1
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Ng TW, Furuyama W, Wirchnianski AS, Saavedra-Ávila NA, Johndrow CT, Chandran K, Jacobs WR, Marzi A, Porcelli SA. A viral vaccine design harnessing prior BCG immunization confers protection against Ebola virus. Front Immunol 2024; 15:1429909. [PMID: 39081315 PMCID: PMC11286471 DOI: 10.3389/fimmu.2024.1429909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Accepted: 06/25/2024] [Indexed: 08/02/2024] Open
Abstract
Previous studies have demonstrated the efficacy and feasibility of an anti-viral vaccine strategy that takes advantage of pre-existing CD4+ helper T (Th) cells induced by Mycobacterium bovis bacille Calmette-Guérin (BCG) vaccination. This strategy uses immunization with recombinant fusion proteins comprised of a cell surface expressed viral antigen, such as a viral envelope glycoprotein, engineered to contain well-defined BCG Th cell epitopes, thus rapidly recruiting Th cells induced by prior BCG vaccination to provide intrastructural help to virus-specific B cells. In the current study, we show that Th cells induced by BCG were localized predominantly outside of germinal centers and promoted antibody class switching to isotypes characterized by strong Fc receptor interactions and effector functions. Furthermore, BCG vaccination also upregulated FcγR expression to potentially maximize antibody-dependent effector activities. Using a mouse model of Ebola virus (EBOV) infection, this vaccine strategy provided sustained antibody levels with strong IgG2c bias and protection against lethal challenge. This general approach can be easily adapted to other viruses, and may be a rapid and effective method of immunization against emerging pandemics in populations that routinely receive BCG vaccination.
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Affiliation(s)
- Tony W. Ng
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Wakako Furuyama
- Laboratory of Virology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institute of Health, Hamilton, MT, United States
| | - Ariel S. Wirchnianski
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Noemí A. Saavedra-Ávila
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Christopher T. Johndrow
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - William R. Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Andrea Marzi
- Laboratory of Virology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institute of Health, Hamilton, MT, United States
| | - Steven A. Porcelli
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, United States
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2
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Ng TW, Furuyama W, Wirchnianski AS, Saavedra-Ávila NA, Johndrow CT, Chandran K, Jacobs WR, Marzi A, Porcelli SA. A viral vaccine design harnessing prior BCG immunization confers protection against Ebola virus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.28.595735. [PMID: 38853867 PMCID: PMC11160617 DOI: 10.1101/2024.05.28.595735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Previous studies have demonstrated the efficacy and feasibility of an anti-viral vaccine strategy that takes advantage of pre-existing CD4 + helper T (Th) cells induced by Mycobacterium bovis bacille Calmette-Guérin (BCG) vaccination. This strategy uses immunization with recombinant fusion proteins comprised of a cell surface expressed viral antigen, such as a viral envelope glycoprotein, engineered to contain well-defined BCG Th cell epitopes, thus rapidly recruiting Th cells induced by prior BCG vaccination to provide intrastructural help to virus-specific B cells. In the current study, we show that Th cells induced by BCG were localized predominantly outside of germinal centers and promoted antibody class switching to isotypes characterized by strong Fc receptor interactions and effector functions. Furthermore, BCG vaccination also upregulated FcγR expression to potentially maximize antibody-dependent effector activities. Using a mouse model of Ebola virus (EBOV) infection, this vaccine strategy provided sustained antibody levels with strong IgG2c bias and protection against lethal challenge. This general approach can be easily adapted to other viruses, and may be a rapid and effective method of immunization against emerging pandemics in populations that routinely receive BCG vaccination.
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3
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Bhakta-Yadav MS, Burra K, Alhamdan N, Allex-Buckner CP, Sulentic CEW. The aryl hydrocarbon receptor differentially modulates the expression profile of antibody isotypes in a human B-cell line. Toxicol Sci 2024; 199:276-288. [PMID: 38526216 PMCID: PMC11131011 DOI: 10.1093/toxsci/kfae035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental contaminant and high affinity ligand for the aryl hydrocarbon receptor (AhR). In animal models, AhR activation by TCDD generally inhibits antibody secretion. However, it is less clear if this translates to human antibody production. Using a human Burkitt lymphoma B-cell line (CL-01) that can be stimulated to secrete Ig and undergo class switch recombination to other Ig isotypes, the current study evaluated the effects of AhR activation or antagonism on the human Ig isotypic expression profile with CD40L+IL-4 stimulation. Our results suggest that AhR agonists (TCDD and indirubin) have little to no effect on IgM or IgA secretion, which were also not induced with stimulation. However, AhR activation significantly inhibited stimulation-induced IgG secretion, an effect reversed by the AhR antagonist CH223191. Evaluation of Ig heavy chain (IgH) constant region gene expression (ie Cμ, Cγ1-4, Cα1-2, and Cε that encode for IgM, IgG1-4, IgA1-2, and IgE, respectively) demonstrated differential effects. While Cμ and Cα2 transcripts were unaffected by stimulation or AhR agonists, AhR activation significantly inhibited stimulation-induced Cγ2-4 and Cε mRNA transcripts, which was reversed by AhR antagonism. Notably, AhR antagonism in the absence of exogenous AhR ligands significantly increased IgG and IgA secretion as well as the expression of Cγ2-4 and Cε. These results suggest that modulation of AhR activity differentially alters the IgH isotypic expression profile and antibody secretion that may be partly dependent on cellular stimulation. Since a variety of chemicals from anthropogenic, industrial, pharmaceutical, dietary, and bacterial sources bind the AhR, the ability of environmental exposures to alter AhR activity (i.e. activate or inhibit) may have a direct influence on immune function and antibody-relevant disease conditions.
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Affiliation(s)
- Mili S Bhakta-Yadav
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio 45435, USA
| | - Kaulini Burra
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio 45435, USA
| | - Nasser Alhamdan
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio 45435, USA
| | - Clayton P Allex-Buckner
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio 45435, USA
| | - Courtney E W Sulentic
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio 45435, USA
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4
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Dézé O, Ordanoska D, Rossille D, Miglierina E, Laffleur B, Cogné M. Unique repetitive nucleic acid structures mirror switch regions in the human IgH locus. Biochimie 2023; 214:167-175. [PMID: 37678746 DOI: 10.1016/j.biochi.2023.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/29/2023] [Accepted: 08/31/2023] [Indexed: 09/09/2023]
Abstract
Immunoglobulin (Ig) genes carry the unique ability to be reshaped in peripheral B lymphocytes after these cells encounter a specific antigen. B cells can then further improve their affinity, acquire new functions as memory cells and eventually end up as antibody-secreting cells. Ig class switching is an important change that occurs in this context, thanks to local DNA lesions initiated by the enzyme activation-induced deaminase (AID). Several cis-acting elements of the Ig heavy (IgH) chain locus make it accessible to the AID-mediated lesions that promote class switch recombination (CSR). DNA repeats, with a non-template strand rich in G-quadruplexes (G4)-DNA, are prominent cis-targets of AID and define the so-called "switch" (S) regions specifically targeted for CSR. By analyzing the structure of the human IgH locus, we uncover that abundant DNA repeats, some with a putative G4-rich template strand, are additionally present in downstream portions of the IgH coding genes. These like-S (LS) regions stand as 3' mirror-images of S regions and also show analogies to some previously reported repeats associated with the IgH locus 3' super-enhancer. A regulatory role of LS repeats is strongly suggested by their specific localization close to exons encoding the membrane form of Ig molecules, and by their conservation during mammalian evolution.
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Affiliation(s)
- Ophélie Dézé
- Institut National de La Santé et de La Recherche Médicale, Unité Mixte de Recherche U1236, Université de Rennes, Etablissement Français Du Sang Bretagne, F-35000, Rennes, France
| | - Delfina Ordanoska
- Institut National de La Santé et de La Recherche Médicale, Unité Mixte de Recherche U1236, Université de Rennes, Etablissement Français Du Sang Bretagne, F-35000, Rennes, France
| | - Delphine Rossille
- Centre Hospitalier Universitaire de Rennes, SITI, Pôle Biologie, F-35033, Rennes, France
| | - Emma Miglierina
- Institut National de La Santé et de La Recherche Médicale, Unité Mixte de Recherche U1236, Université de Rennes, Etablissement Français Du Sang Bretagne, F-35000, Rennes, France
| | - Brice Laffleur
- Institut National de La Santé et de La Recherche Médicale, Unité Mixte de Recherche U1236, Université de Rennes, Etablissement Français Du Sang Bretagne, F-35000, Rennes, France
| | - Michel Cogné
- Institut National de La Santé et de La Recherche Médicale, Unité Mixte de Recherche U1236, Université de Rennes, Etablissement Français Du Sang Bretagne, F-35000, Rennes, France; Centre Hospitalier Universitaire de Rennes, SITI, Pôle Biologie, F-35033, Rennes, France.
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5
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Robinson AM, Higgins BW, Shuparski AG, Miller KB, McHeyzer-Williams LJ, McHeyzer-Williams MG. Evolution of antigen-specific follicular helper T cell transcription from effector function to memory. Sci Immunol 2022; 7:eabm2084. [PMID: 36206356 PMCID: PMC9881730 DOI: 10.1126/sciimmunol.abm2084] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Understanding how follicular helper T cells (TFH) regulate the specialization, maturation, and differentiation of adaptive B cell immunity is crucial for developing durable high-affinity immune protection. Using indexed single-cell molecular strategies, we reveal a skewed intraclonal assortment of higher-affinity T cell receptors and the distinct molecular programming of the localized TFH compartment compared with emigrant conventional effector TH cells. We find a temporal shift in B cell receptor class switch, which permits identification of inflammatory and anti-inflammatory modules of transcriptional programming that subspecialize TFH function before and during the germinal center (GC) reaction. Late collapse of this local primary GC reaction reveals a persistent post-GC TFH population that discloses a putative memory TFH program. These studies define subspecialized antigen-specific TFH transcriptional programs that progressively change with antibody class-specific evolution of high-affinity B cell immunity and a memory TFH transcriptional program that emerges upon local GC resolution.
