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Heyman B. Antibody feedback regulation. Immunol Rev 2024. [PMID: 39180190 DOI: 10.1111/imr.13377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/26/2024]
Abstract
Antibodies are able to up- or downregulate antibody responses to the antigen they bind. Two major mechanisms can be distinguished. Suppression is most likely caused by epitope masking and can be induced by all isotypes tested (IgG1, IgG2a, IgG2b, IgG3, IgM, and IgE). Enhancement is often caused by the redistribution of antigen in a favorable way, either for presentation to B cells via follicular dendritic cells (IgM and IgG3) or to CD4+ T cells via dendritic cells (IgE, IgG1, IgG2a, and IgG2b). IgM and IgG3 complexes activate complement and are transported from the marginal zone to follicles by marginal zone B cells expressing complement receptors. IgE-antigen complexes are captured by CD23+ B cells in the blood and transported to follicles, delivered to CD8α+ conventional dendritic cells, and presented to CD4+ T cells. Enhancement of antibody responses by IgG1, IgG2a, and IgG2b in complex with proteins requires activating FcγRs. These immune complexes are captured by dendritic cells and presented to CD4+ T cells, subsequently helping cognate B cells. Endogenous feedback regulation influences the response to booster doses of vaccines and passive administration of anti-RhD antibodies is used to prevent alloimmunization of RhD-negative women carrying RhD-positive fetuses.
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Affiliation(s)
- Birgitta Heyman
- Department of Medical Biochemistry and Microbiology, Uppsala University, (BMC), Uppsala, Sweden
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2
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Ramonell RP, Brown M, Woodruff MC, Levy JM, Wise SK, DelGaudio J, Duan M, Saney CL, Kyu S, Cashman KS, Hom JR, Fucile CF, Rosenberg AF, Tipton CM, Sanz I, Gibson GC, Lee FEH. Single-cell analysis of human nasal mucosal IgE antibody secreting cells reveals a newly minted phenotype. Mucosal Immunol 2023; 16:287-301. [PMID: 36931600 PMCID: PMC11227847 DOI: 10.1016/j.mucimm.2023.02.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/27/2022] [Accepted: 02/24/2023] [Indexed: 03/17/2023]
Abstract
Immunoglobulin (Ig) E is central to the pathogenesis of allergic conditions, including allergic fungal rhinosinusitis. However, little is known about IgE antibody secreting cells (ASCs). We performed single-cell RNA sequencing from cluster of differentiation (CD)19+ and CD19- ASCs of nasal polyps from patients with allergic fungal rhinosinusitis (n = 3). Nasal polyps were highly enriched in CD19+ ASCs. Class-switched IgG and IgA ASCs were dominant (95.8%), whereas IgE ASCs were rare (2%) and found only in the CD19+ compartment. Through Ig gene repertoire analysis, IgE ASCs shared clones with IgD-CD27- "double-negative" B cells, IgD+CD27+ unswitched memory B cells, and IgD-CD27+ switched memory B cells, suggesting ontogeny from both IgD+ and memory B cells. Transcriptionally, mucosal IgE ASCs upregulate pathways related to antigen presentation, chemotaxis, B cell receptor stimulation, and survival compared with non-IgE ASCs. Additionally, IgE ASCs have a higher expression of genes encoding lysosomal-associated protein transmembrane 5 (LAPTM5) and CD23, as well as upregulation of CD74 (receptor for macrophage inhibitory factor), store-operated Calcium entry-associated regulatory factor (SARAF), and B cell activating factor receptor (BAFFR), which resemble an early minted ASC phenotype. Overall, these findings reinforce the paradigm that human ex vivo mucosal IgE ASCs have a more immature plasma cell phenotype than other class-switched mucosal ASCs and suggest unique functional roles for mucosal IgE ASCs in concert with Ig secretion.
