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Abstract
The evolution of IgE in mammals added an extra layer of immune protection at body surfaces to provide a rapid and local response against antigens from the environment. The IgE immune response employs potent expulsive and inflammatory forces against local antigen provocation, at the risk of damaging host tissues and causing allergic disease. Two well-known IgE receptors, the high-affinity FcεRI and low-affinity CD23, mediate the activities of IgE. Unlike other known antibody receptors, CD23 also regulates IgE expression, maintaining IgE homeostasis. This mechanism evolved by adapting the function of the complement receptor CD21. Recent insights into the dynamic character of IgE structure, its resultant capacity for allosteric modulation, and the potential for ligand-induced dissociation have revealed previously unappreciated mechanisms for regulation of IgE and IgE complexes. We describe recent research, highlighting structural studies of the IgE network of proteins to analyze the uniquely versatile activities of IgE and anti-IgE biologics.
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Affiliation(s)
- J M McDonnell
- Randall Centre for Cell and Molecular Biophysics and School of Basic and Medical Biosciences, King's College London, London, UK; , ,
| | | | - B J Sutton
- Randall Centre for Cell and Molecular Biophysics and School of Basic and Medical Biosciences, King's College London, London, UK; , ,
| | - H J Gould
- Randall Centre for Cell and Molecular Biophysics and School of Basic and Medical Biosciences, King's College London, London, UK; , ,
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Phua SX, Chan KF, Su CTT, Poh JJ, Gan SKE. Perspective: The promises of a holistic view of proteins-impact on antibody engineering and drug discovery. Biosci Rep 2019; 39:BSR20181958. [PMID: 30630879 PMCID: PMC6398899 DOI: 10.1042/bsr20181958] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 12/27/2018] [Accepted: 01/09/2019] [Indexed: 12/23/2022] Open
Abstract
The reductionist approach is prevalent in biomedical science. However, increasing evidence now shows that biological systems cannot be simply considered as the sum of its parts. With experimental, technological, and computational advances, we can now do more than view parts in isolation, thus we propose that an increasing holistic view (where a protein is investigated as much as a whole as possible) is now timely. To further advocate this, we review and discuss several studies and applications involving allostery, where distant protein regions can cross-talk to influence functionality. Therefore, we believe that an increasing big picture approach holds great promise, particularly in the areas of antibody engineering and drug discovery in rational drug design.
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Affiliation(s)
- Ser-Xian Phua
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Kwok-Fong Chan
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Chinh Tran-To Su
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Jun-Jie Poh
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
- APD SKEG Pte Ltd, Singapore
| | - Samuel Ken-En Gan
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore
- APD SKEG Pte Ltd, Singapore
- p53 Laboratory, Agency for Science, Technology and Research (A*STAR), Singapore
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Ward DE, Fay BL, Adejuwon A, Han H, Ma Z. Chimeric Antigen Receptors Based on Low Affinity Mutants of FcεRI Re-direct T Cell Specificity to Cells Expressing Membrane IgE. Front Immunol 2018; 9:2231. [PMID: 30364107 PMCID: PMC6191488 DOI: 10.3389/fimmu.2018.02231] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 09/07/2018] [Indexed: 12/31/2022] Open
Abstract
IgE is the key mediator of allergic responses. Omalizumab, an IgE-specific monoclonal antibody that depletes IgE, is effective for treating severe allergic asthma. The need for frequent administration of the expensive drug, however, limits its applications. Taking advantage of T cell memory, adoptive T cell therapy (ACT) targeting IgE-producing cells has the potential to achieve long-term suppression of IgE and relief of symptoms for severe allergic diseases. The transmembrane form of IgE (mIgE), which is present on all IgE-producing cells, serves as an excellent molecular target for ACT that employs chimeric antigen receptors (CARs). Here, we designed and tested CARs that use the extracellular domain of high affinity IgE receptor, FcεRIα, for mIgE recognition. When expressed on Jurkat T cells, FcεRIα-based CARs mediated robust responses in terms of CD69 upregulation to U266 myeloma cells expressing low levels of mIgE. FcεRIα-based CARs specifically recognized cells expressing mIgE, but not cells with secreted IgE captured through Fcε receptors. CAR+ Jurkat cells did not respond to LAD2 mast cells with secreted IgE bound through FcεRI or Ramos cells with secreted IgE bound through FcεRII. Co-culture of CAR+ Jurkat cells and LAD2 mast cells with IgE bound did not trigger LAD2 cell degranulation. The activity of CAR using wild type FcεRIα for mIgE binding was inhibited by the presence secreted IgE, which likely blocked CAR-mIgE interaction. The activities of CARs using low affinity mutants of FcεRIα, however, tolerated secreted IgE at relatively high concentrations. Moreover, primary human CD8+ T cells expressing a low affinity mutant CAR responded to U266 cells with INFγ production and cytotoxicity despite the presence of secreted IgE. The potency, specificity, and robustness of our CAR design, combined with repaid advances in the safety of ACT, hold promise for novel and highly effective cell-based therapies against severe allergic diseases.
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Affiliation(s)
- Dana E Ward
- Department of Biomedical Research, Nemours/A.I. duPont Hospital for Children, Wilmington, DE, United States
| | - Brittany L Fay
- Department of Biomedical Research, Nemours/A.I. duPont Hospital for Children, Wilmington, DE, United States
| | - Adebomi Adejuwon
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
| | - Huihui Han
- Department of Biomedical Research, Nemours/A.I. duPont Hospital for Children, Wilmington, DE, United States
| | - Zhengyu Ma
- Department of Biomedical Research, Nemours/A.I. duPont Hospital for Children, Wilmington, DE, United States
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Eicher JD, Chami N, Kacprowski T, Nomura A, Chen MH, Yanek LR, Tajuddin SM, Schick UM, Slater AJ, Pankratz N, Polfus L, Schurmann C, Giri A, Brody JA, Lange LA, Manichaikul A, Hill WD, Pazoki R, Elliot P, Evangelou E, Tzoulaki I, Gao H, Vergnaud AC, Mathias RA, Becker DM, Becker LC, Burt A, Crosslin DR, Lyytikäinen LP, Nikus K, Hernesniemi J, Kähönen M, Raitoharju E, Mononen N, Raitakari OT, Lehtimäki T, Cushman M, Zakai NA, Nickerson DA, Raffield LM, Quarells R, Willer CJ, Peloso GM, Abecasis GR, Liu DJ, Deloukas P, Samani NJ, Schunkert H, Erdmann J, Fornage M, Richard M, Tardif JC, Rioux JD, Dube MP, de Denus S, Lu Y, Bottinger EP, Loos RJF, Smith AV, Harris TB, Launer LJ, Gudnason V, Velez Edwards DR, Torstenson ES, Liu Y, Tracy RP, Rotter JI, Rich SS, Highland HM, Boerwinkle E, Li J, Lange E, Wilson JG, Mihailov E, Mägi R, Hirschhorn J, Metspalu A, Esko T, Vacchi-Suzzi C, Nalls MA, Zonderman AB, Evans MK, Engström G, Orho-Melander M, Melander O, O'Donoghue ML, Waterworth DM, Wallentin L, White HD, Floyd JS, Bartz TM, Rice KM, Psaty BM, Starr JM, Liewald DCM, Hayward C, Deary IJ, Greinacher A, Völker U, Thiele T, Völzke H, van Rooij FJA, Uitterlinden AG, Franco OH, Dehghan A, Edwards TL, Ganesh SK, Kathiresan S, Faraday N, Auer PL, Reiner AP, Lettre G, Johnson AD. Platelet-Related Variants Identified by Exomechip Meta-analysis in 157,293 Individuals. Am J Hum Genet 2016; 99:40-55. [PMID: 27346686 PMCID: PMC5005441 DOI: 10.1016/j.ajhg.2016.05.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/03/2016] [Indexed: 12/13/2022] Open
Abstract
Platelet production, maintenance, and clearance are tightly controlled processes indicative of platelets' important roles in hemostasis and thrombosis. Platelets are common targets for primary and secondary prevention of several conditions. They are monitored clinically by complete blood counts, specifically with measurements of platelet count (PLT) and mean platelet volume (MPV). Identifying genetic effects on PLT and MPV can provide mechanistic insights into platelet biology and their role in disease. Therefore, we formed the Blood Cell Consortium (BCX) to perform a large-scale meta-analysis of Exomechip association results for PLT and MPV in 157,293 and 57,617 individuals, respectively. Using the low-frequency/rare coding variant-enriched Exomechip genotyping array, we sought to identify genetic variants associated with PLT and MPV. In addition to confirming 47 known PLT and 20 known MPV associations, we identified 32 PLT and 18 MPV associations not previously observed in the literature across the allele frequency spectrum, including rare large effect (FCER1A), low-frequency (IQGAP2, MAP1A, LY75), and common (ZMIZ2, SMG6, PEAR1, ARFGAP3/PACSIN2) variants. Several variants associated with PLT/MPV (PEAR1, MRVI1, PTGES3) were also associated with platelet reactivity. In concurrent BCX analyses, there was overlap of platelet-associated variants with red (MAP1A, TMPRSS6, ZMIZ2) and white (PEAR1, ZMIZ2, LY75) blood cell traits, suggesting common regulatory pathways with shared genetic architecture among these hematopoietic lineages. Our large-scale Exomechip analyses identified previously undocumented associations with platelet traits and further indicate that several complex quantitative hematological, lipid, and cardiovascular traits share genetic factors.