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Dauba A, Khamlichi AA. Long-Range Control of Class Switch Recombination by Transcriptional Regulatory Elements. Front Immunol 2021; 12:738216. [PMID: 34594340 PMCID: PMC8477019 DOI: 10.3389/fimmu.2021.738216] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 08/17/2021] [Indexed: 01/18/2023] Open
Abstract
Immunoglobulin class switch recombination (CSR) plays a crucial role in adaptive immune responses through a change of the effector functions of antibodies and is triggered by T-cell-dependent as well as T-cell-independent antigens. Signals generated following encounter with each type of antigen direct CSR to different isotypes. At the genomic level, CSR occurs between highly repetitive switch sequences located upstream of the constant gene exons of the immunoglobulin heavy chain locus. Transcription of switch sequences is mandatory for CSR and is induced in a stimulation-dependent manner. Switch transcription takes place within dynamic chromatin domains and is regulated by long-range regulatory elements which promote alignment of partner switch regions in CSR centers. Here, we review recent work and models that account for the function of long-range transcriptional regulatory elements and the chromatin-based mechanisms involved in the control of CSR.
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Affiliation(s)
- Audrey Dauba
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
| | - Ahmed Amine Khamlichi
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
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7
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Parihar SP, Ozturk M, Höft MA, Chia JE, Guler R, Keeton R, van Rensburg IC, Loxton AG, Brombacher F. IL-4-Responsive B Cells Are Detrimental During Chronic Tuberculosis Infection in Mice. Front Immunol 2021; 12:611673. [PMID: 34220793 PMCID: PMC8243286 DOI: 10.3389/fimmu.2021.611673] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 05/25/2021] [Indexed: 12/02/2022] Open
Abstract
In tuberculosis, T cell-mediated immunity is extensively studied whilst B cells received limited attention in human and mice. Of interest, Mycobacterium tuberculosis (Mtb) does increase IL-4 Receptor-alpha (IL4Rα) expression in murine B cells. To better understand the role of IL4Rα signalling in B cells, we compared wild type mice with B cell-specific IL4Rα deficient mice (mb1creIL-4Rα-/lox mice). Chronic Mtb aerosol infection in mb1creIL-4Rα-/lox mice reduced lung and spleen bacterial burdens, compared to littermate (IL-4Rα-/lox) control animals. Consequently, lung pathology, inflammation and inducible nitric oxide synthase (iNOS) expression were reduced in the lungs of mb1creIL-4Rα-/lox mice, which was also accompanied by increased lung IgA and decreased IgG1 levels. Furthermore, intratracheal adoptive transfer of wild-type B cells into B cell-specific IL4Rα deficient mice reversed the protective phenotype. Moreover, constitutively mCherry expressing Mtb showed decreased association with B cells from mb1creIL-4Rα-/lox mice ex vivo. In addition, supernatants from Mtb-exposed B cells of mb1creIL-4Rα-/lox mice also increased the ability of macrophages to produce nitric oxide, IL-1β, IL-6 and TNF. Together, this demonstrates that IL-4-responsive B cells are detrimental during the chronic phase of tuberculosis in mice with perturbed antibody profiles, inflammatory cytokines and tnf and stat1 levels in the lungs.
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Affiliation(s)
- Suraj P. Parihar
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town Component, Cape Town, South Africa
- Division of Immunology and South African Medical Research Council (SAMRC) Immunology of Infectious Diseases, Institute of Infectious Diseases and Molecular Medicine (IDM), Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Division of Medical Microbiology, Department of Pathology, Faculty of Health Sciences, Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa) and Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Mumin Ozturk
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town Component, Cape Town, South Africa
- Division of Immunology and South African Medical Research Council (SAMRC) Immunology of Infectious Diseases, Institute of Infectious Diseases and Molecular Medicine (IDM), Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Maxine A. Höft
- AFGrica Medical Mycology Research Unit, Department of Pathology, Faculty of Health Sciences, Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Julius E. Chia
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town Component, Cape Town, South Africa
- Division of Immunology and South African Medical Research Council (SAMRC) Immunology of Infectious Diseases, Institute of Infectious Diseases and Molecular Medicine (IDM), Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Reto Guler
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town Component, Cape Town, South Africa
- Division of Immunology and South African Medical Research Council (SAMRC) Immunology of Infectious Diseases, Institute of Infectious Diseases and Molecular Medicine (IDM), Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Department of Pathology, Faculty of Health Sciences, Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa) and Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Roanne Keeton
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Ilana C. van Rensburg
- DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Andre G. Loxton
- DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Frank Brombacher
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town Component, Cape Town, South Africa
- Division of Immunology and South African Medical Research Council (SAMRC) Immunology of Infectious Diseases, Institute of Infectious Diseases and Molecular Medicine (IDM), Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Department of Pathology, Faculty of Health Sciences, Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa) and Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
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8
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Abstract
Among antibodies, IgA is unique because it has evolved to be secreted onto mucosal surfaces. The structure of IgA and the associated secretory component allow IgA to survive the highly proteolytic environment of mucosal surfaces but also substantially limit IgA's ability to activate effector functions on immune cells. Despite these characteristics, IgA is critical for both preventing enteric infections and shaping the local microbiome. IgA's function is determined by a distinct antigen-binding repertoire, composed of antibodies with a variety of specificities, from permissive polyspecificity to cross-reactivity to exquisite specificity to a single epitope, which act together to regulate intestinal bacteria. Development of the unique function and specificities of IgA is shaped by local cues provided by the gut-associated lymphoid tissue, driven by the constantly changing environment of the intestine and microbiota.
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Affiliation(s)
- Timothy W Hand
- R.K. Mellon Institute for Pediatric Research, Department of Pediatrics, Division of Infectious Diseases, UPMC Children's Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, Pennsylvania 15224, USA;
| | - Andrea Reboldi
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA;
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9
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Nicolai O, Pötschke C, Schmoeckel K, Darisipudi MN, van der Linde J, Raafat D, Bröker BM. Antibody Production in Murine Polymicrobial Sepsis-Kinetics and Key Players. Front Immunol 2020; 11:828. [PMID: 32425951 PMCID: PMC7205023 DOI: 10.3389/fimmu.2020.00828] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/14/2020] [Indexed: 12/16/2022] Open
Abstract
Although antigen-specific priming of antibody responses is impaired during sepsis, there is nevertheless a strong increase in IgM and IgG serum concentrations. Using colon ascendens stent peritonitis (CASP), a mouse model of polymicrobial abdominal sepsis, we observed substantial increases in IgM as well as IgG of all subclasses, starting at day 3 and peaking 2 weeks after sepsis induction. The dominant source of antibody-secreting cells was by far the spleen, with a minor contribution of the mesenteric lymph nodes. Remarkably, sepsis induction in splenectomized mice did not change the dynamics of the serum IgM/IgG reaction, indicating that the marginal zone B cells, which almost exclusively reside in the spleen, are dispensable in such a setting. Hence, in systemic bacterial infection, the function of the spleen as dominant niche of antibody-producing cells can be compensated by extra-splenic B cell populations as well as other lymphoid organs. Depletion of CD4+ T cells did not affect the IgM response, while it impaired IgG generation of all subclasses with the exception of IgG3. Taken together, our data demonstrate that the robust class-switched antibody response in sepsis encompasses both T cell-dependent and -independent components.
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Affiliation(s)
- Oliver Nicolai
- Immunology Department, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Christian Pötschke
- Immunology Department, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Katrin Schmoeckel
- Immunology Department, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Murthy N Darisipudi
- Immunology Department, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Julia van der Linde
- Department of General Surgery, Visceral, Thoracic and Vascular Surgery, University Medicine Greifswald, Greifswald, Germany
| | - Dina Raafat
- Immunology Department, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany.,Department of Microbiology and Immunology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Barbara M Bröker
- Immunology Department, Institute of Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald, Germany
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10
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Santos JM, Oudinet C, Schöne L, Dauba A, Khamlichi AA. Essential role of the initial activation signal in isotype selection upon deletion of a transcriptionally committed promoter. Sci Rep 2019; 9:18543. [PMID: 31811188 PMCID: PMC6898632 DOI: 10.1038/s41598-019-54929-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 11/21/2019] [Indexed: 01/31/2023] Open
Abstract
Class switch recombination (CSR), which targets exclusively the constant region of the immunoglobulin heavy chain (IgH) locus, plays an important role in humoral immunity by generating different antibody effector functions. The IgH constant locus contains multiple genes controlled by isotype (I) promoters induced by extracellular signals that activate specific I promoters, leading to B cell commitment. However, it is unknown whether after initial commitment to one promoter, non-responsive I promoters are irreversibly silent or if they can be activated after exposure to their specific inducers. Here, we studied the murine cell line CH12, which is committed to produce IgA in response to TGF-β. We show that, although other promoters than Iα are transcriptionally inactive, they are not irreversibly silent. Following deletion of the committed Iα promoter by CRISPR/Cas9, other I promoters display a complex transcriptional pattern largely dependent on the initial committing signal.
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Affiliation(s)
- Joana M Santos
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France
| | - Chloé Oudinet
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France
| | - Lisa Schöne
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France
| | - Audrey Dauba
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France
| | - Ahmed Amine Khamlichi
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, 31077, Toulouse, France.
