose anergy has been compromised. If the B cell-intrinsic driver of loss of tolerance is failed negative regulation of PI3K signaling, bystander T cells provide sufficient CD40-mediated signal 2 to support an autoantibody response. However, while autoantibody responses driven by acute B cell-targeted deletion of SHP-1 also require T cells, bystander T cell help does not suffice. These results demonstrate that upregulation of PI3K signaling in autoreactive B cells, recapitulating the effect of multiple autoimmunity risk alleles, promotes autoantibody responses both by increasing B cells’ cooperation with non-cognate T cell help, as well as by altering BCR signaling. Receptiveness to bystander T cell help enables autoreactive B cells to circumvent the fail-safe of T cell tolerance. Significance Phosphatase suppression of PI3K signaling is an important mechanism by which peripheral autoreactive B cells are kept in an unresponsive/anergic state. Loss of this suppression, due to genetic alleles that confer risk of autoimmunity, often occurs in autoreactive B cells of individuals who develop autoimmune disease. Here we demonstrate that de-repression of PI3K signaling promotes autoantibody responses of a DNA-reactive B cell clone by relaxing dependence of autoantibody responses on T cell-derived helper signals. These results suggest that impaired regulation of PI3K signaling can promote autoantibody responses in two ways: by restoring antigen receptor signaling and by enabling autoreactive B cells to circumvent restrictions imposed by T cell tolerance mechanisms.
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Getahun A. Role of inhibitory signaling in peripheral B cell tolerance*. Immunol Rev 2022; 307:27-42. [PMID: 35128676 PMCID: PMC8986582 DOI: 10.1111/imr.13070] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 12/16/2022]
Abstract
At least 20% of B cells in the periphery expresses an antigen receptor with a degree of self-reactivity. If activated, these autoreactive B cells pose a risk as they can contribute to the development of autoimmune diseases. To prevent their activation, both B cell-intrinsic and extrinsic tolerance mechanisms are in place in healthy individuals. In this review article, I will focus on B cell-intrinsic mechanisms that prevent the activation of autoreactive B cells in the periphery. I will discuss how inhibitory signaling circuits are established in autoreactive B cells, focusing on the Lyn-SHIP-1-SHP-1 axis, how they contribute to peripheral immune tolerance, and how disruptions of these circuits can contribute to the development of autoimmunity.
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Affiliation(s)
- Andrew Getahun
- Department of Immunology and Microbiology University of Colorado SOM Aurora Colorado USA
- Department of Immunology and Genomic Medicine National Jewish Health Denver Colorado USA
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7
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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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Roberto MP, Varano G, Vinas-Castells R, Holmes AB, Kumar R, Pasqualucci L, Farinha P, Scott DW, Dominguez-Sola D. Mutations in the transcription factor FOXO1 mimic positive selection signals to promote germinal center B cell expansion and lymphomagenesis. Immunity 2021; 54:1807-1824.e14. [PMID: 34380064 DOI: 10.1016/j.immuni.2021.07.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/26/2021] [Accepted: 07/13/2021] [Indexed: 12/27/2022]
Abstract
The transcription factor forkhead box O1 (FOXO1), which instructs the dark zone program to direct germinal center (GC) polarity, is typically inactivated by phosphatidylinositol 3-kinase (PI3K) signals. Here, we investigated how FOXO1 mutations targeting this regulatory axis in GC-derived B cell non-Hodgkin lymphomas (B-NHLs) contribute to lymphomagenesis. Examination of primary B-NHL tissues revealed that FOXO1 mutations and PI3K pathway activity were not directly correlated. Human B cell lines bearing FOXO1 mutations exhibited hyperactivation of PI3K and Stress-activated protein kinase (SAPK)/Jun amino-terminal kinase (JNK) signaling, and increased cell survival under stress conditions as a result of alterations in FOXO1 transcriptional affinities and activation of transcriptional programs characteristic of GC-positive selection. When modeled in mice, FOXO1 mutations conferred competitive advantage to B cells in response to key T-dependent immune signals, disrupting GC homeostasis. FOXO1 mutant transcriptional signatures were prevalent in human B-NHL and predicted poor clinical outcomes. Thus, rather than enforcing FOXO1 constitutive activity, FOXO1 mutations enable co-option of GC-positive selection programs during the pathogenesis of GC-derived lymphomas.
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Affiliation(s)
- Mark P Roberto
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Gabriele Varano
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Rosa Vinas-Castells
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Antony B Holmes
- Institute for Cancer Genetics, Columbia University Medical Center, New York, NY 10032, USA
| | - Rahul Kumar
- Institute for Cancer Genetics, Columbia University Medical Center, New York, NY 10032, USA
| | - Laura Pasqualucci
- Institute for Cancer Genetics, Columbia University Medical Center, New York, NY 10032, USA; Department of Pathology, Columbia University Medical Center, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032, USA
| | - Pedro Farinha
- Center for Lymphoid Cancer, British Columbia Cancer, Vancouver, BC V5Z 1L3, Canada
| | - David W Scott
- Center for Lymphoid Cancer, British Columbia Cancer, Vancouver, BC V5Z 1L3, Canada
| | - David Dominguez-Sola
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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Modulation of Splenic B Cell Subsets during Experimental Leishmania donovani Infection in BALB/c Mice. Pathogens 2021; 10:pathogens10070814. [PMID: 34209841 PMCID: PMC8308600 DOI: 10.3390/pathogens10070814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 06/17/2021] [Accepted: 06/25/2021] [Indexed: 11/29/2022] Open
Abstract
Sodium antimonials are one of the major and common drugs used against visceral form leishmaniasis (VL). However, the development of drug resistance makes it difficult to manage this disease. Current work investigates the modulation of splenic B cells during experimental infection with antimony-sensitive and -resistant Leishmania donovani infection. Here we phenotypically characterized splenic B cell subsets in BALB/c mice infected with antimony drug-sensitive and -resistant VL strains using flow-cytometry method. In the splenocytes we noticed increased number of Transitional T3 B cells and B1a B cells in drug-resistant VL strain infection. Besides, we also observed alteration in Follicular B cell population of antimony-resistant strain infected mice. Drug-resistant strain induced secretion of elevated level of IL-10 from B1a B cells and IL-6 from Transitional T3 B cell subsets in the splenocytes. Purified splenic B cells from antimony drug-resistant strain infected mice showed decrease in the Lyn kinase gene expression compared to sensitive strain infected and uninfected mice. The current study provides insight into changes in host splenic B-cell subsets during experimental infection with antimony-sensitive and -resistant L. donovani in murine model.
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10
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BAFF promotes heightened BCR responsiveness and manifestations of chronic GVHD after allogeneic stem cell transplantation. Blood 2021; 137:2544-2557. [PMID: 33534893 PMCID: PMC8109011 DOI: 10.1182/blood.2020008040] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 01/21/2021] [Indexed: 12/25/2022] Open
Abstract
Patients with chronic graft-versus-host disease (cGVHD) have increased B cell-activating factor (BAFF) levels, but whether BAFF promotes disease after allogeneic bone marrow transplantation (allo-BMT) remains unknown. In a major histocompatibility complex-mismatched model with cGVHD-like manifestations, we first examined B-lymphopenic μMT allo-BMT recipients and found that increased BAFF levels in cGVHD mice were not merely a reflection of B-cell number. Mice that later developed cGVHD had significantly increased numbers of recipient fibroblastic reticular cells with higher BAFF transcript levels. Increased BAFF production by donor cells also likely contributed to cGVHD, because BAFF transcript in CD4+ T cells from diseased mice and patients was increased. cGVHD manifestations in mice were associated with high BAFF/B-cell ratios and persistence of B-cell receptor (BCR)-activated B cells in peripheral blood and lesional tissue. By employing BAFF transgenic (Tg) mice donor cells, we addressed whether high BAFF contributed to BCR activation in cGVHD. BAFF increased NOTCH2 expression on B cells, augmenting BCR responsiveness to surrogate antigen and NOTCH ligand. BAFF Tg B cells had significantly increased protein levels of the proximal BCR signaling molecule SYK, and high SYK protein was maintained by BAFF after in vitro BCR activation or when alloantigen was present in vivo. Using T cell-depleted (BM only) BAFF Tg donors, we found that BAFF promoted cGVHD manifestations, circulating GL7+ B cells, and alloantibody production. We demonstrate that pathologic production of BAFF promotes an altered B-cell compartment and augments BCR responsiveness. Our findings compel studies of therapeutic targeting of BAFF and BCR pathways in patients with cGVHD.