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Affiliation(s)
- John D Eicher
- Population Sciences Branch, National Heart Lung and Blood Institute, The Framingham Heart Study, Framingham, MA 01702, USA
| | - Nathalie Chami
- Department of Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada; Montreal Heart Institute, Montréal, QC H1T 1C8, Canada
| | - Tim Kacprowski
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald and Ernst-Mortiz-Arndt University Greifswald, Greifswald 17475, Germany; DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
| | - Akihiro Nomura
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA 02142, USA; Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa, Ishikawa 9200942, Japan
| | - Ming-Huei Chen
- Population Sciences Branch, National Heart Lung and Blood Institute, The Framingham Heart Study, Framingham, MA 01702, USA
| | - Lisa R Yanek
- Department of Medicine, Division of General Internal Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Salman M Tajuddin
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Ursula M Schick
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Genetics of Obesity and Related Metabolic Traits Program, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Andrew J Slater
- Genetics, Target Sciences, GlaxoSmithKline, Research Triangle Park, NC 27709, USA; OmicSoft Corporation, Cary, NC 27513, USA
| | - Nathan Pankratz
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55454, USA
| | - Linda Polfus
- Human Genetics Center, School of Public Health, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Claudia Schurmann
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; The Genetics of Obesity and Related Metabolic Traits Program, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ayush Giri
- Division of Epidemiology, Institute for Medicine and Public Health, Vanderbilt University, Nashville, TN 37235, USA
| | - Jennifer A Brody
- Department of Medicine, University of Washington, Seattle, WA 98101, USA
| | - Leslie A Lange
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27514, USA
| | - Ani Manichaikul
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA 22908, USA
| | - W David Hill
- Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh EH8 9JZ, UK; Department of Psychology, University of Edinburgh, Edinburgh EH8 9JZ, UK
| | - Raha Pazoki
- Department of Epidemiology, Erasmus MC, Rotterdam 3000, the Netherlands
| | - Paul Elliot
- Department of Epidemiology and Biostatistics, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Evangelos Evangelou
- Department of Epidemiology and Biostatistics, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London W2 1PG, UK; Department of Hygiene and Epidemiology, University of Ioannina Medical School, Ioannina 45110, Greece
| | - Ioanna Tzoulaki
- Department of Epidemiology and Biostatistics, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London W2 1PG, UK; Department of Hygiene and Epidemiology, University of Ioannina Medical School, Ioannina 45110, Greece
| | - He Gao
- Department of Epidemiology and Biostatistics, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Anne-Claire Vergnaud
- Department of Epidemiology and Biostatistics, MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Rasika A Mathias
- Department of Medicine, Division of General Internal Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Divisions of Allergy and Clinical Immunology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Diane M Becker
- Department of Medicine, Division of General Internal Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Lewis C Becker
- Department of Medicine, Division of General Internal Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Divisions of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Amber Burt
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - David R Crosslin
- Department of Biomedical Informatics and Medical Education, University of Washington, Seattle, WA 98105, USA
| | - Leo-Pekka Lyytikäinen
- Department of Clinical Chemistry, Fimlab Laboratories, Tampere 33520, Finland; Department of Clinical Chemistry, University of Tampere School of Medicine, Tampere 33514, Finland
| | - Kjell Nikus
- Department of Cardiology, Heart Center, Tampere University Hospital, Tampere 33521, Finland; University of Tampere, School of Medicine, Tampere 33514, Finland
| | - Jussi Hernesniemi
- Department of Clinical Chemistry, Fimlab Laboratories, Tampere 33520, Finland; Department of Clinical Chemistry, University of Tampere School of Medicine, Tampere 33514, Finland; Department of Cardiology, Heart Center, Tampere University Hospital, Tampere 33521, Finland
| | - Mika Kähönen
- Department of Clinical Physiology, Tampere University Hospital, Tampere 33521, Finland; Department of Clinical Physiology, University of Tampere, Tampere 33514, Finland
| | - Emma Raitoharju
- Department of Clinical Chemistry, Fimlab Laboratories, Tampere 33520, Finland; Department of Clinical Chemistry, University of Tampere School of Medicine, Tampere 33514, Finland
| | - Nina Mononen
- Department of Clinical Chemistry, Fimlab Laboratories, Tampere 33520, Finland; Department of Clinical Chemistry, University of Tampere School of Medicine, Tampere 33514, Finland
| | - Olli T Raitakari
- Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital, Turku 20521, Finland; Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku, Turku 20520, Finland
| | - Terho Lehtimäki
- Department of Clinical Chemistry, Fimlab Laboratories, Tampere 33520, Finland; Department of Clinical Chemistry, University of Tampere School of Medicine, Tampere 33514, Finland
| | - Mary Cushman
- Departments of Medicine and Pathology, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Neil A Zakai
- Departments of Medicine and Pathology, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Deborah A Nickerson
- Department of Genome Sciences, University of Washington, Seattle, WA 98105, USA
| | - Laura M Raffield
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27514, USA
| | - Rakale Quarells
- Morehouse School of Medicine, Social Epidemiology Research Center, Cardiovascular Research Institute, Atlanta, GA 30310, USA
| | - Cristen J Willer
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48108, USA; Department of Computational Medicine and Bioinformatics, Department of Human Genetics, University of Michigan, Ann Arbor, MI 48108, USA; Department of Biostatistics, University of Michigan, Ann Arbor, MI 48108, USA
| | - Gina M Peloso
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA 02142, USA; Department of Biostatistics, Boston University School of Public Health, Boston, MA 02118, USA
| | - Goncalo R Abecasis
- Center for Statistical Genetics, Department of Biostatistics, University of Michigan, Ann Arbor, MI 48108, USA
| | - Dajiang J Liu
- Department of Public Health Sciences, College of Medicine, Pennsylvania State University, Hershey, PA 17033, USA
| | - Panos Deloukas
- William Harvey Research Institute, Queen Mary University London, London E1 4NS, UK; Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders (PACER-HD), King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Nilesh J Samani
- Department of Cardiovascular Sciences, University of Leicester, Leicester LE1 7RH, UK; NIHR Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, Leicester LE3 9QP, UK
| | - Heribert Schunkert
- DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich 80333, Germany; Deutsches Herzzentrum München, Technische Universität München, Munich 80333, Germany
| | - Jeanette Erdmann
- Institute for Integrative and Experimental Genomics, University of Lübeck, Lübeck 23562, Germany; DZHK (German Research Centre for Cardiovascular Research), partner site Hamburg/Lübeck/Kiel, Lübeck 23562, Germany
| | - Myriam Fornage
- Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Melissa Richard
- Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Jean-Claude Tardif
- Department of Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada; Montreal Heart Institute, Montréal, QC H1T 1C8, Canada
| | - John D Rioux
- Department of Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada; Montreal Heart Institute, Montréal, QC H1T 1C8, Canada
| | - Marie-Pierre Dube
- Department of Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada; Montreal Heart Institute, Montréal, QC H1T 1C8, Canada
| | - Simon de Denus
- Montreal Heart Institute, Montréal, QC H1T 1C8, Canada; Faculty of Pharmacy, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Yingchang Lu
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Erwin P Bottinger
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ruth J F Loos
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Albert Vernon Smith
- Icelandic Heart Association, Kopavogur 201, Iceland; Faculty of Medicine, University of Iceland, Reykjavik 101, Iceland
| | - Tamara B Harris
- Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, Intramural Research Program, NIH, Bethesda, MD 21224, USA
| | - Lenore J Launer
- Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, Intramural Research Program, NIH, Bethesda, MD 21224, USA
| | - Vilmundur Gudnason
- Icelandic Heart Association, Kopavogur 201, Iceland; Faculty of Medicine, University of Iceland, Reykjavik 101, Iceland
| | - Digna R Velez Edwards
- Vanderbilt Epidemiology Center, Department of Obstetrics & Gynecology, Institute for Medicine and Public Health, Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN 37203, USA
| | - Eric S Torstenson
- Division of Epidemiology, Institute for Medicine and Public Health, Vanderbilt University, Nashville, TN 37235, USA
| | - Yongmei Liu
- Center for Human Genetics, Division of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Russell P Tracy
- Departments of Pathology and Laboratory Medicine and Biochemistry, University of Vermont College of Medicine, Colchester, VT 05446, USA
| | - Jerome I Rotter
- Institute for Translational Genomics and Population Sciences, Los Angeles Biomedical Research Institute, Torrance, CA 90502, USA; Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Stephen S Rich
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA 22908, USA
| | - Heather M Highland
- The University of Texas School of Public Health, The University of Texas Graduate School of Biomedical Sciences at Houston, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; Department of Epidemiology, University of North Carolina, Chapel Hill, NC 27514, USA
| | - Eric Boerwinkle
- Human Genetics Center, School of Public Health, University of Texas Health Science Center at Houston, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jin Li
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Palo Alto, CA 94305, USA
| | - Ethan Lange
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27514, USA; Department of Biostatistics, University of North Carolina, Chapel Hill, NC 27514, USA
| | - James G Wilson
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Evelin Mihailov
- Estonian Genome Center, University of Tartu, Tartu 51010, Estonia
| | - Reedik Mägi
- Estonian Genome Center, University of Tartu, Tartu 51010, Estonia
| | - Joel Hirschhorn
- Program in Medical and Population Genetics, Broad Institute, Cambridge, MA 02142, USA; Department of Endocrinology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Andres Metspalu
- Estonian Genome Center, University of Tartu, Tartu 51010, Estonia
| | - Tõnu Esko
- Program in Medical and Population Genetics, Broad Institute, Cambridge, MA 02142, USA; Estonian Genome Center, University of Tartu, Tartu 51010, Estonia
| | - Caterina Vacchi-Suzzi
- Department of Family, Population and Preventive Medicine, Stony Brook University, Stony Brook, NY 11794, USA
| | - Mike A Nalls
- Laboratory of Neurogenetics, National Institute on Aging, NIH, Bethesda, MD 21224, USA
| | - Alan B Zonderman
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Michele K Evans
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Gunnar Engström
- Department of Clinical Sciences Malmö, Lund University, Malmö 221 00, Sweden; Skåne University Hospital, Malmö 222 41, Sweden
| | - Marju Orho-Melander
- Department of Clinical Sciences Malmö, Lund University, Malmö 221 00, Sweden; Skåne University Hospital, Malmö 222 41, Sweden
| | - Olle Melander
- Department of Clinical Sciences Malmö, Lund University, Malmö 221 00, Sweden; Skåne University Hospital, Malmö 222 41, Sweden
| | - Michelle L O'Donoghue
- TIMI Study Group, Cardiovascular Division, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Dawn M Waterworth
- Genetics, Target Sciences, GlaxoSmithKline, King of Prussia, PA 19406, USA
| | - Lars Wallentin
- Department of Medical Sciences, Cardiology, and Uppsala Clinical Research Center, Uppsala University, Uppsala 751 85, Sweden
| | - Harvey D White
- Green Lane Cardiovascular Service, Auckland City Hospital and University of Auckland, Auckland 1142, New Zealand
| | - James S Floyd
- Department of Medicine, University of Washington, Seattle, WA 98101, USA
| | - Traci M Bartz
- Department of Biostatistics, University of Washington, Seattle, WA 98195, USA
| | - Kenneth M Rice
- Department of Biostatistics, University of Washington, Seattle, WA 98195, USA
| | - Bruce M Psaty
- Cardiovascular Health Research Unit, Departments of Medicine, Epidemiology and Health Services, University of Washington, Seattle, WA 98101, USA; Group Health Research Institute, Group Health Cooperative, Seattle, WA 98101, USA
| | - J M Starr
- Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh EH8 9JZ, UK; Alzheimer Scotland Research Centre, Edinburgh EH8 9JZ, UK
| | - David C M Liewald
- Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh EH8 9JZ, UK; Department of Psychology, University of Edinburgh, Edinburgh EH8 9JZ, UK
| | - Caroline Hayward
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Ian J Deary
- Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh EH8 9JZ, UK; Department of Psychology, University of Edinburgh, Edinburgh EH8 9JZ, UK
| | - Andreas Greinacher
- Institute for Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald 17475, Germany
| | - Uwe Völker
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald and Ernst-Mortiz-Arndt University Greifswald, Greifswald 17475, Germany; DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
| | - Thomas Thiele
- Institute for Immunology and Transfusion Medicine, University Medicine Greifswald, Greifswald 17475, Germany
| | - Henry Völzke
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany; Institute for Community Medicine, University Medicine Greifswald, Greifswald 13347, Germany
| | | | - André G Uitterlinden
- Department of Epidemiology, Erasmus MC, Rotterdam 3000, the Netherlands; Department of Internal Medicine, Erasmus MC, Rotterdam 3000, the Netherlands; Netherlands Consortium for Healthy Ageing (NCHA), Rotterdam 3015, the Netherlands
| | - Oscar H Franco
- Department of Epidemiology, Erasmus MC, Rotterdam 3000, the Netherlands
| | - Abbas Dehghan
- Department of Epidemiology, Erasmus MC, Rotterdam 3000, the Netherlands
| | - Todd L Edwards
- Division of Epidemiology, Institute for Medicine and Public Health, Vanderbilt University, Nashville, TN 37235, USA
| | - Santhi K Ganesh
- Departments of Internal and Human Genetics, University of Michigan, Ann Arbor, MI 48108, USA
| | - Sekar Kathiresan
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA 02142, USA; Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Nauder Faraday
- Department of Anesthesiology & Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Paul L Auer
- Zilber School of Public Health, University of Wisconsin-Milwaukee, Milwaukee, WI 53205, USA
| | - Alex P Reiner
- Department of Epidemiology, University of Washington, Seattle, WA 98105, USA; Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Guillaume Lettre
- Department of Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada; Montreal Heart Institute, Montréal, QC H1T 1C8, Canada
| | - Andrew D Johnson
- Population Sciences Branch, National Heart Lung and Blood Institute, The Framingham Heart Study, Framingham, MA 01702, USA.