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11
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The Nod2 Agonist Muramyl Dipeptide Cooperates with the TLR4 Agonist Lipopolysaccharide to Enhance IgG2b Production in Mouse B Cells. J Immunol Res 2019; 2019:2724078. [PMID: 31886297 PMCID: PMC6899285 DOI: 10.1155/2019/2724078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 09/25/2019] [Accepted: 10/19/2019] [Indexed: 11/28/2022] Open
Abstract
Many studies have shown that Toll-like receptors (TLRs) and Nod-like receptors (NLRs) were expressed in B cells and their signaling affects B cell functions. Nonetheless, the roles played by these receptors in B cell antibody (Ab) production have not been completely elucidated. In the present study, we examined the effect of the Nod2 agonist muramyl dipeptide (MDP) in combination with the TLR4 agonist lipopolysaccharide (LPS), a well-known B cell mitogen, on B cell viability, proliferation, and activation, and Ab production by in vitro culture of purified mouse spleen resting B cells. MDP combined with LPS to reinforce B cell viability, proliferation, and activation. Moreover, MDP enhanced LPS-induced IgG2b production, germline γ2b transcript (GLTγ2b) expression, and surface IgG2b expression. In an experiment with Nod2- and TLR4-deficient mouse B cells, we observed that the combined effect of MDP and LPS is dependent on Nod2 and TLR4 receptors. Furthermore, the combined effect on B cell viability and IgG2b switching was not observed in Rip2-deficient mouse cells. Collectively, this study suggests that Nod2 signaling enhances TLR4-activated B cell proliferation, IgG2b switching, and IgG2b production.
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12
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Zhang Y, Zhang X, Ba Z, Liang Z, Dring EW, Hu H, Lou J, Kyritsis N, Zurita J, Shamim MS, Presser Aiden A, Lieberman Aiden E, Alt FW. The fundamental role of chromatin loop extrusion in physiological V(D)J recombination. Nature 2019; 573:600-604. [PMID: 31511698 PMCID: PMC6867615 DOI: 10.1038/s41586-019-1547-y] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 08/12/2019] [Indexed: 11/24/2022]
Abstract
RAG endonuclease initiates IgH locus (Igh) V(D)J assembly in progenitor (pro)-B cells by joining Ds to JHs, before joining upstream VHs to DJH intermediates1. In mouse pro-B cells, the CTCF-binding element (CBE)-anchored chromatin loop domain2 at the 3’end of Igh contains an internal sub-domain spanning the 5’CBE anchor (IGCR1)3, the DHs, and a RAG-bound recombination center (RC)4. The RC comprises JH-proximal D (DQ52), 4 JHs, and the intronic enhancer (“iEμ”)5. Robust RAG cleavage is restricted to paired V(D)J segments flanked by complementary recombination signal sequences (12RSSs and 23RSSs)6. Ds are flanked downstream and upstream by 12RSSs that, respectively, mediate deletional joining with convergently-oriented JH-23RSSs and VH-23RSSs6. Despite 12/23 compatibility, inversional D to JH joining via upstream D-12RSSs is rare7,8. Plasmid-based assays attributed lack of inversional D to JH joining to sequence-based preference for downstream D-12RSSs9, as opposed to putative linear scanning mechanisms10,11. Given recent findings that RAG linearly scans convergent CBE-anchored chromatin loops4,12-14, potentially formed by cohesin-mediated loop extrusion15-18, we revisited a scanning role. Here, we report that JH-23RSS chromosomal orientation programs RC-bound RAG to linearly scan upstream chromatin in the 3’Igh sub-domain for convergently-oriented D-12RSSs and, thereby, to mediate deletional joining of all Ds, except RC-based DQ52 that joins by a diffusion-related mechanism. In a DQ52-based RC, formed in the absence of JHs, RAG bound by the downstream DQ52-RSS scans the downstream constant region exon-containing 3’Igh sub-domain in which scanning can be impeded by targeted nuclease-dead Cas9 (dCas9) binding, by transcription through repetitive Igh switch sequences, and by the 3’Igh CBE-based loop anchor. Notably, each scanning impediment focally increases RAG activity on potential substrate sequences within the impeded region. High resolution mapping of RC chromatin interactions reveals that such focal RAG targeting is associated with corresponding impediments to the loop extrusion process that drives chromatin past RC-bound RAG.
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Affiliation(s)
- Yu Zhang
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Boston, MA, USA.,Center for Immunobiology, Department of Biomedical Sciences, Western Michigan University Homer Stryker M.D. School of Medicine, Kalamazoo, MI, USA.,Center for Immunobiology, Department of Biomedical Sciences, Western Michigan University Homer Stryker M.D. School of Medicine, Kalamazoo, MI, USA
| | - Xuefei Zhang
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Boston, MA, USA
| | - Zhaoqing Ba
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Boston, MA, USA
| | - Zhuoyi Liang
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Boston, MA, USA
| | - Edward W Dring
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Boston, MA, USA
| | - Hongli Hu
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Boston, MA, USA
| | - Jiangman Lou
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Boston, MA, USA
| | - Nia Kyritsis
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Boston, MA, USA
| | - Jeffrey Zurita
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA.,Howard Hughes Medical Institute, Boston, MA, USA
| | - Muhammad S Shamim
- The Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Bioengineering, Rice University, Houston, TX, USA.,Department of Computer Science, Rice University, Houston, TX, USA.,Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
| | - Aviva Presser Aiden
- The Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Bioengineering, Rice University, Houston, TX, USA.,Department of Pediatrics, Texas Children's Hospital, Houston, TX, USA
| | - Erez Lieberman Aiden
- The Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Computer Science, Rice University, Houston, TX, USA.,Center for Theoretical Biological Physics, Rice University, Houston, TX, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, USA.,Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
| | - Frederick W Alt
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA. .,Department of Genetics, Harvard Medical School, Boston, MA, USA. .,Howard Hughes Medical Institute, Boston, MA, USA.
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13
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Le Coz C, Bengsch B, Khanna C, Trofa M, Ohtani T, Nolan BE, Henrickson SE, Lambert MP, Kim TO, Despotovic JM, Feldman S, Fadugba OO, Takach P, Ruffner M, Jyonouchi S, Heimall J, Sullivan KE, Wherry EJ, Romberg N. Common variable immunodeficiency-associated endotoxemia promotes early commitment to the T follicular lineage. J Allergy Clin Immunol 2019; 144:1660-1673. [PMID: 31445098 DOI: 10.1016/j.jaci.2019.08.007] [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] [Received: 04/12/2019] [Revised: 07/26/2019] [Accepted: 08/05/2019] [Indexed: 12/27/2022]
Abstract
BACKGROUND Although chiefly a B-lymphocyte disorder, several research groups have identified common variable immunodeficiency (CVID) subjects with numeric and/or functional TH cell alterations. The causes, interrelationships, and consequences of CVID-associated CD4+ T-cell derangements to hypogammaglobulinemia, autoantibody production, or both remain unclear. OBJECTIVE We sought to determine how circulating CD4+ T cells are altered in CVID subjects with autoimmune cytopenias (AICs; CVID+AIC) and the causes of these derangements. METHODS Using hypothesis-generating, high-dimensional single-cell analyses, we created comprehensive phenotypic maps of circulating CD4+ T cells. Differences between subject groups were confirmed in a large and genetically diverse cohort of CVID subjects (n = 69) by using flow cytometry, transcriptional profiling, multiplex cytokine/chemokine detection, and a suite of in vitro functional assays measuring naive T-cell differentiation, B-cell/T-cell cocultures, and regulatory T-cell suppression. RESULTS Although CD4+ TH cell profiles from healthy donors and CVID subjects without AICs were virtually indistinguishable, T cells from CVID+AIC subjects exhibited follicular features as early as thymic egress. Follicular skewing correlated with IgA deficiency-associated endotoxemia and endotoxin-induced expression of activin A and inducible T-cell costimulator ligand. The resulting enlarged circulating follicular helper T-cell population from CVID+AIC subjects provided efficient help to receptive healthy donor B cells but not unresponsive CVID B cells. Despite this, circulating follicular helper T cells from CVID+AIC subjects exhibited aberrant transcriptional profiles and altered chemokine/cytokine receptor expression patterns that interfered with regulatory T-cell suppression assays and were associated with autoantibody production. CONCLUSIONS Endotoxemia is associated with early commitment to the follicular T-cell lineage in IgA-deficient CVID subjects, particularly those with AICs.
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Affiliation(s)
- Carole Le Coz
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Bertram Bengsch
- Department of Medicine II, University Medical Center Freiburg, Freiburg, Germany
| | - Caroline Khanna
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Melissa Trofa
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Takuya Ohtani
- Institute for Immunology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa
| | - Brian E Nolan
- Division of Rheumatology, Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Sarah E Henrickson
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, Pa; Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa; Institute for Immunology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa
| | - Michele P Lambert
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pa; Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa
| | - Taylor Olmsted Kim
- Department of Pediatrics, Hematology/Oncology Section, Baylor College of Medicine, Houston, Tex
| | - Jenny M Despotovic
- Department of Pediatrics, Hematology/Oncology Section, Baylor College of Medicine, Houston, Tex
| | - Scott Feldman
- Department of Medicine, Division of Allergy and Immunology,Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa
| | - Olajumoke O Fadugba
- Department of Medicine, Division of Allergy and Immunology,Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa
| | - Patricia Takach
- Department of Medicine, Division of Allergy and Immunology,Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa
| | - Melanie Ruffner
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Soma Jyonouchi
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, Pa; Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa
| | - Jennifer Heimall
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, Pa; Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa
| | - Kathleen E Sullivan
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, Pa; Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa; Institute for Immunology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa
| | - E John Wherry
- Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa; Institute for Immunology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa
| | - Neil Romberg
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, Pa; Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa; Institute for Immunology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pa.
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14
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Yeap LS, Meng FL. Cis- and trans-factors affecting AID targeting and mutagenic outcomes in antibody diversification. Adv Immunol 2019; 141:51-103. [PMID: 30904133 DOI: 10.1016/bs.ai.2019.01.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Antigen receptor diversification is a hallmark of adaptive immunity which allows specificity of the receptor to particular antigen. B cell receptor (BCR) or its secreted form, antibody, is diversified through antigen-independent and antigen-dependent mechanisms. During B cell development in bone marrow, BCR is diversified via V(D)J recombination mediated by RAG endonuclease. Upon stimulation by antigen, B cell undergo somatic hypermutation (SHM) to allow affinity maturation and class switch recombination (CSR) to change the effector function of the antibody. Both SHM and CSR are initiated by activation-induced cytidine deaminase (AID). Repair of AID-initiated lesions through different DNA repair pathways results in diverse mutagenic outcomes. Here, we focus on discussing cis- and trans-factors that target AID to its substrates and factors that affect different outcomes of AID-initiated lesions. The knowledge of mechanisms that govern AID targeting and outcomes could be harnessed to elicit rare functional antibodies and develop ex vivo antibody diversification approaches with diversifying base editors.