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Affiliation(s)
- Richard P Ramonell
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | | | - Matthew C Woodruff
- Emory Autoimmunity Center of Excellence, Emory University, Atlanta, Georgia, USA; Department of Medicine, Division of Rheumatology, Lowance Center for Human Immunology, Emory University, Atlanta, Georgia, USA
| | - Joshua M Levy
- Department of Otolaryngology - Head and Neck Surgery, Emory University, Atlanta, Georgia, USA
| | - Sarah K Wise
- Department of Otolaryngology - Head and Neck Surgery, Emory University, Atlanta, Georgia, USA
| | - John DelGaudio
- Department of Otolaryngology - Head and Neck Surgery, Emory University, Atlanta, Georgia, USA
| | - Meixue Duan
- Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Celia L Saney
- College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Shuya Kyu
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Emory University, Atlanta, Georgia, USA
| | - Kevin S Cashman
- Emory Autoimmunity Center of Excellence, Emory University, Atlanta, Georgia, USA; Department of Medicine, Division of Rheumatology, Lowance Center for Human Immunology, Emory University, Atlanta, Georgia, USA
| | - Jennifer R Hom
- Emory Autoimmunity Center of Excellence, Emory University, Atlanta, Georgia, USA; Department of Medicine, Division of Rheumatology, Lowance Center for Human Immunology, Emory University, Atlanta, Georgia, USA
| | - Christopher F Fucile
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA; Informatics Institute, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Alexander F Rosenberg
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA; Informatics Institute, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Christopher M Tipton
- Emory Autoimmunity Center of Excellence, Emory University, Atlanta, Georgia, USA; Department of Medicine, Division of Rheumatology, Lowance Center for Human Immunology, Emory University, Atlanta, Georgia, USA
| | - Ignacio Sanz
- Emory Autoimmunity Center of Excellence, Emory University, Atlanta, Georgia, USA; Department of Medicine, Division of Rheumatology, Lowance Center for Human Immunology, Emory University, Atlanta, Georgia, USA
| | | | - F Eun-Hyung Lee
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Emory University, Atlanta, Georgia, USA.
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3
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McDonnell JM, Dhaliwal B, Sutton BJ, Gould HJ. IgE, IgE Receptors and Anti-IgE Biologics: Protein Structures and Mechanisms of Action. Annu Rev Immunol 2023; 41:255-275. [PMID: 36737596 DOI: 10.1146/annurev-immunol-061020-053712] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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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4
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Preliminary Discovery of Small Molecule Inhibitors of Epidermal Growth Factor Receptor (EGFR) That Bind to the Extracellular Domain. Cancers (Basel) 2022; 14:cancers14153647. [PMID: 35954311 PMCID: PMC9367601 DOI: 10.3390/cancers14153647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 07/20/2022] [Accepted: 07/26/2022] [Indexed: 12/04/2022] Open
Abstract
The Epidermal Growth Factor Receptor (EGFR) is a transmembrane glycoprotein belonging to the protein kinase superfamily. It is composed of an extracellular domain, a transmembrane anchoring region and a cytoplasmic region endowed with tyrosine kinase activity. Genetic mutations of EGFR kinase cause higher activity thereby stimulating downstream signaling pathways that, in turn, impact transcription and cell cycle progression. Due to the involvement of mutant EGFR in tumors and inflammatory diseases, in the past decade, several EGFR inhibitory strategies have been extensively studied, either targeting the extracellular domain (through monoclonal antibodies) or the intracellular kinase domain (through ATP-mimic small molecules). Monoclonal antibodies impair the binding to growth factor, the receptor dimerization, and its activation, whereas small molecules block the intracellular catalytic activity. Herein, we describe the development of a novel small molecule, called DSF-102, that interacts with the extracellular domain of EGFR. When tested in vitro in KRAS mutant A549 cells, it impairs EGFR activity by exerting (i) dose-dependent toxicity effects; (ii) a negative regulation of ERK, MAPK p38 and AKT; and (iii) a modulation of the intracellular trafficking and lysosomal degradation of EGFR. Interestingly, DSF-102 exerts its EGFR inhibitory activity without showing interaction with the intracellular kinase domain. Taken together, these findings suggest that DSF-102 is a promising hit compound for the development of a novel class of anti-EGFR compounds, i.e., small molecules able to interact with the extracellular domain of EGFR and useful for overcoming the KRAS-driven resistance to TKI treatment.