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11
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Dolasia K, Nazar F, Mukhopadhyay S. Mycobacterium tuberculosis PPE18 protein inhibits MHC class II antigen presentation and B cell response in mice. Eur J Immunol 2020; 51:603-619. [PMID: 33084017 DOI: 10.1002/eji.201848071] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 09/22/2020] [Accepted: 10/19/2020] [Indexed: 01/18/2023]
Abstract
PPE18 protein belongs to PE/PPE family of Mycobacterium tuberculosis. We reported earlier that PPE18 protein provides survival advantage to M. tuberculosis during infection. In the current study, we found that PPE18 inhibits MHC class II-mediated antigen presentation by macrophages in a dose-dependent manner without affecting the surface level of MHC class II or co-stimulatory molecules. PPE18 does not affect antigen uptake or presentation of preprocessed peptide by macrophages. Antigen degradation was found to be inhibited by PPE18 protein due to perturbation in phagolysosomal acidification. PPE18-mediated inhibition of MHC class II antigen presentation caused poorer activation of CD4 T cells. Mice infected with M. smegmatis expressing PPE18 exhibited reduced maturation and activation of B cells and had decreased Mycobacteria-specific antibody titers. Thus M. tuberculosis probably utilizes PPE18 to inhibit MHC class II antigen presentation causing poorer activation of adaptive immune responses. This study may be useful in understanding host-pathogen interaction and open up directions of designing novel therapeutics targeting PPE18 to tackle this nefarious pathogen.
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Affiliation(s)
- Komal Dolasia
- Laboratory of Molecular Cell Biology, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Faiza Nazar
- Laboratory of Molecular Cell Biology, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India
| | - Sangita Mukhopadhyay
- Laboratory of Molecular Cell Biology, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India
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12
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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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13
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Tan C, Noviski M, Huizar J, Zikherman J. Self-reactivity on a spectrum: A sliding scale of peripheral B cell tolerance. Immunol Rev 2019; 292:37-60. [PMID: 31631352 DOI: 10.1111/imr.12818] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 10/02/2019] [Indexed: 12/16/2022]
Abstract
Efficient mechanisms of central tolerance, including receptor editing and deletion, prevent highly self-reactive B cell receptors (BCRs) from populating the periphery. Despite this, modest self-reactivity persists in (and may even be actively selected into) the mature B cell repertoire. In this review, we discuss new insights into mechanisms of peripheral B cell tolerance that restrain mature B cells from mounting inappropriate responses to endogenous antigens, and place recent work into historical context. In particular, we discuss new findings that have arisen from application of a novel in vivo reporter of BCR signaling, Nur77-eGFP, expression of which scales with the degree of self-reactivity in both monoclonal and polyclonal B cell repertoires. We discuss new and historical evidence that self-reactivity is not just tolerated, but actively selected into the peripheral repertoire. We review recent progress in understanding how dual expression of the IgM and IgD BCR isotypes on mature naive follicular B cells tunes responsiveness to endogenous antigen recognition, and discuss how this may be integrated with other features of clonal anergy. Finally, we discuss how expression of Nur77 itself couples chronic antigen stimulation with B cell tolerance.
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Affiliation(s)
- Corey Tan
- Biomedical Sciences (BMS) Graduate Program, University of California, San Francisco, CA, USA
| | - Mark Noviski
- Biomedical Sciences (BMS) Graduate Program, University of California, San Francisco, CA, USA.,Division of Rheumatology, Department of Medicine, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, University of California, San Francisco, CA, USA
| | - John Huizar
- School of Medicine, HHMI Medical Fellows Program, University of California, San Francisco, CA, USA
| | - Julie Zikherman
- Division of Rheumatology, Department of Medicine, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, University of California, San Francisco, CA, USA
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14
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Sanz I, Wei C, Jenks SA, Cashman KS, Tipton C, Woodruff MC, Hom J, Lee FEH. Challenges and Opportunities for Consistent Classification of Human B Cell and Plasma Cell Populations. Front Immunol 2019; 10:2458. [PMID: 31681331 PMCID: PMC6813733 DOI: 10.3389/fimmu.2019.02458] [Citation(s) in RCA: 274] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 10/01/2019] [Indexed: 12/11/2022] Open
Abstract
The increasingly recognized role of different types of B cells and plasma cells in protective and pathogenic immune responses combined with technological advances have generated a plethora of information regarding the heterogeneity of this human immune compartment. Unfortunately, the lack of a consistent classification of human B cells also creates significant imprecision on the adjudication of different phenotypes to well-defined populations. Additional confusion in the field stems from: the use of non-discriminatory, overlapping markers to define some populations, the extrapolation of mouse concepts to humans, and the assignation of functional significance to populations often defined by insufficient surface markers. In this review, we shall discuss the current understanding of human B cell heterogeneity and define major parental populations and associated subsets while discussing their functional significance. We shall also identify current challenges and opportunities. It stands to reason that a unified approach will not only permit comparison of separate studies but also improve our ability to define deviations from normative values and to create a clean framework for the identification, functional significance, and disease association with new populations.
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Affiliation(s)
- Ignacio Sanz
- Lowance Center for Human Immunology, Emory University, Atlanta, GA, United States.,Division of Rheumatology, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Chungwen Wei
- Lowance Center for Human Immunology, Emory University, Atlanta, GA, United States.,Division of Rheumatology, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Scott A Jenks
- Lowance Center for Human Immunology, Emory University, Atlanta, GA, United States.,Division of Rheumatology, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Kevin S Cashman
- Lowance Center for Human Immunology, Emory University, Atlanta, GA, United States.,Division of Rheumatology, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Christopher Tipton
- Lowance Center for Human Immunology, Emory University, Atlanta, GA, United States.,Division of Rheumatology, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Matthew C Woodruff
- Lowance Center for Human Immunology, Emory University, Atlanta, GA, United States.,Division of Rheumatology, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Jennifer Hom
- Lowance Center for Human Immunology, Emory University, Atlanta, GA, United States.,Division of Rheumatology, Department of Medicine, Emory University, Atlanta, GA, United States
| | - F Eun-Hyung Lee
- Lowance Center for Human Immunology, Emory University, Atlanta, GA, United States.,Division of Pulmonary, Allergy, and Critical Care, Department of Medicine, Emory University, Atlanta, GA, United States
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15
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Chang SH, Kim TJ, Kim Y, Han SS, Lee SK, Sim JH, Kim YJ, Lee SJ, Rhyu IJ, Nam KH, Mohan C, Kim HR. Impacts of GFP-FoxP3 + regulatory T cells on lupus hallmarks differ by genetic background and type of GFP knock-in. Autoimmunity 2019; 52:199-207. [PMID: 31468991 DOI: 10.1080/08916934.2019.1657098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
FoxP3 reporter mice expressing green fluorescence protein (GFP) have been used as a very convenient tool to investigate the impact of regulatory T (Treg) cells on pathogenesis in autoimmune diseases. Here, we found that GFP-FoxP3+ knock-in (KI) mice showed alterations in the production of anti-nuclear autoantibodies (ANAs) and nephritis with different extent, depending on the presence or absence of lupus susceptibility gene locus 1 (Sle1) and KI method: contrasting with B6.Sle1.fGFP-FoxP3 mice, expressing GFP via N-terminal insertion, B6.Sle1.iGFP-FoxP3, expressing GFP via bicistronic internal ribosome entry site-driven promotion, exhibited significantly lower penetrance of serum ANA, comparing to control B6.Sle1 mice. Moreover, B6.Sle1.GFP-FoxP3+ mice reduced the Sle1-induced splenomegaly and B-cell expansion independently of the KI method employed, mainly by reducing the numbers of transitional 1 (T1) B cells and CD21-CD23- B cells, including plasmablasts and plasma cells. The absolute numbers of both splenic CD4+ T cells and Treg cells from B6.Sle1.GFP-FoxP3 KI mice were significantly reduced but their proportion was not changed, compared to B6.Sle1 mice. Although the glomerular basement membranes were thickened in both B6.Sle1 and B6.Sle1.iGFP-FoxP3 mice, they were thinner in B6.Sle1.fGFP-FoxP3 mice. The latter mice expressed more nephrophilic autoantibodies and deposited more complement component 3 in glomeruli compared to B6.iGFP-FoxP3 mice. FoxP3+ Treg cells may modulate B-cell tolerance in lupus-prone B6.Sle1 mice, presumably by modulating pathogenic, nephrophilic autoantibody production and nephritis.