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Affiliation(s)
- Leng-Siew Yeap
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Fei-Long Meng
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.
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15
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Delgado-Benito V, Rosen DB, Wang Q, Gazumyan A, Pai JA, Oliveira TY, Sundaravinayagam D, Zhang W, Andreani M, Keller L, Kieffer-Kwon KR, Pękowska A, Jung S, Driesner M, Subbotin RI, Casellas R, Chait BT, Nussenzweig MC, Di Virgilio M. The Chromatin Reader ZMYND8 Regulates Igh Enhancers to Promote Immunoglobulin Class Switch Recombination. Mol Cell 2018; 72:636-649.e8. [PMID: 30293785 PMCID: PMC6242708 DOI: 10.1016/j.molcel.2018.08.042] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 07/01/2018] [Accepted: 08/25/2018] [Indexed: 01/18/2023]
Abstract
Class switch recombination (CSR) is a DNA recombination reaction that diversifies the effector component of antibody responses. CSR is initiated by activation-induced cytidine deaminase (AID), which targets transcriptionally active immunoglobulin heavy chain (Igh) switch donor and acceptor DNA. The 3′ Igh super-enhancer, 3′ regulatory region (3′RR), is essential for acceptor region transcription, but how this function is regulated is unknown. Here, we identify the chromatin reader ZMYND8 as an essential regulator of the 3′RR. In B cells, ZMYND8 binds promoters and super-enhancers, including the Igh enhancers. ZMYND8 controls the 3′RR activity by modulating the enhancer transcriptional status. In its absence, there is increased 3′RR polymerase loading and decreased acceptor region transcription and CSR. In addition to CSR, ZMYND8 deficiency impairs somatic hypermutation (SHM) of Igh, which is also dependent on the 3′RR. Thus, ZMYND8 controls Igh diversification in mature B lymphocytes by regulating the activity of the 3′ Igh super-enhancer. ZMYND8 is required for GLT of acceptor S regions and Class Switch Recombination ZMYND8 supports efficient somatic hypermutation of the Igh variable regions ZMYND8 binds B cell super-enhancers, including the 3′ Igh enhancer ZMYND8 modulates the transcriptional status and activity of the 3′ Igh enhancer
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Affiliation(s)
- Verónica Delgado-Benito
- Laboratory of DNA Repair and Maintenance of Genome Stability, The Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Daniel B Rosen
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Qiao Wang
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Anna Gazumyan
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Joy A Pai
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Thiago Y Oliveira
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Devakumar Sundaravinayagam
- Laboratory of DNA Repair and Maintenance of Genome Stability, The Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Wenzhu Zhang
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Matteo Andreani
- Laboratory of DNA Repair and Maintenance of Genome Stability, The Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Lisa Keller
- Laboratory of DNA Repair and Maintenance of Genome Stability, The Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | | | | | - Seolkyoung Jung
- Lymphocyte Nuclear Biology, NIAMS, NCI, NIH, Bethesda, MD 20892, USA
| | - Madlen Driesner
- Laboratory of DNA Repair and Maintenance of Genome Stability, The Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Roman I Subbotin
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Rafael Casellas
- Lymphocyte Nuclear Biology, NIAMS, NCI, NIH, Bethesda, MD 20892, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065, USA
| | - Michel C Nussenzweig
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Michela Di Virgilio
- Laboratory of DNA Repair and Maintenance of Genome Stability, The Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany.
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16
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Yewdell WT, Chaudhuri J. A transcriptional serenAID: the role of noncoding RNAs in class switch recombination. Int Immunol 2018; 29:183-196. [PMID: 28535205 DOI: 10.1093/intimm/dxx027] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 05/22/2017] [Indexed: 12/31/2022] Open
Abstract
During an immune response, activated B cells may undergo class switch recombination (CSR), a molecular rearrangement that allows B cells to switch from expressing IgM and IgD to a secondary antibody heavy chain isotype such as IgG, IgA or IgE. Secondary antibody isotypes provide the adaptive immune system with distinct effector functions to optimally combat various pathogens. CSR occurs between repetitive DNA elements within the immunoglobulin heavy chain (Igh) locus, termed switch (S) regions and requires the DNA-modifying enzyme activation-induced cytidine deaminase (AID). AID-mediated DNA deamination within S regions initiates the formation of DNA double-strand breaks, which serve as biochemical beacons for downstream DNA repair pathways that coordinate the ligation of DNA breaks. Myriad factors contribute to optimal AID targeting; however, many of these factors also localize to genomic regions outside of the Igh locus. Thus, a current challenge is to explain the specific targeting of AID to the Igh locus. Recent studies have implicated noncoding RNAs in CSR, suggesting a provocative mechanism that incorporates Igh-specific factors to enable precise AID targeting. Here, we chronologically recount the rich history of noncoding RNAs functioning in CSR to provide a comprehensive context for recent and future discoveries. We present a model for the RNA-guided targeting of AID that attempts to integrate historical and recent findings, and highlight potential caveats. Lastly, we discuss testable hypotheses ripe for current experimentation, and explore promising ideas for future investigations.
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Affiliation(s)
- William T Yewdell
- Immunology Program, Memorial Sloan Kettering Cancer, New York, NY 10065, USA
| | - Jayanta Chaudhuri
- Immunology Program, Memorial Sloan Kettering Cancer, New York, NY 10065, USA.,Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
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17
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Liu X, Meng FL. Generation of Genomic Alteration from Cytidine Deamination. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1044:49-64. [DOI: 10.1007/978-981-13-0593-1_5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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18
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Kitaura K, Yamashita H, Ayabe H, Shini T, Matsutani T, Suzuki R. Different Somatic Hypermutation Levels among Antibody Subclasses Disclosed by a New Next-Generation Sequencing-Based Antibody Repertoire Analysis. Front Immunol 2017; 8:389. [PMID: 28515723 PMCID: PMC5413556 DOI: 10.3389/fimmu.2017.00389] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 03/20/2017] [Indexed: 12/24/2022] Open
Abstract
A diverse antibody repertoire is primarily generated by the rearrangement of V, D, and J genes and subsequent somatic hypermutation (SHM). Class-switch recombination (CSR) produces various isotypes and subclasses with different functional properties. Although antibody isotypes and subclasses are considered to be produced by both direct and sequential CSR, it is still not fully understood how SHMs accumulate during the process in which antibody subclasses are generated. Here, we developed a new next-generation sequencing (NGS)-based antibody repertoire analysis capable of identifying all antibody isotype and subclass genes and used it to examine the peripheral blood mononuclear cells of 12 healthy individuals. Using a total of 5,480,040 sequences, we compared percentage frequency of variable (V), junctional (J) sequence, and a combination of V and J, diversity, length, and amino acid compositions of CDR3, SHM, and shared clones in the IgM, IgD, IgG3, IgG1, IgG2, IgG4, IgA1, IgE, and IgA2 genes. The usage and diversity were similar among the immunoglobulin (Ig) subclasses. Clonally related sequences sharing identical V, D, J, and CDR3 amino acid sequences were frequently found within multiple Ig subclasses, especially between IgG1 and IgG2 or IgA1 and IgA2. SHM occurred most frequently in IgG4, while IgG3 genes were the least mutated among all IgG subclasses. The shared clones had almost the same SHM levels among Ig subclasses, while subclass-specific clones had different levels of SHM dependent on the genomic location. Given the sequential CSR, these results suggest that CSR occurs sequentially over multiple subclasses in the order corresponding to the genomic location of IGHCs, but CSR is likely to occur more quickly than SHMs accumulate within Ig genes under physiological conditions. NGS-based antibody repertoire analysis should provide critical information on how various antibodies are generated in the immune system.
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Affiliation(s)
| | | | - Hitomi Ayabe
- Repertoire Genesis Incorporation, Ibaraki, Japan
| | - Tadasu Shini
- BITS Co. Ltd., Tokyo, Japan.,Department of Rheumatology and Clinical Immunology, Clinical Research Center for Rheumatology and Allergy, Sagamihara National Hospital, National Hospital Organization, Sagamihara, Japan
| | | | - Ryuji Suzuki
- Repertoire Genesis Incorporation, Ibaraki, Japan.,Department of Rheumatology and Clinical Immunology, Clinical Research Center for Rheumatology and Allergy, Sagamihara National Hospital, National Hospital Organization, Sagamihara, Japan
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19
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Seo BS, Yoon HK, Shin J, Park HY, Lee SH, Lee JE, Yoo YC, Lee J, Kim PH, Park SR. Cloning and analysis of promoter region of mouse immunoglobulin germline γ3 transcripts. Genes Genomics 2016. [DOI: 10.1007/s13258-016-0450-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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20
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Seo BS, Park HY, Yoon HK, Yoo YC, Lee J, Park SR. Dectin-1 agonist selectively induces IgG1 class switching by LPS-activated mouse B cells. Immunol Lett 2016; 178:114-21. [DOI: 10.1016/j.imlet.2016.08.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 08/03/2016] [Accepted: 08/24/2016] [Indexed: 11/28/2022]
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21
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Batool M, Anwar MA, Choi S. Toll-like receptors targeting technology for the treatment of lymphoma. Expert Opin Drug Discov 2016; 11:1047-1059. [PMID: 27602749 DOI: 10.1080/17460441.2016.1233964] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION The crucial role of Toll-like Receptors (TLRs) in innate and adaptive immune systems is well discussed in the literature. In cancer, TLRs act as a double-edged sword that can promote or suppress tumor growth. Areas covered: In this article, the authors uncover the potential role of TLRs in lymphomas, which are cancers related to the lymphatic system and blood cells. TLRs are de facto inflammation-inducing receptors that can either worsen disease or ameliorate lymphoma treatment. From this perspective, the usage of TLRs to modulate the immune system toward lymphoma regression is desirable. Various strategies have been used so far, and novel ways are being sought out to cure lymphoma. Expert opinion: TLR ligands have successfully been used to improve patient health; however, these receptors must be finely tuned to further optimize therapy. For a better outcome, novel specific ligands, improved pharmacodynamics, and unique targets should be discerned. Ligands with conjugated molecules, nanoparticles, and targeted drug delivery can highly optimize the therapy for lymphoma with various etiologies.