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Huang FY, Wang CC, Huang YH, Zhao HG, Guo JL, Zhou SL, Wang H, Lin YY, Tan GH. Antigen 43/Fcε3 chimeric protein expressed by a novel bacterial surface expression system as an effective asthma vaccine. Immunology 2014; 143:230-40. [PMID: 24750112 DOI: 10.1111/imm.12302] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 04/07/2014] [Accepted: 04/15/2014] [Indexed: 12/29/2022] Open
Abstract
The IgE Fcε3 domain is an active immunotherapeutic target for asthma and other allergic diseases. However, previous methods for preparing IgE fusion protein vaccines are complex. Antigen 43 (Ag43) is a surface protein found in Escherichia coli that contains α and β subunits (the α subunit contains multiple T epitopes). Here we constructed a novel Ag43 surface display system (Ag43 system) to express Ag43 chimeric proteins to disrupt immune tolerance against IgE. The Ag43 system was constructed from the E. coli strain Tan109, in which the Ag43 gene was deleted and a recombinant plasmid (pETAg43) expressing a partial Ag43 gene was introduced. The Fcε3 domain of the IgE gene was then subcloned into plasmid pETAg43, resulting in a recombinant plasmid pETAg43/Fcε3, which was used to transform Tan109 for Ag43/Fcε3 surface expression. Thereafter, Ag43/Fcε3 was investigated as an asthma vaccine in a mouse model. Ag43/Fcε3 was expressed on and could be separated from the bacterial surface by heating to 60° while retaining activity. Ag43/Fcε3, as a protein vaccine, produced neutralizing autoantibodies to murine IgE, induced significant anti-asthma effects, and regulated IgE and T helper cytokines in a murine asthma model. Data show that Ag43/Fcε3 chimeric protein is a potential model vaccine for asthma treatment, and that the Ag43 system may be an effective tool for novel vaccine preparation to break immune tolerance to other self-molecules.
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Affiliation(s)
- Feng-Ying Huang
- Hainan Provincial Key Laboratory of Tropical Medicine, Hainan Medical College, Haikou, China
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7
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Smith LD, Leatherbarrow RJ, Spivey AC. Development of small molecules to target the IgE:FcεRI protein-protein interaction in allergies. Future Med Chem 2013; 5:1423-35. [PMID: 23919552 DOI: 10.4155/fmc.13.112] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The protein-protein interaction (PPI) between IgE and its high-affinity receptor (FcεRI) is a key component of the allergic response. Inhibiting the IgE:FcεRI PPI is an attractive strategy for therapeutic intervention and the development of allergy treatments. This PPI has been validated as a viable target by the monoclonal anti-IgE antibody omalizumab (Xolair(®)), which has demonstrated clinical efficacy when prescribed to treat moderate-to-severe asthma and hay fever, but small molecules would be a more convenient form of treatment. Cyclic peptides, small proteins and a natural product have all been developed to target the IgE:FcεRI PPI, and these will be discussed in this review. Targeting the IgE:FcεRI complex with small molecules presents various challenges, some of which are inherent in all PPI targets but some of which are unique to this system, which presents great opportunities for the development of new therapeutics for the treatment of allergies.
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8
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Saul L, Josephs DH, Cutler K, Bradwell A, Karagiannis P, Selkirk C, Gould HJ, Jones P, Spicer JF, Karagiannis SN. Comparative reactivity of human IgE to cynomolgus monkey and human effector cells and effects on IgE effector cell potency. MAbs 2014; 6:509-22. [PMID: 24492303 DOI: 10.4161/mabs.27828] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Due to genetic similarities with humans, primates of the macaque genus such as the cynomolgus monkey are often chosen as models for toxicology studies of antibody therapies. IgE therapeutics in development depend upon engagement with the FcεRI and FcεRII receptors on immune effector cells for their function. Only limited knowledge of the primate IgE immune system is available to inform the choice of models for mechanistic and safety evaluations. METHODS The recognition of human IgE by peripheral blood lymphocytes from cynomolgus monkey and man was compared. We used effector cells from each species in ex vivo affinity, dose-response, antibody-receptor dissociation and potency assays. RESULTS We report cross-reactivity of human IgE Fc with cynomolgus monkey cells, and comparable binding kinetics to peripheral blood lymphocytes from both species. In competition and dissociation assays, however, human IgE dissociated faster from cynomolgus monkey compared with human effector cells. Differences in association and dissociation kinetics were reflected in effector cell potency assays of IgE-mediated target cell killing, with higher concentrations of human IgE needed to elicit effector response in the cynomolgus monkey system. Additionally, human IgE binding on immune effector cells yielded significantly different cytokine release profiles in each species. CONCLUSION These data suggest that human IgE binds with different characteristics to human and cynomolgus monkey IgE effector cells. This is likely to affect the potency of IgE effector functions in these two species, and so has relevance for the selection of biologically-relevant model systems when designing pre-clinical toxicology and functional studies.
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Affiliation(s)
- Louise Saul
- Cutaneous Medicine and Immunotherapy; St. John's Institute of Dermatology; Division of Genetics and Molecular Medicine & NIHR Biomedical Research Centre at Guy's and St. Thomas's Hospitals and King's College London; London, UK; Research Oncology, Division of Cancer Studies; King's College London; Guy's Hospital; Great Maze Pond; London, UK
| | - Debra H Josephs
- Cutaneous Medicine and Immunotherapy; St. John's Institute of Dermatology; Division of Genetics and Molecular Medicine & NIHR Biomedical Research Centre at Guy's and St. Thomas's Hospitals and King's College London; London, UK; Research Oncology, Division of Cancer Studies; King's College London; Guy's Hospital; Great Maze Pond; London, UK
| | - Keith Cutler
- Public Health England; Porton Down; Salisbury, Wiltshire UK
| | | | - Panagiotis Karagiannis
- Cutaneous Medicine and Immunotherapy; St. John's Institute of Dermatology; Division of Genetics and Molecular Medicine & NIHR Biomedical Research Centre at Guy's and St. Thomas's Hospitals and King's College London; London, UK
| | - Chris Selkirk
- Biotherapeutics Development Unit; Cancer Research UK; South Mimms, Hertfordshire UK
| | - Hannah J Gould
- Randall Division of Cell and Molecular Biophysics & Division of Asthma; Allergy and Lung Biology, MRC and Asthma UK Centre for Allergic Mechanisms of Asthma, King's College London; London, UK
| | - Paul Jones
- Drug Development Office; Strategy and Research Funding; Cancer Research UK; London, UK
| | - James F Spicer
- Research Oncology, Division of Cancer Studies; King's College London; Guy's Hospital; Great Maze Pond; London, UK
| | - Sophia N Karagiannis
- Cutaneous Medicine and Immunotherapy; St. John's Institute of Dermatology; Division of Genetics and Molecular Medicine & NIHR Biomedical Research Centre at Guy's and St. Thomas's Hospitals and King's College London; London, UK
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9
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Hunt J, Keeble AH, Dale RE, Corbett MK, Beavil RL, Levitt J, Swann MJ, Suhling K, Ameer-Beg S, Sutton BJ, Beavil AJ. A fluorescent biosensor reveals conformational changes in human immunoglobulin E Fc: implications for mechanisms of receptor binding, inhibition, and allergen recognition. J Biol Chem 2012; 287:17459-17470. [PMID: 22442150 PMCID: PMC3366799 DOI: 10.1074/jbc.m111.331967] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 03/08/2012] [Indexed: 11/06/2022] Open
Abstract
IgE binding to its high affinity receptor FcεRI on mast cells and basophils is a key step in the mechanism of allergic disease and a target for therapeutic intervention. Early indications that IgE adopts a bent structure in solution have been confirmed by recent x-ray crystallographic studies of IgEFc, which further showed that the bend, contrary to expectation, is enhanced in the crystal structure of the complex with receptor. To investigate the structure of IgEFc and its conformational changes that accompany receptor binding in solution, we created a Förster resonance energy transfer (FRET) biosensor using biologically encoded fluorescent proteins fused to the N- and C-terminal IgEFc domains (Cε2 and Cε4, respectively) together with the theoretical basis for quantitating its behavior. This revealed not only that the IgEFc exists in a bent conformation in solution but also that the bend is indeed enhanced upon FcεRI binding. No change in the degree of bending was seen upon binding to the B cell receptor for IgE, CD23 (FcεRII), but in contrast, binding of the anti-IgE therapeutic antibody omalizumab decreases the extent of the bend, implying a conformational change that opposes FcεRI engagement. HomoFRET measurements further revealed that the (Cε2)(2) and (Cε4)(2) domain pairs behave as rigid units flanking the conformational change in the Cε3 domains. Finally, modeling of the accessible conformations of the two Fab arms in FcεRI-bound IgE revealed a mutual exclusion not seen in IgG and Fab orientations relative to the membrane that may predispose receptor-bound IgE to cross-linking by allergens.
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Affiliation(s)
- James Hunt
- MRC and Asthma UK Centre in Allergic Mechanisms of Asthma, Guy's Hospital Campus, London SE1 1UL; The Randall Division of Cell and Molecular Biophysics, Guy's Hospital Campus, London SE1 1UL; The Division of Asthma Allergy and Lung Biology, King's College London, Guy's Hospital Campus, London SE1 1UL
| | - Anthony H Keeble
- MRC and Asthma UK Centre in Allergic Mechanisms of Asthma, Guy's Hospital Campus, London SE1 1UL; The Randall Division of Cell and Molecular Biophysics, Guy's Hospital Campus, London SE1 1UL; The Division of Asthma Allergy and Lung Biology, King's College London, Guy's Hospital Campus, London SE1 1UL
| | - Robert E Dale
- The Randall Division of Cell and Molecular Biophysics, Guy's Hospital Campus, London SE1 1UL
| | - Melissa K Corbett
- The Randall Division of Cell and Molecular Biophysics, Guy's Hospital Campus, London SE1 1UL
| | - Rebecca L Beavil
- MRC and Asthma UK Centre in Allergic Mechanisms of Asthma, Guy's Hospital Campus, London SE1 1UL; The Randall Division of Cell and Molecular Biophysics, Guy's Hospital Campus, London SE1 1UL; The Division of Asthma Allergy and Lung Biology, King's College London, Guy's Hospital Campus, London SE1 1UL
| | - James Levitt
- The Department of Physics, King's College London, Strand, London WC2R 2LS
| | - Marcus J Swann
- Farfield Group Limited, Voyager, Chicago Avenue, Manchester Airport, Manchester, M90 3DQ, United Kingdom
| | - Klaus Suhling
- The Department of Physics, King's College London, Strand, London WC2R 2LS
| | - Simon Ameer-Beg
- The Randall Division of Cell and Molecular Biophysics, Guy's Hospital Campus, London SE1 1UL
| | - Brian J Sutton
- MRC and Asthma UK Centre in Allergic Mechanisms of Asthma, Guy's Hospital Campus, London SE1 1UL; The Randall Division of Cell and Molecular Biophysics, Guy's Hospital Campus, London SE1 1UL
| | - Andrew J Beavil
- MRC and Asthma UK Centre in Allergic Mechanisms of Asthma, Guy's Hospital Campus, London SE1 1UL; The Randall Division of Cell and Molecular Biophysics, Guy's Hospital Campus, London SE1 1UL; The Division of Asthma Allergy and Lung Biology, King's College London, Guy's Hospital Campus, London SE1 1UL.