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Affiliation(s)
- Soog-Hee Chang
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Tae-Joo Kim
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Yongbaek Kim
- Laboratory of Veterinary Clinical Pathology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.,Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Seung Seok Han
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sun-Kyung Lee
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ji Hyun Sim
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Young-Joo Kim
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Se Jeong Lee
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Im Joo Rhyu
- Department of Anatomy, Korea University College of Medicine, Seoul, Republic of Korea
| | - Ki-Hoan Nam
- Biomedical Mouse Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongwon-Gun, Republic of Korea
| | - Chandra Mohan
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Hang-Rae Kim
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.,BK21Plus Biomedical Science Project, Seoul National University College of Medicine, Seoul, Republic of Korea.,Medical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
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16
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Getahun A, Cambier JC. Non-Antibody-Secreting Functions of B Cells and Their Contribution to Autoimmune Disease. Annu Rev Cell Dev Biol 2019; 35:337-356. [PMID: 30883216 DOI: 10.1146/annurev-cellbio-100617-062518] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
B cells play multiple important roles in the pathophysiology of autoimmune disease. Beyond producing pathogenic autoantibodies, B cells can act as antigen-presenting cells and producers of cytokines, including both proinflammatory and anti-inflammatory cytokines. Here we review our current understanding of the non-antibody-secreting roles that B cells may play during development of autoimmunity, as learned primarily from reductionist preclinical models. Attention is also given to concepts emerging from clinical studies using B cell depletion therapy, which shed light on the roles of these mechanisms in human autoimmune disease.
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Affiliation(s)
- Andrew Getahun
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA; .,Department of Biomedical Research, National Jewish Health, Denver, Colorado 80206, USA
| | - John C Cambier
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA; .,Department of Biomedical Research, National Jewish Health, Denver, Colorado 80206, USA
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17
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Hobeika E, Dautzenberg M, Levit-Zerdoun E, Pelanda R, Reth M. Conditional Selection of B Cells in Mice With an Inducible B Cell Development. Front Immunol 2018; 9:1806. [PMID: 30127788 PMCID: PMC6087743 DOI: 10.3389/fimmu.2018.01806] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/23/2018] [Indexed: 11/13/2022] Open
Abstract
Developing B cells undergo defined maturation steps in the bone marrow and in the spleen. The timing and the factors that control these differentiation steps are not fully understood. By targeting the B cell-restricted mb-1 locus to generate an mb-1 allele that expresses a tamoxifen inducible Cre and another allele in which mb-1 expression can be controlled by Cre, we have established a mouse model with an inducible B cell compartment. With these mice, we studied in detail the kinetics of B cell development and the consequence of BCR activation at a defined B cell maturation stage. Contrary to expectations, transitional 1-B cells exposed to anti-IgM reagents in vivo did not die but instead developed into transitional 2 (T2)-B cells with upregulated Bcl-2 expression. We show, however, that these T2-B cells had an increased dependency on the B cell survival factor B cell activating factor when compared to non-stimulated B cells. Overall, our findings indicate that the inducible mb-1 mouse strain represents a useful model, which allows studying the signals that control the selection of B cells in greater detail.
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Affiliation(s)
- Elias Hobeika
- Centre for Biological Signaling Studies (BIOSS), Biology III, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Marcel Dautzenberg
- Centre for Biological Signaling Studies (BIOSS), Biology III, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Ella Levit-Zerdoun
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.,Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,International Max Planck Research School for Molecular and Cellular Biology, Freiburg, Germany
| | - Roberta Pelanda
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Michael Reth
- Centre for Biological Signaling Studies (BIOSS), Biology III, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
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18
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Ottens K, Hinman RM, Barrios E, Skaug B, Davis LS, Li QZ, Castrillon DH, Satterthwaite AB. Foxo3 Promotes Apoptosis of B Cell Receptor-Stimulated Immature B Cells, Thus Limiting the Window for Receptor Editing. THE JOURNAL OF IMMUNOLOGY 2018; 201:940-949. [PMID: 29950509 DOI: 10.4049/jimmunol.1701070] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 06/02/2018] [Indexed: 12/29/2022]
Abstract
Central tolerance checkpoints are critical for the elimination of autoreactive B cells and the prevention of autoimmunity. When autoreactive B cells encounter their Ag at the immature B cell stage, BCR cross-linking induces receptor editing, followed by apoptosis if edited cells remain autoreactive. Although the transcription factor Foxo1 is known to promote receptor editing, the role of the related factor Foxo3 in central B cell tolerance is poorly understood. We find that BCR-stimulated immature B cells from Foxo3-deficient mice demonstrate reduced apoptosis compared with wild type cells. Despite this, Foxo3-/- mice do not develop increased autoantibodies. This suggests that the increased survival of Foxo3-/- immature B cells allows additional rounds of receptor editing, resulting in more cells "redeeming" themselves by becoming nonautoreactive. Indeed, increased Igλ usage and increased recombining sequence recombination among Igλ-expressing cells were observed in Foxo3-/- mice, indicative of increased receptor editing. We also observed that deletion of high-affinity autoreactive cells was intact in the absence of Foxo3 in the anti-hen egg lysozyme (HEL)/membrane-bound HEL model. However, Foxo3 levels in B cells from systemic lupus erythematosus (SLE) patients were inversely correlated with disease activity and reduced in patients with elevated anti-dsDNA Abs. Although this is likely due in part to increased B cell activation in these SLE patients, it is also possible that low-affinity B cells that remain autoreactive after editing may survive inappropriately in the absence of Foxo3 and become activated to secrete autoantibodies in the context of other SLE-associated defects.
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Affiliation(s)
- Kristina Ottens
- Rheumatic Diseases Division, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Rochelle M Hinman
- Rheumatic Diseases Division, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Evan Barrios
- Rheumatic Diseases Division, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Brian Skaug
- Rheumatic Diseases Division, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Laurie S Davis
- Rheumatic Diseases Division, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Quan-Zhen Li
- Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Diego H Castrillon
- Department of Pathology, The University of Texas Southwestern Medical Center, Dallas, TX 75390; and.,Simmons Comprehensive Cancer Center, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Anne B Satterthwaite
- Rheumatic Diseases Division, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390; .,Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
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19
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Richards AL, Howie HL, Kapp LM, Hendrickson JE, Zimring JC, Hudson KE. Innate B-1 B Cells Are Not Enriched in Red Blood Cell Autoimmune Mice: Importance of B Cell Receptor Transgenic Selection. Front Immunol 2017; 8:1366. [PMID: 29163471 PMCID: PMC5675845 DOI: 10.3389/fimmu.2017.01366] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 10/05/2017] [Indexed: 11/13/2022] Open
Abstract
Autoimmune hemolytic anemia (AIHA) results from breakdown of humoral tolerance to RBC antigens. Past analyses of B-cell receptor transgenic (BCR-Tg) mice that recognize RBC autoantigens led to a paradigm in which autoreactive conventional B-2 B cells are deleted whereas extramedullary B-1 B cells escape deletion due to lack of exposure to RBCs. However, BCR-Tg mice utilized to shape the current paradigm were unable to undergo receptor editing or class-switching. Given the importance of receptor editing as mechanism to tolerize autoreactive B cells during central tolerance, we hypothesized that expansion of autoreactive B-1 B cells is a consequence of the inability of the autoreactive BCR to receptor edit. To test this hypothesis, we crossed two separate strains of BCR-Tg mice with transgenic mice expressing the BCR target on RBCs. Both BCR-Tg mice express the same immunoglobulin and, thus, secrete antibodies with identical specificity, but one strain (SwHEL) has normal receptor editing, whereas the other (IgHEL) does not. Similar to other AIHA models, the autoreactive IgHEL strain showed decreased B-2 B cells, an enrichment of B-1 B cells, and detectable anti-RBC autoantibodies and decreased RBC hematocrit and hemoglobin values. However, autoreactive SwHEL mice had induction of tolerance in both B-2 and B-1 B cells with anti-RBC autoantibody production without anemia. These data generate new understanding and challenge the existing paradigm of B cell tolerance to RBC autoantigens. Furthermore, these findings demonstrate that immune responses vary when BCR-Tg do not retain BCR editing and class-switching functions.