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Affiliation(s)
- Maria Batool
- a Department of Molecular Science and Technology , Ajou University , Suwon , Korea
| | - Muhammad Ayaz Anwar
- a Department of Molecular Science and Technology , Ajou University , Suwon , Korea
| | - Sangdun Choi
- a Department of Molecular Science and Technology , Ajou University , Suwon , Korea
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22
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Related Mechanisms of Antibody Somatic Hypermutation and Class Switch Recombination. Microbiol Spectr 2016; 3:MDNA3-0037-2014. [PMID: 26104555 DOI: 10.1128/microbiolspec.mdna3-0037-2014] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The primary antibody repertoire is generated by mechanisms involving the assembly of the exons that encode the antigen-binding variable regions of immunoglobulin heavy (IgH) and light (IgL) chains during the early development of B lymphocytes. After antigen-dependent activation, mature B lymphocytes can further alter their IgH and IgL variable region exons by the process of somatic hypermutation (SHM), which allows the selection of B cells in which SHMs resulted in the production of antibodies with increased antigen affinity. In addition, during antigen-dependent activation, B cells can also change the constant region of their IgH chain through a DNA double-strand-break (DSB) dependent process referred to as IgH class switch recombination (CSR), which generates B cell progeny that produce antibodies with different IgH constant region effector functions that are best suited for a elimination of a particular pathogen or in a particular setting. Both the mutations that underlie SHM and the DSBs that underlie CSR are initiated in target genes by activation-induced cytidine deaminase (AID). This review describes in depth the processes of SHM and CSR with a focus on mechanisms that direct AID cytidine deamination in activated B cells and mechanisms that promote the differential outcomes of such cytidine deamination.
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23
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Sharifi L, Mirshafiey A, Rezaei N, Azizi G, Magaji Hamid K, Amirzargar AA, Asgardoon MH, Aghamohammadi A. The role of toll-like receptors in B-cell development and immunopathogenesis of common variable immunodeficiency. Expert Rev Clin Immunol 2015; 12:195-207. [PMID: 26654573 DOI: 10.1586/1744666x.2016.1114885] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Common variable immunodeficiency (CVID) is the most frequent symptomatic primary immune deficiency and is characterized by hypogammaglobulinemia, defect in specific antibody response and increased susceptibility to recurrent infections, malignancy and autoimmunity. Patients with CVID often have defects in post-antigenic B-cell differentiation, with fewer memory B cells and impaired isotype switching. Toll-like receptors (TLRs) are expressed on various immune cells as key elements of innate and adaptive immunity. TLR signaling in B cells plays multiple roles in cell differentiation and activation, class-switch recombination and cytokine and antibody production. Moreover, recent studies have shown functional alteration of TLRs responses in CVID patients including poor cell proliferation, impaired upregulation of co-stimulatory molecules and failure in cytokine and immunoglobulin production. The purpose of the present review is to discuss the role of TLRs in B-cell development and function as well as their role in the immunopathogenesis of CVID.
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Affiliation(s)
- Laleh Sharifi
- a Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center , Tehran University of Medical Sciences , Tehran , Iran
| | - Abbas Mirshafiey
- a Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center , Tehran University of Medical Sciences , Tehran , Iran.,b Department of Immunology, School of Public Health , Tehran University of Medical Sciences , Tehran , Iran
| | - Nima Rezaei
- a Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center , Tehran University of Medical Sciences , Tehran , Iran.,c Department of Immunology, School of Medicine , Tehran University of Medical Sciences , Tehran , Iran
| | - Gholamreza Azizi
- d Imam Hassan Mojtaba Hospital , Alborz University of Medical Sciences , Karaj , Iran
| | - Kabir Magaji Hamid
- b Department of Immunology, School of Public Health , Tehran University of Medical Sciences , Tehran , Iran.,e Immunology Department, Faculty of Medical Laboratory Sciences , Usmanu Danfodiyo University , Sokoto , Nigeria
| | - Ali Akbar Amirzargar
- c Department of Immunology, School of Medicine , Tehran University of Medical Sciences , Tehran , Iran
| | - Mohammad Hossein Asgardoon
- a Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center , Tehran University of Medical Sciences , Tehran , Iran
| | - Asghar Aghamohammadi
- a Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center , Tehran University of Medical Sciences , Tehran , Iran
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Chandra V, Bortnick A, Murre C. AID targeting: old mysteries and new challenges. Trends Immunol 2015; 36:527-35. [PMID: 26254147 DOI: 10.1016/j.it.2015.07.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 07/14/2015] [Accepted: 07/14/2015] [Indexed: 01/09/2023]
Abstract
Activation-induced cytidine deaminase (AID) mediates cytosine deamination and underlies two central processes in antibody diversification: somatic hypermutation and class-switch recombination. AID deamination is not exclusive to immunoglobulin loci; it can instigate DNA lesions in non-immunoglobulin genes and thus stringent checks are in place to constrain and restrict its activity. Recent findings have provided new insights into the mechanisms that target AID activity to specific genomic regions, revealing an involvement for noncoding RNAs associated with polymerase pausing and with enhancer transcription as well as genomic architecture. We review these findings and integrate them into a model for multilevel regulation of AID expression and targeting in immunoglobulin and non-immunoglobulin loci. Within this framework we discuss gaps in understanding, and outline important areas of further research.
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Affiliation(s)
- Vivek Chandra
- Department of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093-0377, USA
| | - Alexandra Bortnick
- Department of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093-0377, USA
| | - Cornelis Murre
- Department of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093-0377, USA.
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25
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Severinson E. Identification of the IgG1 Induction Factor (Interleukin 4). Front Immunol 2014; 5:628. [PMID: 25538711 PMCID: PMC4260516 DOI: 10.3389/fimmu.2014.00628] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 11/24/2014] [Indexed: 11/13/2022] Open
Affiliation(s)
- Eva Severinson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University , Stockholm , Sweden
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26
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Isaza-Correa JM, Liang Z, van den Berg A, Diepstra A, Visser L. Toll-like receptors in the pathogenesis of human B cell malignancies. J Hematol Oncol 2014; 7:57. [PMID: 25112836 PMCID: PMC4237867 DOI: 10.1186/s13045-014-0057-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 07/28/2014] [Indexed: 12/20/2022] Open
Abstract
Toll-like receptors (TLRs) are important players in B-cell activation, maturation and memory and may be involved in the pathogenesis of B-cell lymphomas. Accumulating studies show differential expression in this heterogeneous group of cancers. Stimulation with TLR specific ligands, or agonists of their ligands, leads to aberrant responses in the malignant B-cells. According to current data, TLRs can be implicated in malignant transformation, tumor progression and immune evasion processes. Most of the studies focused on multiple myeloma and chronic lymphocytic leukemia, but in the last decade the putative role of TLRs in other types of B-cell lymphomas has gained much interest. The aim of this review is to discuss recent findings on the role of TLRs in normal B cell functioning and their role in the pathogenesis of B-cell malignancies.
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Matthews AJ, Zheng S, DiMenna LJ, Chaudhuri J. Regulation of immunoglobulin class-switch recombination: choreography of noncoding transcription, targeted DNA deamination, and long-range DNA repair. Adv Immunol 2014; 122:1-57. [PMID: 24507154 PMCID: PMC4150736 DOI: 10.1016/b978-0-12-800267-4.00001-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Upon encountering antigens, mature IgM-positive B lymphocytes undergo class-switch recombination (CSR) wherein exons encoding the default Cμ constant coding gene segment of the immunoglobulin (Ig) heavy-chain (Igh) locus are excised and replaced with a new constant gene segment (referred to as "Ch genes", e.g., Cγ, Cɛ, or Cα). The B cell thereby changes from expressing IgM to one producing IgG, IgE, or IgA, with each antibody isotype having a different effector function during an immune reaction. CSR is a DNA deletional-recombination reaction that proceeds through the generation of DNA double-strand breaks (DSBs) in repetitive switch (S) sequences preceding each Ch gene and is completed by end-joining between donor Sμ and acceptor S regions. CSR is a multistep reaction requiring transcription through S regions, the DNA cytidine deaminase AID, and the participation of several general DNA repair pathways including base excision repair, mismatch repair, and classical nonhomologous end-joining. In this review, we discuss our current understanding of how transcription through S regions generates substrates for AID-mediated deamination and how AID participates not only in the initiation of CSR but also in the conversion of deaminated residues into DSBs. Additionally, we review the multiple processes that regulate AID expression and facilitate its recruitment specifically to the Ig loci, and how deregulation of AID specificity leads to oncogenic translocations. Finally, we summarize recent data on the potential role of AID in the maintenance of the pluripotent stem cell state during epigenetic reprogramming.
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Affiliation(s)
- Allysia J Matthews
- Immunology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, USA; Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, New York, USA
| | - Simin Zheng
- Immunology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, USA; Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, New York, USA
| | - Lauren J DiMenna
- Immunology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, USA; Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, New York, USA
| | - Jayanta Chaudhuri
- Immunology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, USA; Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, New York, USA.