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5
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Engeroff P, Vogel M. The Potential of Exosomes in Allergy Immunotherapy. Vaccines (Basel) 2022; 10:vaccines10010133. [PMID: 35062793 PMCID: PMC8780385 DOI: 10.3390/vaccines10010133] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/12/2022] [Accepted: 01/14/2022] [Indexed: 02/01/2023] Open
Abstract
Allergic diseases represent a global health and economic burden of increasing significance. The lack of disease-modifying therapies besides specific allergen immunotherapy (AIT) which is not available for all types of allergies, necessitates the study of novel therapeutic approaches. Exosomes are small endosome-derived vesicles delivering cargo between cells and thus allowing inter-cellular communication. Since immune cells make use of exosomes to boost, deviate, or suppress immune responses, exosomes are intriguing candidates for immunotherapy. Here, we review the role of exosomes in allergic sensitization and inflammation, and we discuss the mechanisms by which exosomes could potentially be used in immunotherapeutic approaches for the treatment of allergic diseases. We propose the following approaches: (a) Mast cell-derived exosomes expressing IgE receptor FcεRI could absorb IgE and down-regulate systemic IgE levels. (b) Tolerogenic exosomes could suppress allergic immune responses via induction of regulatory T cells. (c) Exosomes could promote TH1-like responses towards an allergen. (d) Exosomes could modulate IgE-facilitated antigen presentation.
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Affiliation(s)
- Paul Engeroff
- Sorbonne Université, INSERM, Immunology-Immunopathology-Immunotherapy (i3), F-75005 Paris, France;
| | - Monique Vogel
- Department of Immunology, University Hospital for Rheumatology, Immunology, and Allergology, 3010 Bern, Switzerland
- Department of BioMedical Research, University of Bern, 3008 Bern, Switzerland
- Correspondence:
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6
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Engeroff P, Vogel M. The role of CD23 in the regulation of allergic responses. Allergy 2021; 76:1981-1989. [PMID: 33378583 PMCID: PMC8359454 DOI: 10.1111/all.14724] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/14/2020] [Accepted: 12/22/2020] [Indexed: 02/06/2023]
Abstract
IgE, the key molecule in atopy has been shown to bind two receptors, FcεRI, the high‐affinity receptor, and FcεRII (CD23), binding IgE with lower affinity. Whereas cross‐linking of IgE on FcεRI expressed by mast cells and basophils triggers the allergic reaction, binding of IgE to CD23 on B cells plays an important role in both IgE regulation and presentation. Furthermore, IgE‐immune complexes (IgE‐ICs) bound by B cells enhance antibody and T cell responses in mice and humans. However, the mechanisms that regulate the targeting of the two receptors and the respective function of the two pathways in inflammation or homeostasis are still a matter of debate. Here, we focus on CD23 and discuss several mechanisms related to IgE binding, as well as the impact of the IgE/antigen‐binding on different immune cells expressing CD23. One recent paper has shown that free IgE preferentially binds to FcεRI whereas IgE‐ICs are preferentially captured by CD23. Binding of IgE‐ICs to CD23 on B cells can, on one hand, regulate serum IgE and prevent effector cell activation and on the other hand facilitate antigen presentation by delivering the antigen to dendritic cells. These data argue for a multifunctional role of CD23 for modulating IgE serum levels and immune responses.