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Affiliation(s)
| | - Heather L Howie
- Bloodworks Northwest Research Institute, Seattle, WA, United States
| | - Linda M Kapp
- Bloodworks Northwest Research Institute, Seattle, WA, United States
| | - Jeanne E Hendrickson
- Department of Laboratory Medicine and Pediatrics, Yale University, New Haven, CT, United States
| | - James C Zimring
- Bloodworks Northwest Research Institute, Seattle, WA, United States.,Department of Laboratory Medicine, Division of Hematology, University of Washington, Seattle, WA, United States.,Department of Internal Medicine, Division of Hematology, University of Washington, Seattle, WA, United States
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20
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Phenotyping of autoreactive B cells with labeled nucleosomes in 56R transgenic mice. Sci Rep 2017; 7:13232. [PMID: 29038433 PMCID: PMC5643551 DOI: 10.1038/s41598-017-13422-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/21/2017] [Indexed: 01/22/2023] Open
Abstract
The phenotypic characterization of self-reactive B cells producing autoantibodies is one of the challenges to get further insight in the physiopathology of autoimmune diseases. We took advantage of our previously developed flow cytometry method, using labeled nucleosomes, prominent autoantigens in systemic lupus erythematosus, to analyze the phenotype of self-reactive B cells in the anti-DNA B6.56R mouse model. We showed that splenic anti-nucleosome B cells express mostly kappa light chains and harbor a marginal zone phenotype. Moreover, these autoreactive B cells fail to acquire a germinal center phenotype and are less abundant in the transitional T3 compartment. In conclusion, the direct detection of autoreactive B cells helped determine their phenotypic characteristics and provided a more direct insight into the B cell tolerance process in B6.56R mice. This method constitutes an interesting new tool to study the mechanisms of B cell tolerance breakdown in B6.56R mice crossed with autoimmune prone models.
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21
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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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22
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Dysregulated Lymphoid Cell Populations in Mouse Models of Systemic Lupus Erythematosus. Clin Rev Allergy Immunol 2017; 53:181-197. [DOI: 10.1007/s12016-017-8605-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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23
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Hamilton JA, Li J, Wu Q, Yang P, Luo B, Li H, Bradley JE, Taylor JJ, Randall TD, Mountz JD, Hsu HC. General Approach for Tetramer-Based Identification of Autoantigen-Reactive B Cells: Characterization of La- and snRNP-Reactive B Cells in Autoimmune BXD2 Mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2015; 194:5022-34. [PMID: 25888644 PMCID: PMC4417409 DOI: 10.4049/jimmunol.1402335] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 03/15/2015] [Indexed: 11/19/2022]
Abstract
Autoreactive B cells are associated with the development of several autoimmune diseases, including systemic lupus erythematosus and rheumatoid arthritis. The low frequency of these cells represents a major barrier to their analysis. Ag tetramers prepared from linear epitopes represent a promising strategy for the identification of small subsets of Ag-reactive immune cells. This is challenging given the requirement for identification and validation of linear epitopes and the complexity of autoantibody responses, including the broad spectrum of autoantibody specificities and the contribution of isotype to pathogenicity. Therefore, we tested a two-tiered peptide microarray approach, coupled with epitope mapping of known autoantigens, to identify and characterize autoepitopes using the BXD2 autoimmune mouse model. Microarray results were verified through comparison with established age-associated profiles of autoantigen specificities and autoantibody class switching in BXD2 and control (C57BL/6) mice and high-throughput ELISA and ELISPOT analyses of synthetic peptides. Tetramers were prepared from two linear peptides derived from two RNA-binding proteins (RBPs): lupus La and 70-kDa U1 small nuclear ribonucleoprotein. Flow cytometric analysis of tetramer-reactive B cell subsets revealed a significantly higher frequency and greater numbers of RBP-reactive marginal zone precursor, transitional T3, and PDL-2(+)CD80(+) memory B cells, with significantly elevated CD69 and CD86 observed in RBP(+) marginal zone precursor B cells in the spleens of BXD2 mice compared with C57BL/6 mice, suggesting a regulatory defect. This study establishes a feasible strategy for the characterization of autoantigen-specific B cell subsets in different models of autoimmunity and, potentially, in humans.
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Affiliation(s)
- Jennie A Hamilton
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Jun Li
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Qi Wu
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294
| | - PingAr Yang
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Bao Luo
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Hao Li
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294
| | - John E Bradley
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Justin J Taylor
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109; and
| | - Troy D Randall
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294
| | - John D Mountz
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294; Department of Medicine, Birmingham, Alabama VA Medical Center, Birmingham, AL 35233
| | - Hui-Chen Hsu
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294;
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24
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Obishakin E, de Trez C, Magez S. Chronic Trypanosoma congolense infections in mice cause a sustained disruption of the B-cell homeostasis in the bone marrow and spleen. Parasite Immunol 2014; 36:187-98. [PMID: 24451010 DOI: 10.1111/pim.12099] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/15/2014] [Indexed: 12/21/2022]
Abstract
Trypanosoma congolense is one of the main species responsible for Animal African Trypanosomosis (AAT). As preventive vaccination strategies for AAT have been unsuccessful so far, investigating the mechanisms underlying vaccine failure has to be prioritized. In T. brucei and T. vivax infections, recent studies revealed a rapid onset of destruction of the host B-cell compartment, resulting in the loss of memory recall capacity. To assess such effect in experimental T. congolense trypanosomosis, we performed infections with both the cloned Tc13 parasite, which is considered as a standard model system for T. congolense rodent infections and the noncloned TRT55 field isolate. These infections differ in their virulence level in the C57BL/6 mouse model for trypanosomosis. We show that early on, an irreversible depletion of all developmental B cells stages occur. Subsequently, in the spleen, a detrimental decrease in immature B cells is followed by a significant and permanent depletion of Marginal zone B cells and Follicular B cells. The severity of these events later on in infection correlated with the virulence level of the parasite stock. In line with this, it was observed that later-stage infection-induced IgGs were largely nonspecific, in particular in the more virulent TRT55 infection model.
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Affiliation(s)
- E Obishakin
- Laboratory for Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium; Department of Structural Biology, VIB, Brussels, Belgium
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25
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Ikebuchi R, Konnai S, Okagawa T, Nishimori A, Nakahara A, Murata S, Ohashi K. Differences in cellular function and viral protein expression between IgMhigh and IgMlow B-cells in bovine leukemia virus-infected cattle. J Gen Virol 2014; 95:1832-1842. [PMID: 24814926 DOI: 10.1099/vir.0.065011-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Bovine leukemia virus (BLV) induces abnormal B-cell proliferation and B-cell lymphoma in cattle, where the BLV provirus is integrated into the host genome. BLV-infected B-cells rarely express viral proteins in vivo, but short-term cultivation augments BLV expression in some, but not all, BLV-infected B-cells. This observation suggests that two subsets, i.e. BLV-silencing cells and BLV-expressing cells, are present among BLV-infected B-cells, although the mechanisms of viral expression have not been determined. In this study, we examined B-cell markers and viral antigen expression in B-cells from BLV-infected cattle to identify markers that may discriminate BLV-expressing cells from BLV-silencing cells. The proportions of IgM(high) B-cells were increased in blood lymphocytes from BLV-infected cattle. IgM(high) B-cells mainly expressed BLV antigens, whereas IgM(low) B-cells did not, although the provirus load was equivalent in both subsets. Several parameters were investigated in these two subsets to characterize their cellular behaviour. Real-time PCR and microarray analyses detected higher expression levels of some proto-oncogenes (e.g. Maf, Jun and Fos) in IgM(low) B-cells than those in IgM(high) B-cells. Moreover, lymphoma cells obtained from the lymph nodes of 14 BLV-infected cattle contained IgM(low) or IgM(-) B-cells but no IgM(high) B-cells. To our knowledge, this is the first study to demonstrate that IgM(high) B-cells mainly comprise BLV-expressing cells, whereas IgM(low) B-cells comprise a high proportion of BLV-silencing B-cells in BLV-infected cattle.
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Affiliation(s)
- Ryoyo Ikebuchi
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Satoru Konnai
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Tomohiro Okagawa
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Asami Nishimori
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Ayako Nakahara
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Shiro Murata
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kazuhiko Ohashi
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
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26
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Sanz I. Rationale for B cell targeting in SLE. Semin Immunopathol 2014; 36:365-75. [PMID: 24763533 DOI: 10.1007/s00281-014-0430-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 04/01/2014] [Indexed: 01/16/2023]
Abstract
B cells are central pathogenic players in systemic lupus erythematosus and multiple other autoimmune diseases through antibody production as well as antibody independent function. At the same time, B cells are known to play important regulatory functions that may protect against autoimmune manifestations. Yet, the functional role of different B cell populations and their contribution to disease remain to be understood. The advent of agents that specifically target B cells, in particular anti-CD20 and ant-BLyS antibodies, have demonstrated the efficacy of this approach for the treatment of human autoimmunity. The analysis of patients treated with these and other B cell agents provides a unique opportunity to understand the correlates of clinical response and the significance of different B cell subsets. Here, we discuss this information and how it could be used to better understand SLE and improve the rational design of B cell-directed therapies in this disease.