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28
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Cho SH, Raybuck A, Wei M, Erickson J, Nam KT, Cox RG, Trochtenberg A, Thomas JW, Williams J, Boothby M. B cell-intrinsic and -extrinsic regulation of antibody responses by PARP14, an intracellular (ADP-ribosyl)transferase. THE JOURNAL OF IMMUNOLOGY 2013; 191:3169-78. [PMID: 23956424 DOI: 10.4049/jimmunol.1301106] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The capacity to achieve sufficient concentrations of Ag-specific Ab of the appropriate isotypes is a critical component of immunity that requires efficient differentiation and interactions of Ag-specific B and Th cells along with dendritic cells. Numerous bacterial toxins catalyze mono(ADP-ribosyl)ation of mammalian proteins to influence cell physiology and adaptive immunity. However, little is known about biological functions of intracellular mammalian mono(ADP-ribosyl)transferases, such as any ability to regulate Ab responses. poly-(ADP-ribose) polymerase 14 (PARP14), an intracellular protein highly expressed in lymphoid cells, binds to STAT6 and encodes a catalytic domain with mammalian mono(ADP-ribosyl)transferase activity. In this article, we show that recall IgA as well as the STAT6-dependent IgE Ab responses are impaired in PARP14-deficient mice. Whereas PARP14 regulation of IgE involved a B cell-intrinsic process, the predominant impact on IgA was B cell extrinsic. Of note, PARP14 deficiency reduced the levels of Th17 cells and CD103⁺ DCs, which are implicated in IgA regulation. PARP14 enhanced the expression of RORα, Runx1, and Smad3 after T cell activation, and, importantly, its catalytic activity of PARP14 promoted Th17 differentiation. Collectively, the findings show that PARP14 influences the class distribution, affinity repertoire, and recall capacity of Ab responses in mice, as well as provide direct evidence of the requirement for protein mono-ADP-ribosylation in Th cell differentiation.
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Affiliation(s)
- Sung Hoon Cho
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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29
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Jaszczur M, Bertram JG, Pham P, Scharff MD, Goodman MF. AID and Apobec3G haphazard deamination and mutational diversity. Cell Mol Life Sci 2012. [PMID: 23178850 DOI: 10.1007/s00018-012-1212-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Activation-induced deoxycytidine deaminase (AID) and Apobec 3G (Apo3G) cause mutational diversity by initiating mutations on regions of single-stranded (ss) DNA. Expressed in B cells, AID deaminates C → U in actively transcribed immunoglobulin (Ig) variable and switch regions to initiate the somatic hypermutation (SHM) and class switch recombination (CSR) that are essential for antibody diversity. Apo3G expressed in T cells catalyzes C deaminations on reverse transcribed cDNA causing HIV-1 retroviral inactivation. When operating properly, AID- and Apo3G-initiated mutations boost human fitness. Yet, both enzymes are potentially powerful somatic cell "mutators". Loss of regulated expression and proper genome targeting can cause human cancer. Here, we review well-established biological roles of AID and Apo3G. We provide a synopsis of AID partnering proteins during SHM and CSR, and describe how an Apo2 crystal structure provides "surrogate" insight for AID and Apo3G biochemical behavior. However, large gaps remain in our understanding of how dC deaminases search ssDNA to identify trinucleotide motifs to deaminate. We discuss two recent methods to analyze ssDNA scanning and deamination. Apo3G scanning and deamination is visualized in real-time using single-molecule FRET, and AID deamination efficiencies are determined with a random walk analysis. AID and Apo3G encounter many candidate deamination sites while scanning ssDNA. Generating mutational diversity is a principal aim of AID and an important ancillary property of Apo3G. Success seems likely to involve hit and miss deamination motif targeting, biased strongly toward miss.
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Affiliation(s)
- Malgorzata Jaszczur
- Departments of Biological Sciences and Chemistry, Molecular and Computational Biology Section, University of Southern California, Los Angeles, CA 90089-2910, USA
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Sealy R, Webby RJ, Crumpton JC, Hurwitz JL. Differential localization and function of antibody-forming cells responsive to inactivated or live-attenuated influenza virus vaccines. Int Immunol 2012; 25:183-95. [PMID: 23143476 DOI: 10.1093/intimm/dxs107] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Currently, there are two different types of licensed influenza virus vaccines available in the USA, the live attenuated cold-adapted vaccine and the inactivated vaccine. Children greater than 2 years of age and adults younger than 50 years (apart from those suffering from immunodeficiencies or lung disease) may choose between the two vaccines. Previous studies have shown that both vaccines elicit significant serum antibody responses. However, comprehensive analyses of antibody-forming cells (AFCs) in the upper respiratory tract (URT), the critical site of pathogen entry, have been lacking. We therefore compared influenza virus-specific antibody and AFC activities in systemic and mucosal tissues following immunizations of cotton rats with inactivated or live-attenuated vaccines, including vaccines from the 2009-10 and 2010-11 seasons. Results demonstrated that inactivated and live-attenuated vaccines induced virus-specific AFCs, but patterns of residence and function were highly disparate. The inactivated vaccine elicited AFCs predominantly in the spleen and bone marrow; IgG was the main isotype. In contrast, the live attenuated vaccine elicited acute and long-sustained AFC responses in the diffuse nasal-associated lymphoid tissue (d-NALT) and lung, with IgA being the predominant isotype. The appearance of these d-NALT URT responses was confirmed by a similar study of the 2009-10 live attenuated vaccine in ferrets. Data emphasize that the inactivated and live-attenuated vaccines that are each capable of protecting humans from influenza virus disease do so by very different modes of immune surveillance.
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Affiliation(s)
- Robert Sealy
- Department of Infectious Diseases, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, USA
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Abstract
The discovery of host-encoded gene products that sense molecular patterns in infectious microbes, and the demonstration of their role in triggering innate and adaptive immune responses, has been a key milestone in our understanding of immunology. Twenty-three years after Janeway first outlined the fundamental concepts of the 'pattern recognition' model, and 15 years since the identification of Toll-like receptors (TLRs) as pattern recognition receptors (PRRs), new insights continue to be revealed, and questions remain. For example, innate immune responses to microbes that are mediated by PRRs have historically been viewed as the domain of innate immune cell populations such as dendritic cells and macrophages. New evidence, however, has pointed to the role of B-cell-intrinsic TLR activation in shaping antibody responses. These studies have revealed that TLRs regulate a complex transcriptional network that controls multiple steps in the development of antigen-specific antibodies. This review covers these recent developments regarding the role of TLRs in B-cell gene expression and function in vitro and in vivo, and highlights the remaining challenges in the field, with particular emphasis on the role of TLRs in antibody responses to viral infection. A more complete understanding of how TLRs regulate antibody responses will lead to improved vaccine design.
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Affiliation(s)
- Edward P Browne
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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32
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Abstract
Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract viral disease in infants and young children. Presently, there are no explicit recommendations for RSV treatment apart from supportive care. The virus is therefore responsible for an estimated 160,000 deaths per year worldwide. Despite half a century of dedicated research, there remains no licensed vaccine product. Herein are described past and current efforts to harness innate and adaptive immune potentials to combat RSV. A plethora of candidate vaccine products and strategies are reviewed. The development of a successful RSV vaccine may ultimately stem from attention to historical lessons, in concert with an integral partnering of immunology and virology research fields.
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Affiliation(s)
- Julia L Hurwitz
- Department of Infectious Diseases, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.
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Abstract
Antibody maturation requires class switch recombination (CSR) and somatic hypermutation (SHM), both of which are initiated by activation-induced cytidine deaminase (AID). AID deaminates cytosine residues resulting in mismatches that are differentially processed to produce double-strand breaks in Ig switch (S) regions that lead to CSR, or to point mutations in variable (V) exons resulting in SHM. Although AID was first thought to be Ig-specific, recent work indicates that it also targets a diverse group of non-Ig loci, including genes such as Bcl6 and c-myc, whose modification by AID results in lymphoma-associated mutations and translocations. Here, we review the recent literature on AID targeting and the role for transcriptional stalling in recruitment of this enzyme to Ig and non-Ig loci. We propose a model for AID recruitment based on transcriptional stalling, which reconciles several of the key features of SHM, CSR, and lymphoma-associated translocation.
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Affiliation(s)
- Rushad Pavri
- Laboratory of Molecular Immunology, The Rockefeller University, New York, USA
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34
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Abstract
Toll-like receptors (TLR) play a central role in the initiation of the innate immune response to pathogens. Upon recognition of molecular motifs specific for microbial molecules TLR mediate pro-inflammatory cytokine secretion and enhance antigen presentation; in B cells they further promote expansion, class switch recombination and immunoglobulin secretion. As a result of their adjuvant properties, TLR ligands have become an integral component of antimicrobial vaccines. In spite of this, little is known of the direct effects of TLR engagement on B-lymphocyte function. The scope of this review is to outline the differences in TLR expression and reactivity in murine and human B-cell subsets and to provide an overview of the currently available literature. We will further discuss the possible roles of TLR in regulating B-cell effector functions and shaping antibody-mediated defence against microbial pathogens in vivo.
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35
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Teng G, Papavasiliou FN. Long noncoding RNAs: implications for antigen receptor diversification. Adv Immunol 2009; 104:25-50. [PMID: 20457115 DOI: 10.1016/s0065-2776(08)04002-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Noncoding RNAs (ncRNAs), both small and large, have recently risen to prominence as surprisingly versatile regulators of gene expression. In fact, eukaryotic transcriptomes are rife with RNAs that do not code for protein, though the majority of these species remains wholly uncharacterized. The functional diversity among the mere handful of validated ncRNAs hints at the vast regulatory potential of these silent biomolecules. Though the act of noncoding transcription and the resultant ncRNAs do not directly produce proteins, they represent powerful means of gene control. Here we survey the accumulating literature on the myriad functions of long ncRNAs and emphasize one curious case of noncoding transcription at antigen receptor loci in lymphocytes.