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Affiliation(s)
- Paul Engeroff
- INSERM UMR_S 959 Immunology‐Immunopathology‐Immunotherapy (i3) Sorbonne Université Paris France
| | - Monique Vogel
- Center for Clinical Research Region Västmanland/Uppsala University, Västmanland hospital Västerås Sweden
- Department of BioMedical Research University of Bern Bern Switzerland
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7
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Köhler VK, Crescioli S, Fazekas-Singer J, Bax HJ, Hofer G, Pranger CL, Hufnagl K, Bianchini R, Flicker S, Keller W, Karagiannis SN, Jensen-Jarolim E. Filling the Antibody Pipeline in Allergy: PIPE Cloning of IgE, IgG 1 and IgG 4 against the Major Birch Pollen Allergen Bet v 1. Int J Mol Sci 2020; 21:E5693. [PMID: 32784509 PMCID: PMC7460837 DOI: 10.3390/ijms21165693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/30/2020] [Accepted: 08/06/2020] [Indexed: 01/13/2023] Open
Abstract
Birch pollen allergy is among the most prevalent pollen allergies in Northern and Central Europe. This IgE-mediated disease can be treated with allergen immunotherapy (AIT), which typically gives rise to IgG antibodies inducing tolerance. Although the main mechanisms of allergen immunotherapy (AIT) are known, questions regarding possible Fc-mediated effects of IgG antibodies remain unanswered. This can mainly be attributed to the unavailability of appropriate tools, i.e., well-characterised recombinant antibodies (rAbs). We hereby aimed at providing human rAbs of several classes for mechanistic studies and as possible candidates for passive immunotherapy. We engineered IgE, IgG1, and IgG4 sharing the same variable region against the major birch pollen allergen Bet v 1 using Polymerase Incomplete Primer Extension (PIPE) cloning. We tested IgE functionality and IgG blocking capabilities using appropriate model cell lines. In vitro studies showed IgE engagement with FcεRI and CD23 and Bet v 1-dependent degranulation. Overall, we hereby present fully functional, human IgE, IgG1, and IgG4 sharing the same variable region against Bet v 1 and showcase possible applications in first mechanistic studies. Furthermore, our IgG antibodies might be useful candidates for passive immunotherapy of birch pollen allergy.
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Affiliation(s)
- Verena K. Köhler
- Comparative Medicine, The Interuniversity Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University Vienna and University Vienna, Veterinärplatz 1, 1210 Vienna, Austria; (V.K.K.); (J.F.-S.); (C.L.P.); (K.H.); (R.B.)
- Institute of Pathophysiology and Allergy Research, Centre of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Währinger Gürtel 18–20, 1090 Vienna, Austria;
| | - Silvia Crescioli
- St. John’s Institute of Dermatology, School of Basic & Medical Biosciences, King’s College London, 9th Floor, Tower Wing, Guy’s Hospital, London SE1 9RT, UK; (S.C.); (H.J.B.); (S.N.K.)
- NIHR Biomedical Research Centre at Guy’s and St Thomas’s Hospitals and King’s College London, Guy’s Hospital, London SE1 9RT, UK
| | - Judit Fazekas-Singer
- Comparative Medicine, The Interuniversity Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University Vienna and University Vienna, Veterinärplatz 1, 1210 Vienna, Austria; (V.K.K.); (J.F.-S.); (C.L.P.); (K.H.); (R.B.)
- Institute of Pathophysiology and Allergy Research, Centre of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Währinger Gürtel 18–20, 1090 Vienna, Austria;
| | - Heather J. Bax
- St. John’s Institute of Dermatology, School of Basic & Medical Biosciences, King’s College London, 9th Floor, Tower Wing, Guy’s Hospital, London SE1 9RT, UK; (S.C.); (H.J.B.); (S.N.K.)
- School of Cancer & Pharmaceutical Sciences, King’s College London, 9th Floor, Tower Wing, Guy’s Hospital, London SE1 9RT, UK
| | - Gerhard Hofer
- Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Humboldtstraße 50, 8010 Graz, Austria; (G.H.); (W.K.)
| | - Christina L. Pranger
- Comparative Medicine, The Interuniversity Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University Vienna and University Vienna, Veterinärplatz 1, 1210 Vienna, Austria; (V.K.K.); (J.F.-S.); (C.L.P.); (K.H.); (R.B.)