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Affiliation(s)
- Iñaki Sanz
- Division of Rheumatology, Lowance Center for Human Immunology, Georgia Research Alliance Eminent Scholar in Human Immunology, 247 Whitehead Research Bldg. 615 Michael St., Atlanta, GA, 30322, USA,
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Zikherman J, Parameswaran R, Weiss A. Endogenous antigen tunes the responsiveness of naive B cells but not T cells. Nature 2012; 489:160-4. [PMID: 22902503 PMCID: PMC3438375 DOI: 10.1038/nature11311] [Citation(s) in RCA: 233] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 06/11/2012] [Indexed: 01/17/2023]
Abstract
In humans, up to 75% of newly generated B cells and about 30% of mature B cells show some degree of autoreactivity. Yet, how B cells establish and maintain tolerance in the face of autoantigen exposure during and after development is not certain. Studies of model B-cell antigen receptor (BCR) transgenic systems have highlighted the critical role of functional unresponsiveness or ‘anergy’. Unlike T cells, evidence suggests that receptor editing and anergy, rather than deletion, account for much of B-cell tolerance. However, it remains unclear whether the mature diverse B-cell repertoire of mice contains anergic autoreactive B cells, and if so, whether antigen was encountered during or after their development. By taking advantage of a reporter mouse in which BCR signalling rapidly and robustly induces green fluorescent protein expression under the control of the Nur77 regulatory region, antigen-dependent and antigen-independent BCR signalling events in vivo during B-cell maturation were visualized. Here we show that B cells encounter antigen during development in the spleen, and that this antigen exposure, in turn, tunes the responsiveness of BCR signalling in B cells at least partly by downmodulating expression of surface IgM but not IgD BCRs, and by modifying basal calcium levels. By contrast, no analogous process occurs in naive mature T cells. Our data demonstrate not only that autoreactive B cells persist in the mature repertoire, but that functional unresponsiveness or anergy exists in the mature B-cell repertoire along a continuum, a fact that has long been suspected, but never yet shown. These results have important implications for understanding how tolerance in T and B cells is differently imposed, and how these processes might go awry in disease.
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Affiliation(s)
- Julie Zikherman
- Division of Rheumatology, Department of Medicine, Rosalind Russell Medical Research Center for Arthritis, University of California, San Francisco, California 94143, USA
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28
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Getahun A, Smith MJ, Kogut I, van Dyk LF, Cambier JC. Retention of anergy and inhibition of antibody responses during acute γ herpesvirus 68 infection. THE JOURNAL OF IMMUNOLOGY 2012; 189:2965-74. [PMID: 22904300 DOI: 10.4049/jimmunol.1201407] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The majority of the human population becomes infected early in life by the gammaherpesvirus EBV. Some findings suggest that there is an association between EBV infection and the appearance of pathogenic Abs found in lupus. Gammaherpesvirus 68 infection of adult mice (an EBV model) was shown to induce polyclonal B cell activation and hypergammaglobulinemia, as well as increased production of autoantibodies. In this study, we explored the possibility that this breach of tolerance reflects loss of B cell anergy. Our findings show that, although anergic B cells transiently acquire an activated phenotype early during infection, they do not become responsive to autoantigen, as measured by the ability to mobilize Ca2+ following AgR cross-linking or mount Ab responses following immunization. Indeed, naive B cells also acquire an activated phenotype during acute infection but are unable to mount Ab responses to either T cell-dependent or T cell-independent Ags. In acutely infected animals, Ag stimulation leads to upregulation of costimulatory molecules and relocalization of Ag-specific B cells to the B-T cell border; however, these cells do not proliferate or differentiate into Ab-secreting cells. Adoptive-transfer experiments show that the suppressed state is reversible and is dictated by the environment in the infected host. Finally, B cells in infected mice deficient of CD4+ T cells are not suppressed, suggesting a role for CD4+ T cells in enforcing unresponsiveness. Thus, rather than promoting loss of tolerance, gammaherpesvirus 68 infection induces an immunosuppressed state, reminiscent of compensatory anti-inflammatory response syndrome.
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Affiliation(s)
- Andrew Getahun
- Integrated Department of Immunology, University of Colorado School of Medicine and National Jewish Health, Denver, CO 80206, USA
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29
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Ledesma-Soto Y, Blanco-Favela F, Fuentes-Pananá EM, Tesoro-Cruz E, Hernández-González R, Arriaga-Pizano L, Legorreta-Haquet MV, Montoya-Diaz E, Chávez-Sánchez L, Castro-Mussot ME, Chávez-Rueda AK. Increased levels of prolactin receptor expression correlate with the early onset of lupus symptoms and increased numbers of transitional-1 B cells after prolactin treatment. BMC Immunol 2012; 13:11. [PMID: 22404893 PMCID: PMC3353839 DOI: 10.1186/1471-2172-13-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 03/09/2012] [Indexed: 11/10/2022] Open
Abstract
Background Prolactin is secreted from the pituitary gland and other organs, as well as by cells such as lymphocytes. Prolactin has an immunostimulatory effect and is associated with autoimmune diseases that are characterised by abnormal B cell activation, such as systemic lupus erythematosus (SLE). Our aim was to determine if different splenic B cell subsets express the prolactin receptor and if the presence of prolactin influences these B cell subsets and correlates with development of lupus. Results Using real-time PCR and flow cytometry, we found that different subsets of immature (transitional) and mature (follicular, marginal zone) B cells express different levels of the prolactin receptor and are differentially affected by hyperprolactinaemia. We found that transitional B cells express the prolactin receptor at higher levels compared to mature B cells in C57BL/6 mice and the lupus-prone MRL/lpr and MRL mouse strains. Transitional-1 (T1) B cells showed a higher level of prolactin receptor expression in both MRL/lpr and MRL mice compared to C57BL/6 mice. Hyperprolactinaemia was induced using metoclopramide, which resulted in the development of early symptoms of SLE. We found that T1 B cells are the main targets of prolactin and that prolactin augments the absolute number of T1 B cells, which reflects the finding that this B cell subpopulation expresses the highest level of the prolactin receptor. Conclusions We found that all B cell subsets express the prolactin receptor but that transitional B cells showed the highest prolactin receptor expression levels. Hyperprolactinaemia in mice susceptible to lupus accelerated the disease and increased the absolute numbers of T1 and T3 B cells but not of mature B cells, suggesting a primary effect of prolactin on the early stages of B cell maturation in the spleen and a role of prolactin in B cell differentiation, contributing to SLE onset.
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Affiliation(s)
- Yadira Ledesma-Soto
- Unidad de Investigación Médica en Inmunología, Hospital de Pediatría, CMN Siglo XXI, IMSS, Av Cuauhtemoc 330, Col. Doctores, Mexico, D.F. CP06720, Mexico
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Vossenkämper A, Lutalo PMK, Spencer J. Translational Mini-Review Series on B cell subsets in disease. Transitional B cells in systemic lupus erythematosus and Sjögren's syndrome: clinical implications and effects of B cell-targeted therapies. Clin Exp Immunol 2012; 167:7-14. [PMID: 22132879 PMCID: PMC3248081 DOI: 10.1111/j.1365-2249.2011.04460.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2011] [Indexed: 12/11/2022] Open
Abstract
Systemic lupus erythematosus (SLE) and Sjögren's syndrome are autoimmune disorders which are characterized by a disturbed B cell homeostasis which leads ultimately to dysfunction of various organs. One of the B cell subsets that appear in abnormal numbers is the population of transitional B cells, which is increased in the blood of patients with SLE and Sjögren's syndrome. Transitional B cells are newly formed B cells. In mice, transitional B cells undergo selection checks for unwanted specificity in the bone marrow and the spleen in order to eliminate autoreactive B cells from the circulating naive B cell population. In humans, the exact anatomical compartments and mechanisms of the specificity check-points for transitional B cells remain unclear, but appear to be defective in SLE and Sjögren's syndrome. This review aims to highlight the current understanding of transitional B cells and their defects in the two disorders before and after B cell-targeted therapies.