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Affiliation(s)
- Grace Teng
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
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36
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Regulation of activation-induced cytidine deaminase DNA deamination activity in B-cells by Ser38 phosphorylation. Biochem Soc Trans 2009; 37:561-8. [PMID: 19442251 DOI: 10.1042/bst0370561] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Human and mouse Ig genes are diversified in mature B-cells by distinct processes known as Ig heavy-chain CSR (class switch recombination) and Ig variable-region exon SHM (somatic hypermutation). These DNA-modification processes are initiated by AID (activation-induced cytidine deaminase), a DNA cytidine deaminase predominantly expressed in activated B-cells. AID is post-transcriptionally regulated via multiple mechanisms, including microRNA regulation, nucleocytoplasmic shuttling, ubiquitination and phosphorylation. Among these regulatory processes, AID phosphorylation at Ser(38) has been a focus of particularly intense study and debate. In the present paper, we discuss recent biochemical and mouse genetic studies that begin to elucidate the functional significance of AID Ser(38) phosphorylation in the context of the evolution of this mode of AID regulation and the potential roles that it may play in activated B-cells during a normal immune response.
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37
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Takatsu K, Kouro T, Nagai Y. Interleukin 5 in the link between the innate and acquired immune response. Adv Immunol 2009; 101:191-236. [PMID: 19231596 DOI: 10.1016/s0065-2776(08)01006-7] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Interleukin-5 (IL-5) is an interdigitating homodimeric glycoprotein that is initially identified by its ability to support the in vitro growth and differentiation of mouse B cells and eosinophils. IL-5 transgenic mouse shows two predominant features, remarkable increase in B-1 cells resulting in enhanced serum antibody levels, predominantly IgM, IgA, and IgE classes and in expansion of eosinophil numbers in the blood and eosinophil infiltration into various tissues. Conversely, mice lacking a functional gene for IL-5 or IL-5 receptor alpha chain (IL-5Ralpha) display a number of developmental and functional impairments in B cells and eosinophils. IL-5 receptor (IL-5R) comprises alpha and betac chains. IL-5 specifically binds to IL-5Ralpha and induces the recruitment of betac to IL-5R. Although precise mechanisms on cell-lineage-specific IL-5Ralpha expression remain elusive, several transcription factors including Sp1, E12/E47, Oct-2, and c/EBPbeta have been shown to regulate its expression in B cells and eosinophils. JAK2 and JAK1 tyrosine kinase are constitutively associated with IL-5Ralpha and betac, respectively, and are activated by IL-5 stimulation. IL-5 activates at least three different signaling pathways including JAK2/STAT5 pathway, Btk pathway, and Ras/ERK pathway. IL-5 is one of key cytokines for mouse B cell differentiation in general, particularly for fate-determination of terminal B cell differentiation to antibody-secreting plasma cells. IL-5 critically regulates homeostatic proliferation and survival of and natural antibody production by B-1 cells, and enhances the AID and Blimp-1 expression in activated B-2 cells leading to induce mu to gamma1 class switch recombination and terminal differentiation to IgM- and IgG1-secreting plasma cells, respectively. In humans, major target cells of IL-5 are eosinophils. IL-5 appears to play important roles in pathogenesis of asthma, hypereosinophilic syndromes, and eosinophil-dependent inflammatory diseases. Clinical studies will provide a strong impetus for investigating the means of modulating IL-5 effects. We will discuss the role of IL-5 in the link between innate and acquired immune response, particularly emphasis of the molecular basis of IL-5-dependent B cell activation, allergen-induced chronic inflammation and hypereosinophilic syndromes on a novel target for therapy.
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Affiliation(s)
- Kiyoshi Takatsu
- Department of Immunobiology and Genetics, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama 930-0194, Japan
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H3 trimethyl K9 and H3 acetyl K9 chromatin modifications are associated with class switch recombination. Proc Natl Acad Sci U S A 2009; 106:5288-93. [PMID: 19276123 DOI: 10.1073/pnas.0901368106] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Class switch recombination (CSR) involves a DNA rearrangement in the Ig heavy chain (IgH) gene that allows the same variable (V) region to be expressed with any one of the downstream constant region (C) genes to encode antibodies with many different effector functions. One hypothesis for how CSR is targeted to different C region genes is that histone modifications increase accessibility and/or recruit activation-induced cytosine deaminase (AID) and its associated processes to particular donor and recipient switch regions. In this work, we identified H3 acetyl K9 and H3 trimethyl K9 as histone modifications that correlate with the recombining pair of donor and recipient switch regions. The appearance of H3 trimethyl K9 is surprising because usually it is thought to mark silent genes and heterochromatin. Nevertheless, the time course of appearance of these histone modifications, the regions in IgH they associate with, and their appearance independent of AID damage suggest that both modifications play a role in targeting CSR.
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Stavnezer J, Kang J. The surprising discovery that TGF beta specifically induces the IgA class switch. THE JOURNAL OF IMMUNOLOGY 2009; 182:5-7. [PMID: 19109126 DOI: 10.4049/jimmunol.182.1.5] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Janet Stavnezer
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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40
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Ono M, Nose M. Persistent expression of an unproductive immunoglobulin heavy chain allele with DH-JH-gamma configuration in peripheral tissues. APMIS 2008; 115:1350-6. [PMID: 18184404 DOI: 10.1111/j.1600-0463.2007.apm_870.xml.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Genomic recombination events, including VDJ recombination (VDJR) and class-switch recombination (CSR), are indispensable for the adaptation and progression of the acquired immune system. These processes are completed by orderly, temporal onsets of the gene rearrangements along with B-cell differentiation. The presence of various premature transcripts of immunoglobulin heavy chain (IgH) alleles has been demonstrated during B-cell ontogeny. These include D(H)-J(H) (DJ)-mu, J(H)-mu, and sterile transcripts of C(H). Since these transcripts can be detected during the onset of VDJR and CSR, their presence is believed to reflect a structural change in the genome, favoring VDJR and CSR. This report presents evidence of persistent DJ transcription and onset of CSR on an unproductive IgH allele in peripheral tissues. Nucleotide sequence analysis revealed that these transcripts showed DJ-gamma (Dgamma) configuration and that characteristics of the variable region were essentially the same as those of the DJ-mu transcript previously described. It was noted that the small intestine abundantly expresses Dgamma transcripts with gamma2b and gamma1 isotypes of the IgH constant region. The present findings indicate the onset of CSR preceding V(H) to DJ joining in an unproductive IgH allele of the peripheral B cell and the specificity for the gut-associated condition for B-cell differentiation in the small intestine.
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Affiliation(s)
- Masao Ono
- Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Japan.
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41
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Doi T, Obayashi K, Kadowaki T, Fujii H, Koyasu S. PI3K is a negative regulator of IgE production. Int Immunol 2008; 20:499-508. [PMID: 18303010 DOI: 10.1093/intimm/dxn009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The production of IgE, a main player in allergic disorders such as asthma and atopic dermatitis, is strictly regulated and the serum concentrations of IgE are normally kept at a much lower level than other isotypes. We found that mice deficient for the p85alpha regulatory subunit of class IA phosphoinositide 3-kinase (PI3K) produced increasing amounts of serum IgE. Purified p85alpha-/- B cells produced more IgE than wild-type B cells in vitro in response to anti-CD40 mAb and IL-4. PI3K inhibitors wortmannin and IC87114 enhanced IgE production by wild-type B cells stimulated with anti-CD40 mAb and IL-4. Under the same condition, antigen receptor cross-linking induced the expression of inhibitor of differentiation-2 and suppressed the expression of activation-induced cytidine deaminase and class switch recombination (CSR) in a PI3K-dependent manner. IgE production was also suppressed in a concentrated cell culture condition, which was completely reversed by PI3K inhibition. The selective suppression of IgE production by PI3K was also observed at a protein level after CSR. Our results indicate that PI3K negatively regulates IgE production at both CSR and protein levels.
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Affiliation(s)
- Tomomitsu Doi
- Department of Microbiology and Immunology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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Chaudhuri J, Basu U, Zarrin A, Yan C, Franco S, Perlot T, Vuong B, Wang J, Phan RT, Datta A, Manis J, Alt FW. Evolution of the Immunoglobulin Heavy Chain Class Switch Recombination Mechanism. Adv Immunol 2007; 94:157-214. [PMID: 17560275 DOI: 10.1016/s0065-2776(06)94006-1] [Citation(s) in RCA: 195] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
To mount an optimum immune response, mature B lymphocytes can change the class of expressed antibody from IgM to IgG, IgA, or IgE through a recombination/deletion process termed immunoglobulin heavy chain (IgH) class switch recombination (CSR). CSR requires the activation-induced cytidine deaminase (AID), which has been shown to employ single-stranded DNA as a substrate in vitro. IgH CSR occurs within and requires large, repetitive sequences, termed S regions, which are parts of germ line transcription units (termed "C(H) genes") that are composed of promoters, S regions, and individual IgH constant region exons. CSR requires and is directed by germ line transcription of participating C(H) genes prior to CSR. AID deamination of cytidines in S regions appears to lead to S region double-stranded breaks (DSBs) required to initiate CSR. Joining of two broken S regions to complete CSR exploits the activities of general DNA DSB repair mechanisms. In this chapter, we discuss our current knowledge of the function of S regions, germ line transcription, AID, and DNA repair in CSR. We present a model for CSR in which transcription through S regions provides DNA substrates on which AID can generate DSB-inducing lesions. We also discuss how phosphorylation of AID may mediate interactions with cofactors that facilitate access to transcribed S regions during CSR and transcribed variable regions during the related process of somatic hypermutation (SHM). Finally, in the context of this CSR model, we further discuss current findings that suggest synapsis and joining of S region DSBs during CSR have evolved to exploit general mechanisms that function to join widely separated chromosomal DSBs.