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10
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Abstract
Asthma is a chronic inflammatory disease of the airways. The causes of asthma and other inflammatory lung diseases are thought to be both environmental and heritable. Genetic studies do not adequately explain the heritability and susceptabilty to the disease, and recent evidence suggests that epigentic changes may underlie these processes. Epigenetics are heritable noncoding changes to DNA and can be influenced by environmental factors such as smoking and traffic pollution, which can cause genome-wide and gene-specific changes in DNA methylation. In addition, alterations in histone acetyltransferase/deacetylase activities can be observed in the cells of patients with lung diseases such as severe asthma and chronic obstructive pulmonary disease, and are often linked to smoking. Drugs such as glucocorticoids, which are used to control inflammation, are dependent on histone deacetylase activity, which may be important in patients with severe asthma and chronic obstructive pulmonary disease who do not respond well to glucocorticoid therapy. Future work targeting specific histone acetyltransferases/deacetylases or (de)methylases may prove to be effective future anti-inflammatory treatments for patients with treatment-unresponsive asthma.
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Affiliation(s)
- Andrew Durham
- Airways Disease Section, National Heart & Lung Institute, Imperial College, Dovehouse Street, London, SW3 6LY, UK.
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11
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Offermann DA, McKendrick JE, Sejberg JJP, Mo B, Holdom MD, Helm BA, Leatherbarrow RJ, Beavil AJ, Sutton BJ, Spivey AC. Synthesis and incorporation into cyclic peptides of tolan amino acids and their hydrogenated congeners: construction of an array of A-B-loop mimetics of the Cε3 domain of human IgE. J Org Chem 2012; 77:3197-214. [PMID: 22397517 DOI: 10.1021/jo202604q] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The disruption of the human immunolobulin E-high affinity receptor I (IgE-FcεRI) protein-protein interaction (PPI) is a validated strategy for the development of anti asthma therapeutics. Here, we describe the synthesis of an array of conformationally constrained cyclic peptides based on an epitope of the A-B loop within the Cε3 domain of IgE. The peptides contain various tolan (i.e., 1,2-biarylethyne) amino acids and their fully and partially hydrogenated congeners as conformational constraints. Modest antagonist activity (IC(50) ∼660 μM) is displayed by the peptide containing a 2,2'-tolan, which is the one predicted by molecular modeling to best mimic the conformation of the native A-B loop epitope in IgE.
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Affiliation(s)
- Daniel A Offermann
- Department of Chemistry, South Kensington Campus, Imperial College, London SW7 2AZ, UK
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12
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Holdom MD, Davies AM, Nettleship JE, Bagby SC, Dhaliwal B, Girardi E, Hunt J, Gould HJ, Beavil AJ, McDonnell JM, Owens RJ, Sutton BJ. Conformational changes in IgE contribute to its uniquely slow dissociation rate from receptor FcɛRI. Nat Struct Mol Biol 2011; 18:571-6. [PMID: 21516097 PMCID: PMC3357048 DOI: 10.1038/nsmb.2044] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 02/11/2011] [Indexed: 11/09/2022]
Abstract
Among antibody classes, IgE has a uniquely slow dissociation rate from, and high affinity for, its cell surface receptor FcɛRI. We show the structural basis for these key determinants of the ability of IgE to mediate allergic hypersensitivity through the 3.4-Å-resolution crystal structure of human IgE-Fc (consisting of the Cɛ2, Cɛ3 and Cɛ4 domains) bound to the extracellular domains of the FcɛRI α chain. Comparison with the structure of free IgE-Fc (reported here at a resolution of 1.9 Å) shows that the antibody, which has a compact, bent structure before receptor engagement, becomes even more acutely bent in the complex. Thermodynamic analysis indicates that the interaction is entropically driven, which explains how the noncontacting Cɛ2 domains, in place of the flexible hinge region of IgG antibodies, contribute together with the conformational changes to the unique binding properties of IgE.
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Affiliation(s)
- Mary D Holdom
- King's College London, Randall Division of Cell and Molecular Biophysics, London, UK
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13
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Sandomenico A, Monti SM, Palumbo R, Ruvo M. A new FcεRI receptor-mimetic peptide (PepE) that blocks IgE binding to its high affinity receptor and prevents mediator release from RBL 2H3 cells. J Pept Sci 2011; 17:604-9. [DOI: 10.1002/psc.1368] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 01/26/2011] [Accepted: 01/31/2011] [Indexed: 11/08/2022]
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14
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Abstract
Asthma is caused by both heritable and environmental factors. It has become clear that genetic studies do not adequately explain the heritability and susceptibility to asthma. The study of epigenetics, heritable non-coding changes to DNA may help to explain the heritable component of asthma. Additionally, epigenetic modifications can be influenced by the environment, including pollution and cigarette smoking, which are known asthma risk factors. These environmental trigger-induced epigenetic changes may be involved in skewing the immune system towards a Th2 phenotype following in utero exposure and thereby enhancing the risk of asthma. Alternatively, they may directly or indirectly modulate the immune and inflammatory processes in asthmatics via effects on treatment responsiveness. The study of epigenetics may therefore play an important role in our understanding and possible treatment of asthma and other allergic diseases. This article is part of a Special Issue entitled: Biochemistry of Asthma.
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Affiliation(s)
- Andrew L Durham
- National Heart and Lung Institute, Imperial College London, UK.
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15
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Wurzburg BA, Jardetzky TS. Conformational flexibility in immunoglobulin E-Fc 3-4 revealed in multiple crystal forms. J Mol Biol 2009; 393:176-90. [PMID: 19682998 PMCID: PMC2827403 DOI: 10.1016/j.jmb.2009.08.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2009] [Revised: 08/04/2009] [Accepted: 08/07/2009] [Indexed: 01/07/2023]
Abstract
The structure of immunoglobulin E (IgE)-Fc(3-4) has been solved in three new crystal forms, providing 13 snapshots of the Fc conformation and revealing a diverse range of open-closed motions among subunit chains and dimers. A more detailed analysis of the open-to-closed motion of IgE-Fc(3-4) was possible with so many structures, and the new structures allow a more thorough examination of the flexibility of IgE-Fc and its implications for receptor binding. The existence of a hydrophobic pocket at the elbow region of the Fc appears to be conformation dependent and suggests a means of regulating the IgE-Fc conformation (and potentially receptor binding) with small molecules.
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Affiliation(s)
- Beth A. Wurzburg
- Department of Structural Biology, Stanford University, Stanford CA 94305, USA
| | - Theodore S. Jardetzky
- Department of Structural Biology, Stanford University, Stanford CA 94305, USA,Corresponding author: ; phone: (650) 498-4179; fax: (650) 723-4943
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16
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Sandomenico A, Monti SM, Marasco D, Dathan N, Palumbo R, Saviano M, Ruvo M. IgE-binding properties and selectivity of peptide mimics of the FcvarepsilonRI binding site. Mol Immunol 2009; 46:3300-9. [PMID: 19699527 DOI: 10.1016/j.molimm.2009.07.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Accepted: 07/26/2009] [Indexed: 11/21/2022]
Abstract
FcvarepsilonRIalpha found on the surface of mast cells and basophiles mediates allergic diseases, anaphylaxis and asthma through binding of IgE. Disrupting this interaction with anti-IgE mAbs has proven an efficient approach to control these diseases. The crystallographic structure of the complex formed between the IgE-Fc and FcvarepsilonRIalpha extracellular domain has shown that recognition is mediated by residues in the second Ig-like domain of the receptor (D2) and in the loop connecting the D1 and D2 domains. In an attempt to obtain specific IgE antagonists, we have designed and prepared a polypeptide named IgE-Trap that partially reproduces the IgE receptor-binding sites and binds with micromolar affinity to soluble IgE. The polypeptide contains loops C'-E [residues 129-134] and F-G [residues 151-161] from the D2 domain joined by a linker, and loop B-C [residues 110-113]. Peptide binding to IgE has been assessed by SPR analyses and the data fit with a biphasic model of interaction, in agreement with the two-site mechanism reported for the native receptor. The polypeptide binds to immobilized IgE in a dose-dependent manner with a K(D) estimated to be around 6muM, while it does not recognize IgG nor IgA. Polypeptide sub-domains involved in IgE binding have also been defined, showing that loop C'-E connected to loop B-C, but also the isolated loop B-C alone suffice to bind immunoglobulins E with high selectively though with reduced affinity compared to IgE-Trap. ELISA and cytometric assays on RBL2H3 cells demonstrate that the interacting peptides are able to displace the binding of IgE to receptor, confirming affinity and specificity of these ligands and suggesting a potential application as modulators of disorders associated with inappropriate IgE production.
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17
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Karagiannis P, Singer J, Hunt J, Gan SKE, Rudman SM, Mechtcheriakova D, Knittelfelder R, Daniels TR, Hobson PS, Beavil AJ, Spicer J, Nestle FO, Penichet ML, Gould HJ, Jensen-Jarolim E, Karagiannis SN. Characterisation of an engineered trastuzumab IgE antibody and effector cell mechanisms targeting HER2/neu-positive tumour cells. Cancer Immunol Immunother 2009; 58:915-30. [PMID: 18941743 PMCID: PMC3017872 DOI: 10.1007/s00262-008-0607-1] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Accepted: 09/26/2008] [Indexed: 01/23/2023]
Abstract
Trastuzumab (Herceptin), a humanized IgG1 antibody raised against the human epidermal growth factor receptor 2 (HER2/neu), is the main antibody in clinical use against breast cancer. Pre-clinical evidence and clinical studies indicate that trastuzumab employs several anti-tumour mechanisms that most likely contribute to enhanced survival of patients with HER2/neu-positive breast carcinomas. New strategies are aimed at improving antibody-based therapeutics like trastuzumab, e.g. by enhancing antibody-mediated effector function mechanisms. Based on our previous findings that a chimaeric ovarian tumour antigen-specific IgE antibody showed greater efficacy in tumour cell killing, compared to the corresponding IgG1 antibody, we have produced an IgE homologue of trastuzumab. Trastuzumab IgE was engineered with the same light- and heavy-chain variable-regions as trastuzumab, but with an epsilon in place of the gamma-1 heavy-chain constant region. We describe the physical characterisation and ligand binding properties of the trastuzumab IgE and elucidate its potential anti-tumour activities in functional assays. Both trastuzumab and trastuzumab IgE can activate monocytic cells to kill tumour cells, but they operate by different mechanisms: trastuzumab functions in antibody-dependent cell-mediated phagocytosis (ADCP), whereas trastuzumab IgE functions in antibody-dependent cell-mediated cytotoxicity (ADCC). Trastuzumab IgE, incubated with mast cells and HER2/neu-expressing tumour cells, triggers mast cell degranulation, recruiting against cancer cells a potent immune response, characteristic of allergic reactions. Finally, in viability assays both antibodies mediate comparable levels of tumour cell growth arrest. These functional characteristics of trastuzumab IgE, some distinct from those of trastuzumab, indicate its potential to complement or improve upon the existing clinical benefits of trastuzumab.