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MESH Headings
- Animals
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Monoclonal, Humanized/therapeutic use
- Antibodies, Monoclonal, Murine-Derived/therapeutic use
- B-Cell Activating Factor/immunology
- B-Lymphocyte Subsets/immunology
- B-Lymphocyte Subsets/pathology
- Clinical Trials, Phase II as Topic
- Clinical Trials, Phase III as Topic
- Disease Models, Animal
- Double-Blind Method
- Humans
- Lupus Erythematosus, Systemic/immunology
- Lupus Erythematosus, Systemic/pathology
- Lupus Erythematosus, Systemic/therapy
- Lymphocyte Count
- Lymphocyte Depletion/methods
- Lymphoid Tissue/immunology
- Lymphoid Tissue/pathology
- Lymphopoiesis
- Mice
- Rituximab
- Sjogren's Syndrome/immunology
- Sjogren's Syndrome/pathology
- Sjogren's Syndrome/therapy
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Affiliation(s)
- A Vossenkämper
- Centre for Immunology and Infectious Disease, Barts and The London School of Medicine and Dentistry, Blizard Institute, London, UK.
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31
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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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32
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Vossenkämper A, Spencer J. Transitional B cells: how well are the checkpoints for specificity understood? Arch Immunol Ther Exp (Warsz) 2011; 59:379-84. [PMID: 21789626 DOI: 10.1007/s00005-011-0135-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 04/26/2011] [Indexed: 12/18/2022]
Abstract
It is crucial for the immune system to minimise the number of circulating mature self-reactive B cells, in order to reduce the potential for the development of autoantibody-related autoimmune diseases. Studies of animal models have identified two major checkpoints that ensure that such cells do not contribute to the naïve B cell repertoire. The first is in the bone marrow as B cells develop and the second is in the spleen; B cells that are released from the bone marrow as transitional B cells go through more stringent selection in the spleen before they develop into mature naïve B cells. Transitional B cells and their maturation have mostly been studied in mice. However, recent studies characterised human transitional B cells and found considerable differences to current models. In this review, we will consider these differences alongside known differences in mouse and human splenic function and ask whether human transitional B cells might develop along a different pathway.
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Affiliation(s)
- Anna Vossenkämper
- Centre for Immunology and Infectious Disease, Barts and The London School of Medicine and Dentistry, Blizard Institute, UK.
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33
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Bockstal V, Guirnalda P, Caljon G, Goenka R, Telfer JC, Frenkel D, Radwanska M, Magez S, Black SJ. T. brucei infection reduces B lymphopoiesis in bone marrow and truncates compensatory splenic lymphopoiesis through transitional B-cell apoptosis. PLoS Pathog 2011; 7:e1002089. [PMID: 21738467 PMCID: PMC3128123 DOI: 10.1371/journal.ppat.1002089] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 04/12/2011] [Indexed: 12/31/2022] Open
Abstract
African trypanosomes of the Trypanosoma brucei species are extracellular protozoan parasites that cause the deadly disease African trypanosomiasis in humans and contribute to the animal counterpart, Nagana. Trypanosome clearance from the bloodstream is mediated by antibodies specific for their Variant Surface Glycoprotein (VSG) coat antigens. However, T. brucei infection induces polyclonal B cell activation, B cell clonal exhaustion, sustained depletion of mature splenic Marginal Zone B (MZB) and Follicular B (FoB) cells, and destruction of the B-cell memory compartment. To determine how trypanosome infection compromises the humoral immune defense system we used a C57BL/6 T. brucei AnTat 1.1 mouse model and multicolor flow cytometry to document B cell development and maturation during infection. Our results show a more than 95% reduction in B cell precursor numbers from the CLP, pre-pro-B, pro-B, pre-B and immature B cell stages in the bone marrow. In the spleen, T. brucei induces extramedullary B lymphopoiesis as evidenced by significant increases in HSC-LMPP, CLP, pre-pro-B, pro-B and pre-B cell populations. However, final B cell maturation is abrogated by infection-induced apoptosis of transitional B cells of both the T1 and T2 populations which is not uniquely dependent on TNF-, Fas-, or prostaglandin-dependent death pathways. Results obtained from ex vivo co-cultures of living bloodstream form trypanosomes and splenocytes demonstrate that trypanosome surface coat-dependent contact with T1/2 B cells triggers their deletion. We conclude that infection-induced and possibly parasite-contact dependent deletion of transitional B cells prevents replenishment of mature B cell compartments during infection thus contributing to a loss of the host's capacity to sustain antibody responses against recurring parasitemic waves. African trypanosomiasis caused by Trypanosoma brucei species is fatal in both humans and animals and cannot be combated by vaccination because of extensive parasite antigenic variation. Effective trypanosome control and clearance from the bloodstream involves the action of antibodies specific for the parasite's highly diverse variable surface glycoprotein antigens. However, experimental infections in mice have shown that trypanosomiasis elicits a rapid process of B cell exhaustion and loss of protective antibody responses. Indeed, both marginal zone B cells, the first line of defense against blood-borne pathogens like T. brucei parasites, and follicular B cells, which are the major source for developing high-affinity antibody-producing plasma cells and memory B cells, become depleted during infection. In addition, existing B-cell memory, both against parasite antigens and non related pathogens, is destroyed early on in infection. Here, we demonstrate that during infection, B cell development is decreased in the bone marrow and early B cell development is taken over by the spleen. However, full maturation of developing B cells is abrogated by the occurrence of transitional B cell apoptosis. This impairs the replenishment of the mature marginal zone and follicular B cell pools and prevents the buildup of protective immunity against successive parasitemic waves.
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Affiliation(s)
- Viki Bockstal
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts, United States of America
- Laboratory for Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Molecular and Cellular Interactions, VIB, Brussels, Belgium
| | - Patrick Guirnalda
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Guy Caljon
- Laboratory for Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Molecular and Cellular Interactions, VIB, Brussels, Belgium
- Unit of Veterinary Protozoology, Institute of Tropical Medicine, Antwerp, Belgium
| | - Radhika Goenka
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Janice C. Telfer
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Deborah Frenkel
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts, United States of America
| | | | - Stefan Magez
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts, United States of America
- Laboratory for Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Molecular and Cellular Interactions, VIB, Brussels, Belgium
- * E-mail: (SJB); (SM)
| | - Samuel J. Black
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts, United States of America
- * E-mail: (SJB); (SM)
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Abstract
A byproduct of the largely stochastic generation of a diverse B-cell specificity repertoire is production of cells that recognize autoantigens. Indeed, recent studies indicate that more than half of the primary repertoire consists of autoreactive B cells that must be silenced to prevent autoimmunity. While this silencing can occur by multiple mechanisms, it appears that most autoreactive B cells are silenced by anergy, wherein they populate peripheral lymphoid organs and continue to express unoccupied antigen receptors yet are unresponsive to antigen stimulation. Here we review molecular mechanisms that appear operative in maintaining the antigen unresponsiveness of anergic B cells. In addition, we present new data indicating that the failure of anergic B cells to mobilize calcium in response to antigen stimulation is not mediated by inactivation of stromal interacting molecule 1, a critical intermediary in intracellular store depletion-induced calcium influx.
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Affiliation(s)
- Yuval Yarkoni
- Integrated Department of Immunology, University of Colorado School of Medicine and National Jewish Health, Denver, CO, USA
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35
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Giltiay NV, Lu Y, Allman D, Jørgensen TN, Li X. The adaptor molecule Act1 regulates BAFF responsiveness and self-reactive B cell selection during transitional B cell maturation. THE JOURNAL OF IMMUNOLOGY 2010; 185:99-109. [PMID: 20543113 DOI: 10.4049/jimmunol.0903312] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The transitional stage is a key check-point for elimination of autoreactive B cells in the periphery. This selection process requires fine regulation of signals received through BCR and B cell activating factor (BAFF) receptor. We previously identified the adaptor molecule Act1 as a negative regulator of BAFF-mediated signaling. Deficiency of Act1 in mice results in peripheral B cell hyperplasia and development of autoimmunity. In this study, we demonstrate that Act1 plays a critical role in the regulation of transitional B cell survival and maturation. We found that the ratio of late-transitional (T2) to early-transitional (T1) cells was increased in spleens from Act1-deficient mice. Moreover, BAFF stimulation induced better T1 cell survival and promoted more efficient maturation of T1 cells into T2 cells ex vivo in the absence of Act1. BAFF stimulation induced higher levels of the anti-apoptotic Bcl-2 member Mc1-l in Act1-deficient T1 cells than in wild-type control cells, suggesting that Mcl-1 might be one of the key effector molecules for BAFF-mediated survival of the Act1-deficient transitional B cells. Importantly, costimulation with BAFF was able to rescue Act1-deficient T1 cells from BCR-induced apoptosis more effectively than Act1-sufficient T1 B cells. Finally, by using hen egg lysozyme double transgenic mice, we demonstrated that Act1 deficiency can promote the maturation of Ag-specific autoreactive B cells. Taken together, our results suggest that the transitional stage is a critical point of action of Act1 in the elimination of autoreactive B cells and in the regulation of peripheral B cell homeostasis.