- Institute of Pathophysiology and Allergy Research, Centre of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Währinger Gürtel 18–20, 1090 Vienna, Austria;
| | - Karin Hufnagl
- Comparative Medicine, The Interuniversity Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University Vienna and University Vienna, Veterinärplatz 1, 1210 Vienna, Austria; (V.K.K.); (J.F.-S.); (C.L.P.); (K.H.); (R.B.)
- Institute of Pathophysiology and Allergy Research, Centre of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Währinger Gürtel 18–20, 1090 Vienna, Austria;
| | - Rodolfo Bianchini
- Comparative Medicine, The Interuniversity Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University Vienna and University Vienna, Veterinärplatz 1, 1210 Vienna, Austria; (V.K.K.); (J.F.-S.); (C.L.P.); (K.H.); (R.B.)
- Institute of Pathophysiology and Allergy Research, Centre of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Währinger Gürtel 18–20, 1090 Vienna, Austria;
| | - Sabine Flicker
- Institute of Pathophysiology and Allergy Research, Centre of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Währinger Gürtel 18–20, 1090 Vienna, Austria;
| | - Walter Keller
- Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Humboldtstraße 50, 8010 Graz, Austria; (G.H.); (W.K.)
| | - Sophia N. Karagiannis
- St. John’s Institute of Dermatology, School of Basic & Medical Biosciences, King’s College London, 9th Floor, Tower Wing, Guy’s Hospital, London SE1 9RT, UK; (S.C.); (H.J.B.); (S.N.K.)
- NIHR Biomedical Research Centre at Guy’s and St Thomas’s Hospitals and King’s College London, Guy’s Hospital, London SE1 9RT, UK
- Breast Cancer Now Research Unit, School of Cancer & Pharmaceutical Sciences, King’s College London, Guy’s Cancer Centre, London SE1 9RT, UK
| | - Erika Jensen-Jarolim
- Comparative Medicine, The Interuniversity Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University Vienna and University Vienna, Veterinärplatz 1, 1210 Vienna, Austria; (V.K.K.); (J.F.-S.); (C.L.P.); (K.H.); (R.B.)
- Institute of Pathophysiology and Allergy Research, Centre of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Währinger Gürtel 18–20, 1090 Vienna, Austria;
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Nagamachi A, Kikuchi J, Kanai A, Furukawa Y, Inaba T. Kinetics of cytokine receptor internalization under steady-state conditions affects growth of neighboring blood cells. Haematologica 2019; 105:e325-e327. [PMID: 31672901 DOI: 10.3324/haematol.2019.232959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Akiko Nagamachi
- Department of Molecular Oncology and Leukemia Program Project, Research Institute for Radiation Biology & Medicine, Hiroshima University, Minami-ku, Hiroshima
| | - Jiro Kikuchi
- Division of Stem Cell Regulation, Center for Molecular Medicine, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, Japan
| | - Akinori Kanai
- Department of Molecular Oncology and Leukemia Program Project, Research Institute for Radiation Biology & Medicine, Hiroshima University, Minami-ku, Hiroshima
| | - Yusuke Furukawa
- Division of Stem Cell Regulation, Center for Molecular Medicine, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, Japan
| | - Toshiya Inaba
- Department of Molecular Oncology and Leukemia Program Project, Research Institute for Radiation Biology & Medicine, Hiroshima University, Minami-ku, Hiroshima
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Fukano C, Ohashi-Doi K, Lund K, Nakao A, Masuyama K, Matsuoka T. Establishment of enzyme-linked immunosorbent facilitated antigen binding as a biomarker assay for Japanese cedar pollen allergy immunotherapy. J Pharmacol Sci 2019; 140:223-227. [PMID: 31353210 DOI: 10.1016/j.jphs.2019.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 06/21/2019] [Accepted: 06/25/2019] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Clinical efficacy of allergen-specific Immunotherapy (AIT) towards Japanese cedar (JC) pollen allergy is firmly established but JC pollen-specific biomarker assays are lacking. Treatment-related increase of allergen-specific antibodies is a robust biomarker of successful AIT. Allergen-specific non-IgE antibodies are believed to reduce the effects of allergen exposure by competing with IgE for allergen binding, and in-vitro assays quantifying the effects of AIT-induced IgE-blocking antibodies are advantageous. A cell-free enzyme-linked immunosorbent facilitated antigen binding (ELIFAB) assay of JC pollen was established. METHODS Serum IgE-allergen complexes were captured by immobilized recombinant CD23, and allergen-IgE-CD23 complexes were detected by a biotin-conjugated anti-human IgE antibody. Sera from JC pollen-allergic subjects without or with subcutaneous immunotherapy (SCIT) with JC pollen extract were used (n = 11/group). RESULTS Optimal assay conditions were established at 20 μg/mL CD23 and 0.3 μg/mL JC pollen extract, and the dependency on CD23 and IgE was verified. The data show that the JC pollen ELIFAB assay is fit for purpose and demonstrates that the IgE-blocking activity is significantly increased in the JC pollen SCIT group compared with the non-treated group. CONCLUSION The JC pollen ELIFAB assay represents a simple, cell-free biomarker assay for monitoring the development of IgE-blocking antibody activity during JC pollen AIT.