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Affiliation(s)
- Panagiotis Karagiannis
- Cutaneous Medicine and Immunotherapy Unit, St. John's Institute of Dermatology, Division of Genetics and Molecular Medicine, King's College London School of Medicine, Guy's Tower, Guy's Hospital, London, UK
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18
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Jie HB, Yim D, Kim YB. Porcine Fc gammaRIII isoforms are generated by alternative splicing. Mol Immunol 2009; 46:1189-94. [PMID: 19124157 DOI: 10.1016/j.molimm.2008.11.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 11/09/2008] [Accepted: 11/12/2008] [Indexed: 11/30/2022]
Abstract
The Fc gammaRIII plays an essential role in antibody-mediating effector functions of immune cells. Here, we report that transcripts encoding porcine Fc gammaRIII isoforms are generated by alternative splicing. Fc gammaRIII a.1 is expressed on the cell surface while Fc gammaRIII a.2 is secreted from the transfected cells due to a partial deletion of the transmembrane domain. Interestingly, a putative soluble Fc gammaRIII (sCD16) is detected in circulating plasma. Both Fc gammaRIII a.2 and sCD16 exhibit a similar molecular mass (approximately 35 kDa) and contain the extracellular D2 domains that are structurally intact. Despite the D2 domain deletion, Fc gammaRIII a.3 associates with Fc gammaRIII a.1. Hence, these results suggest one possibility that three Fc gammaRIII isoforms differentially modulate Fc gammaRIII-mediated immune responses in the porcine system. Furthermore, we demonstrate that a cytolytic triggering G7 monoclonal antibody recognizes the D2 domain that is responsible for interacting with the immune complexes and subsequent activations of porcine innate immune cells. This result suggests that the D2 domain is a target region to develop therapeutic antibodies that regulate the FcR-mediated immune responses.
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Affiliation(s)
- Hyun-Bae Jie
- Asthma Research, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 49229-3039, USA
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19
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Taylor AI, Gould HJ, Sutton BJ, Calvert RA. Avian IgY Binds to a Monocyte Receptor with IgG-like Kinetics Despite an IgE-like Structure. J Biol Chem 2008; 283:16384-90. [DOI: 10.1074/jbc.m801321200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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20
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Karagiannis SN, Bracher MG, Beavil RL, Beavil AJ, Hunt J, McCloskey N, Thompson RG, East N, Burke F, Sutton BJ, Dombrowicz D, Balkwill FR, Gould HJ. Role of IgE receptors in IgE antibody-dependent cytotoxicity and phagocytosis of ovarian tumor cells by human monocytic cells. Cancer Immunol Immunother 2008; 57:247-63. [PMID: 17657488 PMCID: PMC11030264 DOI: 10.1007/s00262-007-0371-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Accepted: 07/07/2007] [Indexed: 11/29/2022]
Abstract
Antibodies directed against tumor-associated antigens are emerging as effective treatments for a number of cancers, although the mechanism(s) of action for some are unclear and still under investigation. We have previously examined a chimeric IgE antibody (MOv18 IgE), against the ovarian tumor-specific antigen, folate binding protein (FBP), and showed that it can direct human PBMC to kill ovarian cancer cells. We have developed a three-color flow cytometric assay to investigate the mechanism by which IgE receptors on U937 monocytes target and kill ovarian tumor cells. U937 monocytes express three IgE receptors, the high-affinity receptor, FcepsilonRI, the low-affinity receptor, CD23, and galectin-3, and mediate tumor cell killing in vitro by two mechanisms, cytotoxicity, and phagocytosis. Our results suggest that CD23 mediates phagocytosis, which is enhanced by upregulation of CD23 on U937 cells with IL-4, whereas FcepsilonRI mediates cytotoxicity. We show that effector : tumor cell bridging is associated with both activities. Galectin-3 does not appear to be involved in tumor cell killing. U937 cells and IgE exerted ovarian tumor cell killing in vivo in our xenograft model in nude mice. Harnessing IgE receptors to target tumor cells suggests the potential of tumor-specific IgE antibodies to activate effector cells in immunotherapy of ovarian cancer.
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Affiliation(s)
- Sophia N Karagiannis
- Randall Division of Cell and Molecular Biophysics, King's College London, Room 3.8, New Hunt's House, Guy's Campus, St Thomas's Street, London, SE1 1UL, UK.
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21
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Karagiannis SN, Bracher MG, Hunt J, McCloskey N, Beavil RL, Beavil AJ, Fear DJ, Thompson RG, East N, Burke F, Moore RJ, Dombrowicz DD, Balkwill FR, Gould HJ. IgE-antibody-dependent immunotherapy of solid tumors: cytotoxic and phagocytic mechanisms of eradication of ovarian cancer cells. J Immunol 2007; 179:2832-43. [PMID: 17709497 DOI: 10.4049/jimmunol.179.5.2832] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Abs have a paramount place in the treatment of certain, mainly lymphoid, malignancies, although tumors of nonhemopoietic origin have proved more refractory ones. We have previously shown that the efficacy of immunotherapy of solid tumors, in particular ovarian carcinoma, may be improved by the use of IgE Abs in place of the conventional IgG. An IgE Ab (MOv18 IgE) against an ovarian-tumor-specific Ag (folate binding protein), in combination with human PBMC, introduced into ovarian cancer xenograft-bearing mice, greatly exceeded the analogous IgG1 in promoting survival. In this study, we analyzed the mechanisms by which MOv18 IgE may exert its antitumor activities. Monocytes were essential IgE receptor-expressing effector cells that mediated the enhanced survival of tumor-bearing mice by MOv18 IgE and human PBMC. Monocytes mediated MOv18 IgE-dependent ovarian tumor cell killing in vitro by two distinct pathways, cytotoxicity and phagocytosis, acting respectively through the IgE receptors FcepsilonRI and CD23. We also show that human eosinophils were potent effector cells in MOv18 IgE Ab-dependent ovarian tumor cell cytotoxicity in vitro. These results demonstrate that IgE Abs can engage cell surface IgE receptors and activate effector cells against ovarian tumor cells. Our findings offer a framework for an improved immunotherapeutic strategy for combating solid tumors.
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Affiliation(s)
- Sophia N Karagiannis
- Randall Division of Cell and Molecular Biophysics, New Hunt's House, King's College London, Guy's Campus, London, United Kingdom.
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22
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Abstract
Discovery of a large family of Fc receptor-like (FCRL) molecules, homologous to the well-known receptors for the Fc portion of immunoglobulin (FCR), has uncovered an impressive abundance of immunoglobulin superfamily (IgSF) genes in the human 1q21-23 chromosomal region and revealed significant diversity for these genes between humans and mice. The observation that FCRL representatives are members of an ancient multigene family that share a common ancestor with the classical FCR is underscored by their linked genomic locations, gene structure, shared extracellular domain composition, and utilization of common cytoplasmic tyrosine-based signaling elements. In contrast to the conventional FCR, however, FCRL molecules possess diverse extracellular frameworks, autonomous or dual signaling properties, and preferential B lineage expression. Most importantly, there is no strong evidence thus far to support a role for them as Ig-binding receptors. These characteristics, in addition to their identification in malignancies and autoimmune disorders, predict a fundamental role for these receptors as immunomodulatory agents in normal and subverted B lineage cells.
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Affiliation(s)
- Randall S Davis
- Division of Developmental and Clinical Immunology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294-3300, USA.
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23
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Harwood NE, Price NC, McDonnell JM. Catalytic folding of the Cε3 domain by its high affinity receptor. FEBS Lett 2006; 580:2129-34. [PMID: 16563391 DOI: 10.1016/j.febslet.2006.03.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Revised: 03/01/2006] [Accepted: 03/01/2006] [Indexed: 11/30/2022]
Abstract
The interaction of immunoglobulin E (IgE) with its cellular receptor FcepsilonRIalpha is a central regulator of allergy. Structural studies have identified the third domain (Cepsilon3) of the constant region of epsilon heavy chain as the receptor binding region. The isolated Cepsilon3 domain is a "molten globule" that becomes structured upon binding of the FcepsilonRIalpha ligand. In this study, fluorescence and nuclear magnetic resonance spectroscopies are used to characterise the role of soluble FcepsilonRIalpha in the folding of the monomeric Cepsilon3 domain of IgE. Soluble FcepsilonRIalpha is shown to display characteristic properties of a catalyst for the folding of Cepsilon3, with the rate of Cepsilon3 folding being dependent on the concentration of the receptor.
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Affiliation(s)
- Naomi E Harwood
- Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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24
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Hunt J, Beavil RL, Calvert RA, Gould HJ, Sutton BJ, Beavil AJ. Disulfide linkage controls the affinity and stoichiometry of IgE Fcepsilon3-4 binding to FcepsilonRI. J Biol Chem 2005; 280:16808-14. [PMID: 15743766 DOI: 10.1074/jbc.m500965200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
IgE antibodies cause long-term sensitization of tissue mast cells and blood basophils toward allergen-induced cross-linking and triggering of allergic inflammation. This persistence of IgE binding is due to its uniquely high affinity for the receptor FcepsilonRI and in particular its slow rate of dissociation once bound. The binding interface consists of two subsites, one contributed by each Cepsilon3 domain of IgE Fc in a 1:1 complex. We have investigated the contributions of Cepsilon3 disulfide linkage and glycosylation to the kinetics and affinity of binding of an Fc subfragment (Fcepsilon3-4) to a soluble receptor fragment (sFcepsilonRIalpha). In contrast to IgG Fc where deglycosylation abrogates receptor binding activity, the removal of the N-linked carbohydrate at Asn-394 in Fcepsilon3-4 only reduces binding affinity by a factor of 4, principally because of a faster off-rate. Removal of the inter-heavy chain disulfide bond unexpectedly resulted in a fragment with a much faster off-rate and the potential to form a complex with a 2:1 stoichiometry (sFcepsilonRIalpha:Fcepsilon3-4). This permitted the determination of the affinity of a single, natively folded Cepsilon3 domain for the first time. The low affinity Ka approximately 10(5)-10(6) m-1, similar to that determined previously for an isolated and partially folded Cepsilon3 domain, demonstrates that substantial reduction in affinity can be achieved by preventing the engagement of one of the two Cepsilon3 domains. Recent structural data indicate that conformational change in IgE is required to allow both Cepsilon3 domains to bind, and thus an allosteric inhibitor that prevents access to the second Cepsilon3 has the potential to reduce the ability of IgE to sensitize allergic effector cells.