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Affiliation(s)
- Natalia V Giltiay
- Department of Immunology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
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36
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Kat I, Makdasi E, Fischel R, Eilat D. B-cell anergy is maintained in anti-DNA transgenic NZB/NZW mice. Int Immunol 2009; 22:101-11. [PMID: 20038519 DOI: 10.1093/intimm/dxp120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Clonal anergy has been well recognized as an important mechanism of B cell immunologic tolerance. However, the properties of anergic B cells and especially their role in the development of autoimmune disease in susceptible animals have been controversial. Here we show that low-affinity anti-DNA anergic B cells populate the mature B-cell compartment in the mouse spleen in excessive numbers and display paradoxical behavior in response to a combined B-cell receptor/TLR9 activation. Surprisingly, B-cell anergy was maintained in aged NZB/NZW F1 mice that develop a systemic lupus erythematosus (SLE)-like autoimmune disease. In several parameters of anergy, such as calcium mobilization and antibody secretion, the lupus-prone mice appeared more anergic than their non-autoimmune counterparts. We conclude that low-affinity anergic B cells are unlikely to serve as precursors for the high-affinity autoreactive B cells that give rise to pathogenic anti-DNA auto-antibodies in SLE.
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Affiliation(s)
- Inbal Kat
- Department of Medicine, Hadassah University Hospital, The Hebrew University Faculty of Medicine, Jerusalem 91120, Israel
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37
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Differential expression of CD21 identifies developmentally and functionally distinct subsets of human transitional B cells. Blood 2009; 115:519-29. [PMID: 19965666 DOI: 10.1182/blood-2009-07-234799] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The transitional stage of B-cell development represents an important step where autoreactive cells are deleted, allowing the generation of a mature functional B-cell repertoire. In mice, 3 subsets of transitional B cells have been identified. In contrast, most studies of human transitional B cells have focused on a single subset defined as CD24(hi)CD38(hi) B cells. Here, we have identified 2 subsets of human transitional B cells based on the differential expression of CD21. CD21(hi) transitional cells displayed higher expression of CD23, CD44, and IgD, and exhibited greater proliferation and Ig secretion in vitro than CD21(lo) transitional B cells. In contrast, the CD21(lo) subset expressed elevated levels of LEF1, a transcription factor highly expressed by immature lymphocytes, and produced higher amounts of autoreactive Ab. These phenotypic, functional, and molecular features suggest that CD21(lo) transitional B cells are less mature than the CD21(hi) subset. This was confirmed by analyzing X-linked agammaglobulinemia patients and the kinetics of B-cell reconstitution after stem cell transplantation, which revealed that the development of CD21(lo) transitional B cells preceded that of CD21(hi) transitional cells. These findings provide important insights into the process of human B-cell development and have implications for understanding the processes underlying perturbed B-cell maturation in autoimmune and immunodeficient conditions.
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Getahun A, O’Neill SK, Cambier JC. Establishing anergy as a bona fide in vivo mechanism of B cell tolerance. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2009; 183:5439-41. [PMID: 19843930 PMCID: PMC2968702 DOI: 10.4049/jimmunol.0990088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
| | | | - John C. Cambier
- Address correspondence and reprint requests to Dr. John C. Cambier, 1400 Jackson Street, K803, Denver, CO 80206.
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Abstract
The tumour necrosis factor (TNF) family members B cell activating factor (BAFF) and APRIL (a proliferation-inducing ligand) are crucial survival factors for peripheral B cells. An excess of BAFF leads to the development of autoimmune disorders in animal models, and high levels of BAFF have been detected in the serum of patients with various autoimmune conditions. In this Review, we consider the possibility that in mice autoimmunity induced by BAFF is linked to T cell-independent B cell activation rather than to a severe breakdown of B cell tolerance. We also outline the mechanisms of BAFF signalling, the impact of ligand oligomerization on receptor activation and the progress of BAFF-depleting agents in the clinical setting.
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Saha S, Gonzalez J, Rosenfeld G, Keiser H, Peeva E. Prolactin alters the mechanisms of B cell tolerance induction. ARTHRITIS AND RHEUMATISM 2009; 60:1743-52. [PMID: 19479826 PMCID: PMC2733916 DOI: 10.1002/art.24500] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE Autoimmune diseases predominantly affect women, suggesting that female sex hormones may play a role in the pathogenesis of such diseases. We have previously shown that persistent mild-to-moderate elevations in serum prolactin levels induce a break in self tolerance in mice with a BALB/c genetic background. The aim of this study was to evaluate the effects of hyperprolactinemia on the mechanisms of B cell tolerance induction. METHODS Effects of prolactin on splenic B cell subsets were studied in female BALB/c mice. B cell receptor (BCR)-mediated apoptosis and proliferation of transitional B cells were analyzed by flow cytometry. Expression of apoptotic genes was examined by microarrays and real-time polymerase chain reaction analysis. B cells coexpressing kappa/lambda light chains were assessed by flow cytometry and immunohistochemistry. Activation status of transitional type 3 (T3) B cells was evaluated by BCR-induced calcium influx studies. RESULTS BCR-mediated apoptosis of the T1 B cell subset, a major checkpoint for negative selection of autoreactive specificities, was decreased in prolactin-treated mice. Microarray studies indicated that this event may be mediated by the prolactin-induced up-regulation of the antiapoptotic gene interferon-gamma receptor type II and down-regulation of the proapoptotic gene Trp63. Prolactin treatment also altered the amount of receptor editing, as indicated by the increased number of transitional B cells coexpressing kappa/lambda light chains. Additionally, hyperprolactinemia modified the level of B cell anergy by increasing the degree of BCR-induced calcium influx in the T3 B cells. CONCLUSION Persistently elevated serum prolactin levels interfere with B cell tolerance induction by impairing BCR-mediated clonal deletion, deregulating receptor editing, and decreasing the threshold for activation of anergic B cells, thereby promoting autoreactivity.
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Affiliation(s)
- Subhrajit Saha
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Juana Gonzalez
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Gabriel Rosenfeld
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Harold Keiser
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Elena Peeva
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
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Mayne CG, Nashold FE, Sasaki Y, Hayes CE. Altered BAFF-receptor signaling and additional modifier loci contribute to systemic autoimmunity in A/WySnJ mice. Eur J Immunol 2009; 39:589-99. [PMID: 19152335 DOI: 10.1002/eji.200838569] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Systemic lupus erythematosus pathology reflects autoantibody-mediated damage due to a failure of B-lymphocyte tolerance. We previously reported that B-lymphopenic A/WySnJ mice develop a lupus-like syndrome and linked this syndrome to the B-cell maturation defect-1 (Bcmd-1) mutant allele of the B-cell-activating factor belonging to the TNF family-receptor (Baffr) gene. Here, we further evaluate the genetic basis for autoimmunity in A/WySnJ mice. We produced B6.Bcmd-1 and AW.Baffr(-/-) congenic mice (N5), and compared them with B6.Baffr(-/-) and A/WySnJ mice with respect to B-lymphocyte development. Bcmd-1-expressing mice had more B cells with greater maturity than Baffr(-/-) mice regardless of genetic background, indicating that Bcmd-1 encodes a partially functional BAFF-R. We also compared these mice for lupus phenotypes to determine whether Bcmd-1 is necessary and sufficient for disease, or whether the Baffr(-/-) (-) allele can also cause autoimmunity. The Baffr(-/-) allele did not lead to autoimmunity on either genetic background. In contrast, the Bcmd-1 allele was necessary and sufficient for development of low levels of IgM autoantibodies in B6.Bcmd-1 mice. However, Bcmd-1 plus unidentified A/WySnJ modifier genes were necessary for development of IgG autoantibodies and renal pathology. We propose that in A/WySnJ mice an excess of BAFF per B cell rescues self-reactive B cells through a partially functional BAFF-R in a B-lymphopenic environment.