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Affiliation(s)
- Jayanta Chaudhuri
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
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Xue K, Rada C, Neuberger MS. The in vivo pattern of AID targeting to immunoglobulin switch regions deduced from mutation spectra in msh2-/- ung-/- mice. ACTA ACUST UNITED AC 2006; 203:2085-94. [PMID: 16894013 PMCID: PMC2118391 DOI: 10.1084/jem.20061067] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Immunoglobulin (Ig) class switching is initiated by deamination of C→U within the immunoglobulin heavy chain locus, catalyzed by activation-induced deaminase (AID). In the absence of uracil-DNA glycosylase (UNG) and the homologue of bacterial MutS (MSH)–2 mismatch recognition protein, the resultant U:G lesions are not processed into switching events but are fixed by replication allowing sites of AID-catalyzed deamination to be identified by the resulting C→T mutations. We find that AID targets cytosines in both donor and acceptor switch regions (S regions) with the deamination domains initiating ∼150 nucleotides 3′ of the I exon start sites and extending over several kilobases (the IgH intronic enhancer is spared). Culturing B cells with interleukin 4 or interferon γ specifically enhanced deamination around Sγ1 and Sγ2a, respectively. Mutation spectra suggest that, in the absence of UNG and MSH2, AID may occasionally act at the μ switch region in an apparently processive manner, but there is no marked preference for targeting of the transcribed versus nontranscribed strand (even in areas capable of R loop formation). The data are consistent with switch recombination being triggered by transcription-associated, strand-symmetric AID-mediated deamination at both donor and acceptor S regions with cytokines directing isotype specificity by potentiating AID recruitment to the relevant acceptor S region.
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Affiliation(s)
- Kanmin Xue
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 2QH, UK
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SZÉPFALUSI Z, NENTWICH I, GERSTMAYR M, JOST E, TODORAN L, GRATZL R, HERKNER K, URBANEK R. Prenatal allergen contact with milk proteins. Clin Exp Allergy 2006. [DOI: 10.1111/j.1365-2222.1997.tb00669.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Dryer RL, Covey LR. Use of chromatin immunoprecipitation (ChIP) to detect transcription factor binding to highly homologous promoters in chromatin isolated from unstimulated and activated primary human B cells. Biol Proced Online 2006; 8:44-54. [PMID: 16799696 PMCID: PMC1455481 DOI: 10.1251/bpo117] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 03/28/2006] [Accepted: 03/29/2006] [Indexed: 11/23/2022] Open
Abstract
The Chromatin Immunoprecipiation (ChIP) provides a powerful technique for identifying the in vivo association of transcription factors with regulatory elements. However, obtaining meaningful information for promoter interactions is extremely challenging when the promoter is a member of a class of highly homologous elements. Use of PCR primers with small numbers of mutations can limit cross-hybridization with non-targeted sequences and distinguish a pattern of binding for factors with the regulatory element of interest. In this report, we demonstrate the selective in vivo association of NF-κB, p300 and CREB with the human Iγ1 promoter located in the intronic region upstream of the Cγ1 exons in the immunoglobulin heavy chain locus. These methods have the ability to extend ChIP analysis to promoters with a high degree of homology.
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Affiliation(s)
- Rebecca L. Dryer
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey. USA
| | - Lori R. Covey
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey. USA
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Qin X, Tang H. Differential regulation of chromatin structure of the murine 3′ IgH enhancer and IgG2b germline promoter in response to lipopolysaccharide and CD40 signaling. Mol Immunol 2006; 43:1211-20. [PMID: 16099047 DOI: 10.1016/j.molimm.2005.07.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Indexed: 11/22/2022]
Abstract
Class switch recombination (CSR) of murine immunoglobulin heavy chain (IgH) is controlled by germline transcription-coupled modification of the accessibility of the highly repetitive switch regions (S) located upstream of the constant region genes. Activation of the 3' IgH enhancer (3'E) is believed to regulate CSR during B cell terminal differentiation, although the detailed molecular mechanism remains unclear. Here, we show that BAF57 and BRG1, two essential subunits of murine SWI/SNF complex, differentially associate with the DNase I hypersensitive region HS1/2 of 3'E and the IgG2b germline promoter in response to LPS activation or CD40 engagement. Both LPS and CD40 signaling cause SWI/SNF complex to dissociate from HS1/2 and associate with their responsive IgG2b germline promoter, suggesting the potential fluidity of chromatin structure and specific regulatory mode for the ATP-dependent chromatin remodeler during CSR. More interesting, increase in histone acetylation is either inverse or parallel with the action of SWI/SNF complex at HS1/2 enhancer or IgG2b germline promoter, respectively. Chromatin immunoprecipitation experiments show that alteration of histone H3 and H4 acetylation has overall similarities in response to LPS and CD40 signaling, with H3 hyperacetylated and H4 hypoacetylated at the HS1/2 enhancer and reversed modification patterns at the IgG2b germline promoter. Finally, the specificity of LPS and CD40 signaling in control of CSR could be partially coded by the specific acetylation marking of H3 and H4. Our results further strengthen the notion that chromatin remodeling plays a critical role in CSR.
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Affiliation(s)
- Xincheng Qin
- The Center for Molecular Microbiology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, China
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Deenick EK, Hasbold J, Hodgkin PD. Decision criteria for resolving isotype switching conflicts by B cells. Eur J Immunol 2005; 35:2949-55. [PMID: 16180247 DOI: 10.1002/eji.200425719] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Isotype switching by B cells is highly regulated by a group of cytokines including IL-4, IFN-gamma and TGF-beta. A B cell can only express one isotype at a time; however, during an immune response it may be exposed to combinations of stimuli that provide it with conflicting switching instructions. To determine how such cytokine-induced isotype switch conflicts would be resolved, the responses of B cells exposed to multiple cytokines were investigated. To eliminate complications arising from simultaneous effects of switching cytokines on proliferation, division number was used as a reference framework to monitor switching rate. The results show a clear hierarchy in which IFN-gamma is dominant over IL-4, and both IL-4 and IFN-gamma are dominant over TGF-beta. These studies reveal how B cells possess a set of logical decision criteria for dealing with pathogens that invoke a range of different stimuli.
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Affiliation(s)
- Elissa K Deenick
- Immune Regulation Group, Centenary Institute of Cancer Medicine and Cell Biology, Newtown, Australia
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Park SR, Seo GY, Choi AJ, Stavnezer J, Kim PH. Analysis of transforming growth factor-beta1-induced Ig germ-line gamma2b transcription and its implication for IgA isotype switching. Eur J Immunol 2005; 35:946-56. [PMID: 15688346 DOI: 10.1002/eji.200425848] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Transforming growth factor (TGF)-beta1 directs class switch recombination (CSR) to IgG2b as well as to IgA. Smad3/4, Runx3 and p300 mediate TGF-beta1-induced germ-line (GL) alpha transcription leading to IgA expression. However, the molecular mechanisms by which TGF-beta1 induces IgG2b CSR are unknown. We used luciferase reporter plasmids to investigate how TGF-beta1 regulates the activity of the promoter for GL transcripts of IgG2b constant gene (GLgamma2b promoter). Similarly to the GLalpha promoter, overexpression of Smad3/4 and Runx3 enhances TGF-beta1-induced GLgamma2b promoter activity. Mutation analysis of the promoter identified likely Smad- and Runx3-binding sites. Also similar to the GLalpha promoter, overexpression of p300 enhances Smad3/4-mediated promoter activity, whereas E1A represses promoter activity. Since these regulation mechanisms underlying both GLalpha and GLgamma2b transcription are similar, we explored the possibility that TGF-beta1 induces IgA CSR via transitional IgG2b CSR. TGF-beta1 enhances the expression of both Ialpha-Cmu and Ialpha-Cgamma2b circle transcripts, indicative of direct (Smu-->Salpha) and sequential CSR (Smu-->Sgamma2b-->Salpha).
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Affiliation(s)
- Seok-Rae Park
- Department of Microbiology, College of Natural Sciences, Kangwon National University, Chunchon, S.Korea
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Abstract
This review discusses evolution of the process of Ig heavy chain class switching, relating it to the first appearance of somatic hypermutation (SHM) of variable region genes. First, we discuss recent findings on the mechanism of class switch recombination (CSR) in mice and humans, and then review the mechanisms of expression of Ig heavy chain isotypes from fishes to mammals. Importantly, activation-induced cytidine deaminase (AID), which is essential for CSR and somatic hypermutation, is found in fishes. Although at least some fishes are likely to undergo SHM, CSR is highly unlikely to occur in this group. We discuss the first appearance of CSR in amphibians and how it differs in birds and mammals.
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Affiliation(s)
- Janet Stavnezer
- Department of Molecular Genetics and Microbiology, Program in Immunology and Virology, University of Massachusetts Medical School, 55 Lake Ave N, Worcester, MA 01655-0122, USA.
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Abstract
A functional immune system is one of the prerequisites for the survival of a species. Humans have one of the most complicated immune systems, with the ability to learn from and adapt to pathogens. At first, a primary repertoire of antibodies is generated, which, upon antigen encounter, will diversify and adapt to produce a highly specific and potent secondary response, part of which is kept in memory to fight off future infections. In this review, the mechanism as well as the specificities of the key protein in the secondary immune response, activation-induced cytidine deaminase (AID), are highlighted, as well as its role in the DNA deamination model of immunoglobulin diversification. The review also highlights aspects of AID's regulation on both the transcriptional as well as post-translational level and its potential molecular mechanism and specificity. Furthermore, it expands outside the involvement of AID in somatic hypermutation, class switching, and gene conversion to discuss the implications of DNA deamination in epigenetic modifications of DNA (as a potential demethylase), the induction of mutations during oncogenesis, and includes an evolutionary comparison to the DNA deaminase family member APOBEC3G, a key protein in human immunodeficiency virus pathogenesis.
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Affiliation(s)
- Svend Petersen-Mahrt
- DNA Editing Laboratory, Cancer Research UK, Clare Hall Laboratories, South Mimms Hert, UK.
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