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Affiliation(s)
- James Hunt
- Randall Division of Cell and Molecular Biophysics and the Division of Asthma, Allergy and Lung Biology, King's College London, Guy's Campus, London SE1 1UL, United Kingdom
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25
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Abstract
The interaction between IgE and its high affinity receptor (FcepsilonRI) is a critical step in the development of allergic responses. Detailed characterization of the IgE-FcepsilonRI interaction may offer insights into possible modes of inhibiting the interaction, which could thereby act as a potential therapy for allergy. In this study, NMR, CD, and fluorescence spectroscopies have been used to characterize structurally the Cepsilon3 domain of IgE and its interaction with other protein ligands, namely, Cepsilon2, Cepsilon4, sFcepsilonRIalpha, and CD23. We have shown that the recombinant Cepsilon3 domain exists alone in solution as a "molten globule." On interaction with sFcepsilonRIalpha, Cepsilon3 adopts a folded tertiary structure, as shown by the release of the fluorescent probe 8-anilinonaphthalene-1-sulfonate and by characteristic changes in the (1)H, (15)N heteronuclear single quantum coherence NMR spectrum. However, the interactions between the Cepsilon3 domain and Cepsilon2, Cepsilon4, or CD23 do not induce such folding and would therefore be expected to involve only local interaction surfaces. The conformational flexibility of the Cepsilon3 domain of the whole IgE molecule may play a role in allowing fine tuning of the affinity and specificity of IgE for a variety of different physiological ligands and may be involved in the conformational change of IgE postulated to occur on interaction with FcepsilonRI.
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Affiliation(s)
- Naomi E Price
- Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
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26
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Abstract
Allergic individuals exposed to minute quantities of allergen experience an immediate response. Immediate hypersensitivity reflects the permanent sensitization of mucosal mast cells by allergen-specific IgE antibodies bound to their high-affinity receptors (FcepsilonRI). A combination of factors contributes to such long-lasting sensitization of the mast cells. They include the homing of mast cells to mucosal tissues, the local synthesis of IgE, the induction of FcepsilonRI expression on mast cells by IgE, the consequent downregulation of FcgammaR (through an insufficiency of the common gamma-chains), and the exceptionally slow dissociation of IgE from FcepsilonRI. To understand the mechanism of the immediate hypersensitivity phenomenon, we need explanations of why IgE antibodies are synthesized in preference to IgG in mucosal tissues and why the IgE is so tenaciously retained on mast cell-surface receptors. There is now compelling evidence that the microenvironment of mucosal tissues of allergic disease favors class switching to IgE; and the exceptionally high affinity of IgE for FcepsilonRI can now be interpreted in terms of the recently determined crystal structures of IgE-FcepsilonRI and IgG-FcgammaR complexes. The rate of local IgE synthesis can easily compensate for the rate of the antibody dissociation from its receptors on mucosal mast cells. Effective mechanisms ensure that allergic reactions are confined to mucosal tissues, thereby minimizing the risk of systemic anaphylaxis.
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MESH Headings
- Allergens
- Amino Acid Sequence
- Animals
- Antigen-Presenting Cells/immunology
- B-Lymphocytes/immunology
- Blood Platelets/immunology
- Crystallography, X-Ray
- Disease Models, Animal
- Eosinophils/immunology
- Humans
- Hypersensitivity/etiology
- Hypersensitivity/immunology
- Immunoglobulin Class Switching
- Immunoglobulin E/chemistry
- Immunoglobulin E/genetics
- Immunoglobulin E/metabolism
- Models, Molecular
- Monocytes/immunology
- Nuclear Magnetic Resonance, Biomolecular
- Receptors, IgE/chemistry
- Receptors, IgE/genetics
- Receptors, IgE/metabolism
- Receptors, IgG/chemistry
- Receptors, IgG/metabolism
- Schistosomiasis/immunology
- T-Lymphocytes, Helper-Inducer/immunology
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Affiliation(s)
- Hannah J Gould
- The Randall Centre, King's College London, United Kingdom.
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27
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Abstract
The last decade has seen a wealth of studies aimed at the characterization of the binding between IgE and its high-affinity receptor, FcepsilonRI. IgE-FcepsilonRI complex formation is a major molecular event in atopic allergy. IgE-FcepsilonRI binding connects allergen recognition to cellular triggering, ultimately leading to disease manifestations. Consequently, pharmacological intervention at this site is of universal relevance for atopic allergy. Until recent years, the complexity of IgE-FcepsilonRI binding, together with the difficulty in obtaining fully functional recombinant IgE and FcepsilonRI derivatives, often led to confusion and difficulty in data interpretation. Major advances in the understanding of this intricate protein-protein interaction have now been accomplished. Most of the current knowledge on the IgE-FcepsilonRI recognition mode derives from long-lasting efforts in the field of structural biology. Protein engineering, high-throughput screening, immunological and biochemical studies also made relevant contributions in this domain. The data accumulated to date predict that IgE and FcepsilonRI use their modular architecture to approach each other in an asymmetric stepwise manner determining a 1:1 stoichiometry. This recognition appears to be enhanced by conformational changes occurring upon binding, leading to the well-known high-affinity. In conclusion, the vast amount of high-quality data available broadened our knowledge on the IgE-FcepsilonRI system; however, the fine structural details of the recognition process are still largely hypothetical. More studies are necessary to provide the experimental comprehensive picture required to carefully design efficient drugs acting at the IgE-FcepsilonRI interface.
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Affiliation(s)
- Luca Vangelista
- Department of Biology and Genetics, University of Milan, Milan, Italy.
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28
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Chen BH, Kilmon MA, Ma C, Caven TH, Chan-Li Y, Shelburne AE, Tombes RM, Roush E, Conrad DH. Temperature effect on IgE binding to CD23 versus Fc epsilon RI. J Immunol 2003; 170:1839-45. [PMID: 12574349 DOI: 10.4049/jimmunol.170.4.1839] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A chimeric soluble CD23, consisting of the extracellular domain of mouse CD23 and a modified leucine zipper (lz-CD23), has been shown to inhibit IgE binding to the FcepsilonRI. A similar human CD23 construct was also shown to inhibit binding of human IgE to human FcepsilonRI. In both systems, the inhibition was found to be temperature dependent; a 10-fold molar excess of lz-CD23 gave 90-98% inhibition at 4 degrees C, dropping to 20-30% inhibition at 37 degrees C. Surface plasmon resonance analysis of lz-CD23 binding to an IgE-coated sensor chip suggested that the effective concentration of lz-CD23 was lower at the higher temperatures. Analysis of (125)I-IgE binding to CD23(+)-Chinese hamster ovary cells also indicated that increased temperature resulted in a lower percentage of IgE capable of interacting with CD23. In contrast, IgE interacts more effectively with FcepsilonRI(+)-rat basophilic leukemia cells at 37 degrees C compared with 4 degrees C. The results support the concept that the open and closed IgE structures found by crystallography interact differently with the two IgE receptors and suggest that temperature influences the relative percentage of IgE in the respective structural forms. Changes in CD23 oligomerization also plays a role in the decreased binding seen at physiological temperatures.
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Affiliation(s)
- Bing-Hung Chen
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA 23298, USA
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29
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Abstract
The high affinity receptor for IgE, FcERI, is at the core of the allergic reaction. This receptor is expressed mainly on mast cells and basophils. Interaction of an allergen with its specific IgE bound to FcERI triggers cell activation, which induces the release of numerous mediators that are responsible for allergic manifestations. The recent increase in the prevalence of allergic diseases in developed countries has resulted in renewed efforts towards the development of new drugs. One of these is a humanised antibody directed against the IgE ligand. This antibody recognises specifically free but not FcERI-bound IgE thus preventing ligand binding and subsequent cell activation. This antibody has shown some efficacy in clinical trials involving patients with asthma and allergic rhinitis. The recent elucidation of the tridimensional structure of the complex between IgE and FcERI provides unexpected information regarding the mechanism of assembly of the complex, which now can be used to design small chemical compounds capable of specifically inhibiting this interaction.
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Affiliation(s)
- Ulrich Blank
- Institut Pasteur, Unité d'Immuno-Allergie, 25, rue du Docteur Roux, 75724 Paris, France.
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30
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Abstract
Previously, a soluble mouse CD23 chimera, composed of an N-terminal trimeric isoleucine zipper motif (lz) followed by the entire extracellular region (amino acids 48-331) of CD23 (lz-CD2348-331), was prepared and exhibited strong binding to rodent immunoglobulin E (IgE). In the current study, we report the construction of a similar human chimeric protein (lz-huCD2345-321), as well as a series of murine chimeric lz-CD23 mutants with incremental portions of stalk deleted, to further investigate the role of the stalk region in mediating the CD23-IgE interaction. All chimeric proteins were designed such that the predicted heptad structure of the stalk was retained. IgE binding, as determined by the capacity to inhibit 125I-IgE from binding to FcepsilonRI-bearing RBL-2H3 cells, and by surface plasmon-resonance analysis using an IgE-coated sensor chip, was unchanged from the original lz chimera and the binding parameters were similar to those of cell-surface CD23. The minimal murine chimera that retained IgE-binding activity was lz-CD23139-331, which still contains 35 amino acids of the stalk region. When the lz motif was linked to CD23 amino acid 157 (or higher), significant IgE-binding capacity was lost. With human lz-CD23, as with mouse, deletion of the stalk greatly reduced IgE-binding ability. In summary, the data support the concept that at least a portion of the stalk region of CD23 plays a crucial role in maintaining high-affinity/avidity interaction with IgE. The lz-CD23 constructs represent a possible alternative for both blocking the IgE/FcepsilonRI interaction and inhibiting IgE production by B lymphocytes.
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Affiliation(s)
- Bing-Hung Chen
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA 23298, USA
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31
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Wan T, Beavil RL, Fabiane SM, Beavil AJ, Sohi MK, Keown M, Young RJ, Henry AJ, Owens RJ, Gould HJ, Sutton BJ. The crystal structure of IgE Fc reveals an asymmetrically bent conformation. Nat Immunol 2002; 3:681-6. [PMID: 12068291 DOI: 10.1038/ni811] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The distinguishing structural feature of immunoglobulin E (IgE), the antibody responsible for allergic hypersensitivity, is the C epsilon 2 domain pair that replaces the hinge region of IgG. The crystal structure of the IgE Fc (constant fragment) at a 2.6-A resolution has revealed these domains. They display a distinctive, disulfide-linked Ig domain interface and are folded back asymmetrically onto the C epsilon 3 and C epsilon 4 domains, which causes an acute bend in the IgE molecule. The structure implies that a substantial conformational change involving C epsilon 2 must accompany binding to the mast cell receptor Fc epsilon RI. This may be the basis of the exceptionally slow dissociation rate of the IgE-Fc epsilon RI complex and, thus, of the ability of IgE to cause persistent allergic sensitization of mast cells.