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Signalling of the BCR is regulated by a lipid rafts-localised transcription factor, Bright. EMBO J 2009; 28:711-24. [PMID: 19214191 DOI: 10.1038/emboj.2009.20] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 01/09/2009] [Indexed: 02/06/2023] Open
Abstract
Regulation of BCR signalling strength is crucial for B-cell development and function. Bright is a B-cell-restricted factor that complexes with Bruton's tyrosine kinase (Btk) and its substrate, transcription initiation factor-I (TFII-I), to activate immunoglobulin heavy chain gene transcription in the nucleus. Here we show that a palmitoylated pool of Bright is diverted to lipid rafts of resting B cells where it associates with signalosome components. After BCR ligation, Bright transiently interacts with sumoylation enzymes, blocks calcium flux and phosphorylation of Btk and TFII-I and is then discharged from lipid rafts as a Sumo-I-modified form. The resulting lipid raft concentration of Bright contributes to the signalling threshold of B cells, as their sensitivity to BCR stimulation decreases as the levels of Bright increase. Bright regulates signalling independent of its role in IgH transcription, as shown by specific dominant-negative titration of rafts-specific forms. This study identifies a BCR tuning mechanism in lipid rafts that is regulated by differential post-translational modification of a transcription factor with implications for B-cell tolerance and autoimmunity.
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Duty JA, Szodoray P, Zheng NY, Koelsch KA, Zhang Q, Swiatkowski M, Mathias M, Garman L, Helms C, Nakken B, Smith K, Farris AD, Wilson PC. Functional anergy in a subpopulation of naive B cells from healthy humans that express autoreactive immunoglobulin receptors. ACTA ACUST UNITED AC 2008; 206:139-51. [PMID: 19103878 PMCID: PMC2626668 DOI: 10.1084/jem.20080611] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Self-reactive B cells not controlled by receptor editing or clonal deletion may become anergic. We report that fully mature human B cells negative for surface IgM and retaining only IgD are autoreactive and functionally attenuated (referred to as naive IgD+IgM− B cells [BND]). These BND cells typically make up 2.5% of B cells in the peripheral blood, have antibody variable region genes in germline (unmutated) configuration, and, by all current measures, are fully mature. Analysis of 95 recombinant antibodies expressed from the variable genes of single BND cells demonstrated that they are predominantly autoreactive, binding to HEp-2 cell antigens and DNA. Upon B cell receptor cross-linkage, BND cells have a reduced capacity to mobilize intracellular calcium or phosphorylate tyrosines, demonstrating that they are anergic. However, intense stimulation causes BND cells to fully respond, suggesting that these cells could be the precursors of autoantibody secreting plasma cells in autoimmune diseases such as systemic lupus erythematosus or rheumatoid arthritis. This is the first identification of a distinct mature human B cell subset that is naturally autoreactive and controlled by the tolerizing mechanism of functional anergy.
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Affiliation(s)
- J Andrew Duty
- Immunobiology and Cancer, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
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Abstract
Systemic autoimmunity such as systemic lupus erythematosus (SLE) is associated with the loss of B-cell tolerance, B-cell dysregulation and autoantibody production. While some autoantibodies may contribute to the pathology seen with SLE, numerous studies have shown that dysregulation of T-cell function is another critical aspect driving disease. The positive results obtained in clinical trials using T-cell- or B-cell-specific treatments have suggested that cooperation between T and B cells probably underlies disease progression in many patients. A similar cooperative mechanism seemed to explain SLE developing in mice overexpressing the B-cell-activating factor from the tumor necrosis factor family (BAFF). However, surprisingly, T-cell-deficient BAFF transgenic (Tg) mice develop SLE similar to T-cell-sufficient BAFF Tg mice, and the disease was linked to innate activation of B cells and production of proinflammatory autoantibody isotypes. In conclusion, dysregulated innate activation of B cells alone can drive disease independently of T cells, and as such this aspect represents a new pathogenic mechanism in autoimmunity.
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Carey JB, Moffatt-Blue CS, Watson LC, Gavin AL, Feeney AJ. Repertoire-based selection into the marginal zone compartment during B cell development. ACTA ACUST UNITED AC 2008; 205:2043-52. [PMID: 18710933 PMCID: PMC2526199 DOI: 10.1084/jem.20080559] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Marginal zone (MZ) B cells resemble fetally derived B1 B cells in their innate-like rapid responses to bacterial pathogens, but the basis for this is unknown. We report that the MZ is enriched in “fetal-type” B cell receptors lacking N regions (N−). Mixed bone marrow (BM) chimeras, made with adult terminal deoxynucleotidyl transferase (TdT)+/+ and TdT−/− donor cells, demonstrate preferential repertoire-based selection of N− B cells into the MZ. Reconstitution of irradiated mice with adult TdT+/+ BM reveals that the MZ can replenish N− B cells in adult life via repertoire-based selection and suggest the possibility of a TdT-deficient precursor population in the adult BM. The mixed chimera data also suggest repertoire-based bifurcations into distinct BM and splenic maturation pathways, with mature “recirculating” BM B cells showing a very strong preference for N+ complementarity-determining region (CDR) 3 compared with follicular B cells. Because the T1 and MZ compartments are both the most enriched for N− H-CDR3, we propose a novel direct T1→MZ pathway and identify a potential T1–MZ precursor intermediate. We demonstrate progressive but discontinuous repertoire-based selection throughout B cell development supporting multiple branchpoints and pathways in B cell development. Multiple differentiation routes leading to MZ development may contribute to the reported functional heterogeneity of the MZ compartment.
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Affiliation(s)
- John B Carey
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA
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Kiefer K, Nakajima PB, Oshinsky J, Seeholzer SH, Radic M, Bosma GC, Bosma MJ. Antigen receptor editing in anti-DNA transitional B cells deficient for surface IgM. THE JOURNAL OF IMMUNOLOGY 2008; 180:6094-106. [PMID: 18424731 DOI: 10.4049/jimmunol.180.9.6094] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In response to encounter with self-Ag, autoreactive B cells may undergo secondary L chain gene rearrangement (receptor editing) and change the specificity of their Ag receptor. Knowing at what differentiative stage(s) developing B cells undergo receptor editing is important for understanding how self-reactive B cells are regulated. In this study, in mice with Ig transgenes coding for anti-self (DNA) Ab, we report dsDNA breaks indicative of ongoing secondary L chain rearrangement not only in bone marrow cells with a pre-B/B cell phenotype but also in immature/transitional splenic B cells with little or no surface IgM (sIgM(-/low)). L chain-edited transgenic B cells were detectable in spleen but not bone marrow and were still found to produce Ab specific for DNA (and apoptotic cells), albeit with lower affinity for DNA than the unedited transgenic Ab. We conclude that L chain editing in anti-DNA-transgenic B cells is not only ongoing in bone marrow but also in spleen. Indeed, transfer of sIgM(-/low) anti-DNA splenic B cells into SCID mice resulted in the appearance of a L chain editor (Vlambdax) in the serum of engrafted recipients. Finally, we also report evidence for ongoing L chain editing in sIgM(low) transitional splenic B cells of wild-type mice.
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Affiliation(s)
- Kerstin Kiefer
- Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
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Cambier JC, Gauld SB, Merrell KT, Vilen BJ. B-cell anergy: from transgenic models to naturally occurring anergic B cells? Nat Rev Immunol 2007; 7:633-43. [PMID: 17641666 PMCID: PMC3714009 DOI: 10.1038/nri2133] [Citation(s) in RCA: 254] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Anergy, a condition in which cells persist in the periphery but are unresponsive to antigen, is responsible for silencing many self-reactive B cells. Loss of anergy is known to contribute to the development of autoimmune diseases, including systemic lupus erythematosus and type 1 diabetes. Multiple transgenic mouse models have enabled the dissection of mechanisms that underlie anergy, and recently, anergic B cells have been identified in the periphery of wild-type mice. Heterogeneity of mechanistic concepts developed using model systems has complicated our understanding of anergy and its biological features. In this Review, we compare and contrast the salient features of anergic B cells with a view to developing unifying mechanistic hypotheses that explain their lifestyles.
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Affiliation(s)
- John C Cambier
- Department of Immunology, University of Colorado Health Science Center and National Jewish Medical Research Center, 1400 Jackson Street, Denver, Colorado 80206, USA.
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