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Affiliation(s)
- Tommy Wan
- The Randall Centre, King's College London, New Hunt's House, London SE1 1UL, UK
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32
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Abstract
Fc receptors mediate antibody dependent inflammatory response and cytotoxicity as well as certain autoimmune dysfunctions. Fcgamma receptors interact with IgG antibodies by binding the Fc portion of the antibody in asymmetric fashion creating a 1:1 receptor-ligand stoichiometry. Regions of the C-terminal domain of Fc receptors including the BC, C'E, FG loops, and the C' beta-strand interact with immunoglobulins. The lower hinge region of the antibody contributes most of the binding to the low affinity Fcgamma receptors. Carbohydrates attached to the conserved glycosylation site on Fc portion of an antibody are critical to the recognition of immunoglobulins by the low affinity Fcgamma receptor. They are likely to function as a substitution for the hydrophobic core to preserve an optimal lower hinge conformation for the receptor binding. Subtype specificities of FcgammaRIII receptor probably are determined by the length of the lower hinge regions of immunoglobulins, but not their amino acid composition as revealed by the binding study of the lower hinge peptides. These studies also paved a new way for designing of novel therapeutic compounds in fighting autoimmune diseases.
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Affiliation(s)
- Sergei Radaev
- Structural Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12441 Parklawn Drive, Rockville, MD 20852, USA
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33
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Abstract
The interaction of IgE antibodies with the high affinity IgE receptor, FcepsilonRI, is a key step in the initiation of anti-parasitic immunity and allergic reactions. Recent structural studies of the receptor, the IgE-Fc and the IgE-Fc:FcepsilonRI complex have revealed how these two proteins interact to prime mast cell responses to antigen. The structures have revealed a novel arrangement for the FcepsilonRI ectodomains that is also observed in homologous members of this antibody receptor family. The crystal structure of the IgE-Fc:FcepsilonRI complex clarified how a 1:1 complex between the antibody and receptor is formed, with the receptor binding each chain of the antibody Fc dimer. The IgE-Fc structure in the absence of the receptor revealed the potential for large conformational rearrangements within the IgE that may affect receptor binding. These studies provide the basis for further investigation of the specificity of antibody:receptor binding and for the development of new treatments for allergic hypersensitivities.
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Affiliation(s)
- Beth A Wurzburg
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60208-3500, USA
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34
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Iwasaki A, Doi T, Umetani M, Watanabe M, Suda M, Hattori Y, Nagoya T. Affinity improvement of the high-affinity immunoglobulin E receptor by phage display. Biochem Biophys Res Commun 2002; 293:542-8. [PMID: 12054635 DOI: 10.1016/s0006-291x(02)00261-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The immunoglobulin E (IgE)-binding site of its high-affinity receptor is localized in the second immunoglobulin-like domain (D2) of the alpha-subunit (Fc epsilon RI alpha). In this study, the randomized pentapeptides were introduced between Glu(132) and Ile(138) of Fc epsilon RI alpha D2 and displayed on a filamentous phage. After eight rounds of panning, a phage clone having a mutation of Asp(135)Tyr(136)Met(137) in Fc epsilon RI alpha D2 was obtained. The binding affinity of the mutant phages to immobilized IgE was approximately 500 times higher than that of the wild type. The mutant phages competitively inhibited the binding of IgE to the soluble receptor at a 50% inhibition (IC(50)) value of 116 pM. The mutant Fc epsilon RI alpha D2, which had been expressed as a fusion protein with glutathione S-transferase in Escherichia coli, also showed higher IgE-binding capacity than the wild type. The mutant Fc epsilon RI alpha D2 is expected to manifest its improved IgE-binding affinity together with any fusion partner.
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Affiliation(s)
- Akio Iwasaki
- Institute of Applied Biochemistry, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
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35
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Mackay GA, Hulett MD, Cook JPD, Trist HM, Henry AJ, McDonnell JM, Beavil AJ, Beavil RL, Sutton BJ, Hogarth PM, Gould HJ. Mutagenesis within human FcepsilonRIalpha differentially affects human and murine IgE binding. J Immunol 2002; 168:1787-95. [PMID: 11823511 DOI: 10.4049/jimmunol.168.4.1787] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Soluble fragments of the alpha-chain of FcepsilonRI, the high-affinity receptor for IgE, compete with membrane-bound receptors for IgE and may thus provide a means to combat allergic responses. Mutagenesis within FcepsilonRIalpha is used in this study, in conjunction with the crystal structure of the FcepsilonRIalpha/IgE complex, to define the relative importance of specific residues within human FcepsilonRIalpha for IgE binding. We have also compared the effects of these mutants on binding to both human and mouse IgE, with a view to evaluating the mouse as an appropriate model for the analysis of future agents designed to mimic the human FcepsilonRIalpha and attenuate allergic disease. Three residues within the C-C' region of the FcepsilonRIalpha2 domain and two residues within the alpha2 proximal loops of the alpha1 domain were selected for mutagenesis and tested in binding assays with human and mouse IgE. All three alpha2 mutations (K117D, W130A, and Y131A) reduced the affinity of human IgE binding to different extents, but K117D had a far more pronounced effect on mouse IgE binding, and although Y131A had little effect, W130A modestly enhanced binding to mouse IgE. The mutations in alpha1 (R15A and F17A) diminished binding to both human and mouse IgE, with these effects most likely caused by disruption of the alpha1/alpha2 interface. Our results demonstrate that the effects of mutations in human FcepsilonRIalpha on mouse IgE binding, and hence the inhibitory properties of human receptor-based peptides assayed in rodent models of allergy, may not necessarily reflect their activity in a human IgE-based system.
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Affiliation(s)
- Graham A Mackay
- Randall Centre, New Hunt's House, King's College London, Guy's Campus, London, United Kingdom
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36
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Abstract
With the introduction of new instruments and improved sensor chip chemistries, surface plasmon resonance (SPR) is finding new applications for molecular interaction studies. Easy access to high-quality kinetic and thermodynamic data for macromolecular binding events is providing insights into the fundamental mechanisms of molecular recognition. Progress is being made to allow larger-scale interaction studies. In addition, combining SPR with other analytical methods is enabling SPR-based analysis of interaction proteomics.
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Affiliation(s)
- J M McDonnell
- The Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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37
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Abstract
We have solved the structure of the human high affinity IgE receptor, Fc epsilon RI alpha, in six different crystal forms, showing the structure in 15 different chemical environments. This database of structures shows no change in the overall shape of the molecule, as the angle between domains 1 and 2 (D1 and D2) varies little across the ensemble. However, the receptor has local conformational variability in the C' strand of D2 and in the BC loop of D1. In every crystal form, a residue inserts between tryptophan residues 87 and 110, mimicking the position of a proline from the IgE ligand. The different crystal forms reveal a distribution of carbohydrates lining the front and back surfaces of the structure. An analysis of crystal contacts in the different forms indicates regions where the molecule interacts with other proteins, and reveals a potential new binding site distal to the IgE binding site. The results of this study point to new directions for the design of molecules to inhibit the interaction of Fc epsilon RI alpha with its natural ligand and thus to prevent a primary step in the allergic response.
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Affiliation(s)
- S C Garman
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Twinbrook II, 12441 Parklawn Drive, Rockville, MD 20852, USA.
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38
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Abstract
Fc gamma Receptors (Fc gamma R) are membrane glycoproteins that bind the Fc portion of immunoglobulin G (IgG). The cross linking of Fc gamma R-bound IgG by multivalent antigens allows clustering of the Fc gamma R and initiates a variety of effector mechanisms which play a key role in immune defenses against pathogens. The Fc region is composed of two identical polypeptide chains, which are related to each other by a two-fold axis. Recent elucidation of the crystal structure of human Fc gamma RII provided two distinct views of modes of IgG-Fc gamma R interactions, which is controversial against each other. Nuclear magnetic resonance (NMR) spectroscopy provides a unique and irreplaceable tool to solve these issues. We recently studied the interaction between the Fc fragment of mouse IgG2b and the extracellular domain of mouse Fc gamma RII by this method. We showed that Fc gamma RII binds to a negatively charged area of the CH2 domain, corresponding to the lower hinge region, and that the binding of Fc gamma RII onto one of the two symmetrically related sites on the Fc induces a conformational change in the other site. This conformational change may account for the 1:1 stoichiometry that we and others observed between Fc gamma R and Fc. We therefore propose a model that explains why the interaction between IgG molecules and Fc gamma R does not trigger cellular responses in the absence of cross linking by multivalent antigens and does not lead to spontaneous inflammatory responses that would be deleterious for the organism.
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Affiliation(s)
- K Kato
- Faculty of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
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39
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Abstract
Fcgamma receptors mediate antibody-dependent inflammatory responses and cytotoxicity as well as certain autoimmune dysfunctions. Here we report the crystal structure of a human Fc receptor (FcgammaRIIIB) in complex with an Fc fragment of human IgG1 determined from orthorhombic and hexagonal crystal forms at 3.0- and 3.5-A resolution, respectively. The refined structures from the two crystal forms are nearly identical with no significant discrepancies between the coordinates. Regions of the C-terminal domain of FcgammaRIII, including the BC, C'E, FG loops, and the C' beta-strand, bind asymmetrically to the lower hinge region, residues Leu(234)-Pro(238), of both Fc chains creating a 1:1 receptor-ligand stoichiometry. Minor conformational changes are observed in both the receptor and Fc upon complex formation. Hydrophobic residues, hydrogen bonds, and salt bridges are distributed throughout the receptor.Fc interface. Sequence comparisons of the receptor-ligand interface residues suggest a conserved binding mode common to all members of immunoglobulin-like Fc receptors. Structural comparison between FcgammaRIII.Fc and FcepsilonRI.Fc complexes highlights the differences in ligand recognition between the high and low affinity receptors. Although not in direct contact with the receptor, the carbohydrate attached to the conserved glycosylation residue Asn(297) on Fc may stabilize the conformation of the receptor-binding epitope on Fc. An antibody-FcgammaRIII model suggests two possible ligand-induced receptor aggregations.
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Affiliation(s)
- S Radaev
- Structural Biology Section, Laboratory of Immunogenetics, NIAID, National Institutes of Health, Rockville, Maryland 20852, USA
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40
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Metzler DE, Metzler CM, Sauke DJ. Biochemical Defense Mechanisms. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50034-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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41
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Abstract
Fc receptors play a major role in immune defenses against pathogens and in inflammatory processes. The crystal structure of a human immunoglobulin receptor, FcgammaRIIIb, has been determined to 1.8 A resolution. The overall fold consists of two immunoglobulin-like domains with an acute interdomain hinge angle of approximately 50 degrees. Trp-113, wedged between the N-terminal D1 and the C-terminal D2 domains, appears to further restrict the hinge angle. The putative Fc binding region of the receptor carries a net positive charge complementary to the negative-charged receptor binding regions on Fc. A 1:1 binding stoichiometry between the receptor and Fc was measured by both the equilibrium and nonequilibrium size-exclusion chromatography. Two separate parallel dimers are observed in the crystal lattice, offering intriguing models for receptor aggregation.
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Affiliation(s)
- Y Zhang
- Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston 77555, USA
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42
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Garman SC, Wurzburg BA, Tarchevskaya SS, Kinet JP, Jardetzky TS. Structure of the Fc fragment of human IgE bound to its high-affinity receptor Fc epsilonRI alpha. Nature 2000; 406:259-66. [PMID: 10917520 DOI: 10.1038/35018500] [Citation(s) in RCA: 256] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The initiation of immunoglobulin-E (IgE)-mediated allergic responses requires the binding of IgE antibody to its high-affinity receptor, Fc epsilonRI. Crosslinking of Fc epsilonRI initiates an intracellular signal transduction cascade that triggers the release of mediators of the allergic response. The interaction of the crystallizable fragment (Fc) of IgE (IgE-Fc) with Fc epsilonRI is a key recognition event of this process and involves the extracellular domains of the Fc epsilonRI alpha-chain. To understand the structural basis for this interaction, we have solved the crystal structure of the human IgE-Fc-Fc epsilonRI alpha complex to 3.5-A resolution. The crystal structure reveals that one receptor binds one dimeric IgE-Fc molecule asymmetrically through interactions at two sites, each involving one C epsilon3 domain of the IgE-Fc. The interaction of one receptor with the IgE-Fc blocks the binding of a second receptor, and features of this interaction are conserved in other members of the Fc receptor family. The structure suggests new approaches to inhibiting the binding of IgE to Fc epsilonRI for the treatment of allergy and asthma.
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Affiliation(s)
- S C Garman
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208, USA
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43
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Abstract
The immune response depends on the binding of opsonized antigens to cellular Fc receptors and the subsequent initiation of various cellular effector functions of the immune system. Here we describe the crystal structures of a soluble Fc gamma receptor (sFc gammaRIII, CD16), an Fc fragment from human IgG1 (hFc1) and their complex. In the 1:1 complex the receptor binds to the two halves of the Fc fragment in contact with residues of the C gamma2 domains and the hinge region. Upon complex formation the angle between the two sFc gammaRIII domains increases significantly and the Fc fragment opens asymmetrically. The high degree of amino acid conservation between sFc gammaRIII and other Fc receptors, and similarly between hFc1 and related immunoglobulins, suggest similar structures and modes of association. Thus the described structure is a model for immune complex recognition and helps to explain the vastly differing affinities of other Fc gammaR-IgG complexes and the Fc epsilonRI alpha-IgE complex.
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Affiliation(s)
- P Sondermann
- Max-Planck-Institut für Biochemie, Martinsried, Germany.
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Rudolf MP, Zuercher AW, Nechansky A, Ruf C, Vogel M, Miescher SM, Stadler BM, Kricek F. Molecular basis for nonanaphylactogenicity of a monoclonal anti-IgE antibody. J Immunol 2000; 165:813-9. [PMID: 10878355 DOI: 10.4049/jimmunol.165.2.813] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
IgE Abs mediate allergic responses by binding to specific high affinity receptors (FcepsilonRI) on mast cells and basophils. Therefore, the IgE/FcepsilonRI interaction is a target for clinical intervention in allergic disease. An anti-IgE mAb, termed BSW17, is nonanaphylactogenic, although recognizing IgE bound to FcepsilonRI, and interferes with binding of IgE to FcepsilonRI. Thus, BSW17 represents a candidate Ab for treatment of IgE-mediated disorders. By panning BSW17 against random peptide libraries displayed on phages, we defined mimotopes that mimic the conformational epitope recognized on human IgE. Two types of mimotopes, one within the Cepsilon3 and one within the Cepsilon4 domain, were identified, indicating that this mAb may recognize either a large conformational epitope or eventually two distinct epitopes on IgE. On the basis of alignments of the two mimotopes with the human IgE sequence, we postulate that binding of BSW17 to the Cepsilon3 region predominantly blocks binding of IgE to FcepsilonRI, leading to neutralization of IgE. Moreover, binding of BSW17 to the Cepsilon4 region may explain how BSW17 recognizes FcepsilonRI-bound IgE, and binding to this region may also interfere with degranulation of IgE sensitized cells (basophils and mast cells). As a practical application of these findings, mimotope peptides coupled to a carrier protein may be used for the development of a peptide-based anti-allergy vaccine by induction of anti-IgE Abs similar to the current approach of using humanized nonanaphylactogenic anti-IgE Abs as a passive vaccine.
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Affiliation(s)
- M P Rudolf
- Institute of Immunology and Allergology, Inselspital, University of Bern, Bern, Switzerland
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45
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Yanagida M, Irikura M, Suto H, Yagi S, Ogawa H, Ra C. Kinetic analysis of the interaction between recombinant human Fc(epsilon)RIalpha and serum IgEs from allergic patients. Clin Immunol 2000; 95:190-6. [PMID: 10866125 DOI: 10.1006/clim.2000.4868] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Binding of IgE to the high-affinity IgE receptor (Fc(epsilon)RI) is the essential event for allergic reaction. Although there are many reports on binding kinetics between myeloma IgE and Fc(epsilon)RI, little is known about the kinetics between heterogeneous polyclonal IgE in the serum and Fc(epsilon)RIalpha. To elucidate the binding characteristics of heterogeneous serum IgE, we measured kinetic parameters of binding between IgE from allergic patients and a recombinant ectodomain of the human Fc(epsilon)RIalpha subunit by real-time interaction analysis based on surface plasmon resonance. Purified IgE monomer from the plasma of allergic patients displayed kinetics for the interaction with Fc(epsilon)RIalpha similar to those of myeloma IgE. In the case of crude IgE samples from allergic patients, one of seven specimens showed significantly higher affinity than highly purified IgE, suggesting that it is possible for IgEs in this specimen to form complexes of higher molecular weight.
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Affiliation(s)
- M Yanagida
- Corporate Research and Development Laboratory, Tonen Corporation, Iruma-gun, Saitama, Japan
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46
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Abstract
Genetics studies have identified the gene for the high-affinity IgE receptor (FC(epsilon)RI) beta subunit as a candidate gene for atopy. We have shown that beta is an intrinsic signaling amplifier leading to enhanced allergic responses in vivo. Here we report that beta has a second amplification function: the amplification of Fc(epsilon)RI cell surface expression. This function is due to an early association of beta with alpha, resulting in improved trafficking and maturation of alpha and receptor complexes. These data provide a possible molecular explanation for the large difference in Fc(epsilon)RI density between beta-cells such as monocytes, dendritic cells, and beta+ effector cells (mast cells, basophils). In beta+ cells, the combined signaling and expression amplification results in an estimated 12- to 30-fold amplification of downstream events.
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Affiliation(s)
- E Donnadieu
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
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47
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Rigby LJ, Epa VC, Mackay GA, Hulett MD, Sutton BJ, Gould HJ, Hogarth PM. Domain one of the high affinity IgE receptor, FcepsilonRI, regulates binding to IgE through its interface with domain two. J Biol Chem 2000; 275:9664-72. [PMID: 10734118 DOI: 10.1074/jbc.275.13.9664] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The high affinity receptor for IgE, FcepsilonRI, binds IgE through the second Ig-like domain of the alpha subunit. The role of the first Ig-like domain is not well understood, but it is required for optimal binding of IgE to FcepsilonRI, either through a minor contact interaction or in a supporting structural capacity. The results reported here demonstrate that domain one of FcepsilonRI plays a major structural role supporting the presentation of the ligand-binding site, by interactions generated within the interdomain interface. Analysis of a series of chimeric receptors and point mutants indicated that specific residues within the A' strand of domain one are crucial to the maintenance of the interdomain interface, and IgE binding. Mutation of the Arg(15) and Phe(17) residues caused loss in ligand binding, and utilizing a homology model of FcepsilonRI-alpha based on the solved structure of FcgammaRIIa, it appears likely that this decrease is brought about by collapse of the interface and consequently the IgE-binding site. In addition discrepancies in results of previous studies using chimeric IgE receptors comprising FcepsilonRIalpha with either FcgammaRIIa or FcgammaRIIIA can be explained by the presence or absence of Arg(15) and its influence on the IgE-binding site. The data presented here suggest that the second domain of FcepsilonRI-alpha is the only domain involved in direct contact with the IgE ligand and that domain one has a structural function of great importance in maintaining the integrity of the interdomain interface and, through it, the ligand-binding site.
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Affiliation(s)
- L J Rigby
- Helen M. Schutt Laboratory for Immunology, Austin Research Institute, Kronheimer Building, Austin Repatriation Medical Centre, Heidelberg, Victoria, 3084, Australia
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Kirby I, Davison E, Beavil AJ, Soh CP, Wickham TJ, Roelvink PW, Kovesdi I, Sutton BJ, Santis G. Mutations in the DG loop of adenovirus type 5 fiber knob protein abolish high-affinity binding to its cellular receptor CAR. J Virol 1999; 73:9508-14. [PMID: 10516059 PMCID: PMC112985 DOI: 10.1128/jvi.73.11.9508-9514.1999] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/1999] [Accepted: 07/09/1999] [Indexed: 11/20/2022] Open
Abstract
The amino acid residues in adenovirus type 5 (Ad5) fiber that interact with its cellular receptor, the coxsackie B virus and Ad receptor (CAR), have not been defined. To investigate this, multiple mutations were constructed in the region between residues 479 and 497 in Ad5 fiber (beta-strands E and F and the adjacent region of the DG loop). The effects of these mutations on binding to CAR were determined by use of cell-binding competition experiments, surface plasmon resonance, and direct binding studies. The mutation effects on the overall folding and secondary structure of the protein were assessed by circular dichroism (CD) spectroscopy. Deletions of two consecutive amino acids between residues 485 and 493 abolished high-affinity binding to CAR; the CD spectra indicated that although there was no disruption of the overall folding and secondary structure of the protein, local conformational changes did occur. Moreover, single site mutations in this region of residues with exposed, surface-accessible side chains, such as Thr492, Asn493, and Val495, had no effect on receptor binding, which demonstrates that these residues are not in contact with CAR themselves. This implies the involvement of residues in neighboring loop regions. Replacement of the segment containing the two very short beta-strands E and F and the turn between them (residues 479 to 486) with the corresponding sequence from Ad3 (betaEFAd3-->5 mutation) resulted in the loss of receptor binding. The identical CD spectra for betaEFAd3-->5 and wild-type proteins suggest that these substitutions caused no conformational rearrangement and that the loss of binding may thus be due to the substitution of one or more critical contact residues. These findings have implications for our understanding of the interaction of Ad5 fiber with CAR and for the construction of targeted recombinant Ad5 vectors for gene therapy purposes.
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Affiliation(s)
- I Kirby
- Department of Respiratory Medicine, The Guy's, King's College, Guy's Hospital, London SE1 9RT, United Kingdom
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49
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Affiliation(s)
- S C Garman
- Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, Illinois 60208, USA
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50
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Abstract
The high affinity receptor for immunoglobulin E (designated Fc epsilon RI) is the member of the antigen (Ag) receptor superfamily responsible for linking pathogen-or allergen-specific IgEs with cellular immunologic effector functions. This review provides background information on Fc epsilon RI function combined with more detailed summaries of recent progress in understanding specific aspects of Fc epsilon RI biology and biochemistry. Topics covered include the coordination and function of the large multiprotein signaling complexes that are assembled when Fc epsilon RI and other Ag receptors are engaged, new information on human receptor structures and tissue distribution, and the role of the FcR beta chain in signaling and its potential contribution to atopic phenotypes.
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Affiliation(s)
- J P Kinet
- Harvard Medical School, Boston, Massachusetts, USA.
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