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Affiliation(s)
- Chiharu Fukano
- Research Laboratory, Torii Pharmaceutical Co., Ltd., 2183-1 Ota Teranosaku, Sakura-shi, Chiba, Japan; Department of Immunology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo-shi, Yamanashi, Japan
| | - Katsuyo Ohashi-Doi
- Research Laboratory, Torii Pharmaceutical Co., Ltd., 2183-1 Ota Teranosaku, Sakura-shi, Chiba, Japan.
| | - Kaare Lund
- Papermill Medical, Ole Maaløes Vej 3, DK-2200 Copenhagen N, Denmark
| | - Atsuhito Nakao
- Department of Immunology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo-shi, Yamanashi, Japan
| | - Keisuke Masuyama
- Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo-shi, Yamanashi, Japan
| | - Tomokazu Matsuoka
- Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo-shi, Yamanashi, Japan
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10
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Demock M, Kornguth S. A Mechanism for the Development of Chronic Traumatic Encephalopathy From Persistent Traumatic Brain Injury. J Exp Neurosci 2019; 13:1179069519849935. [PMID: 31205424 PMCID: PMC6537483 DOI: 10.1177/1179069519849935] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/22/2019] [Indexed: 12/24/2022] Open
Abstract
A mechanism that describes the progression of traumatic brain injury (TBI) to end-stage chronic traumatic encephalopathy (CTE) is offered in this article. This mechanism is based upon the observed increase in the concentration of both tau protein and of human leukocyte antigen (HLA) class I proteins; the HLA increase is expressed on the cell membrane of neural cells. These events follow the inflammatory responses caused by the repetitive TBI. Associated inflammatory changes include macrophage entry into the brain parenchyma from increased permeability of the blood-brain barrier (BBB) and microglial activation at the base of the sulci. The release of interferon gamma from the microglia and macrophages induces the marked increased expression of HLA class I proteins by the neural cells and subsequent redistribution of the tau proteins to the glial and neuronal surface. In those individuals with highly expressed HLA class I C, the high level of HLA binds tau protein electrostatically. The ionic region of HLA class I C (amino acid positions 50-90) binds to the oppositely charged ionic region of tau (amino acid positions 93-133). These interactions thereby shift the cellular localization of the tau and orient the tau spatially so that the cross-linking sites of tau (275-280 and 306-311) are aligned. This alignment facilitates the cross-linking of tau to form the intracellular and extracellular microfibrils of tau, the primary physiological characteristic of tauopathy. Following endocytosis of the membrane HLA/tau complex, these microfibrils accumulate and produce a tau-storage-like disease. Therefore, tauopathy is the secondary collateral process of brain injury, resulting from the substantial increase in tau and HLA expression on neural cells. This proposed mechanism suggests several potential targets for mitigating the clinical progression of TBI to CTE.
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Affiliation(s)
- Melissa Demock
- Department of Chemistry, The University of Texas at Austin, Austin, TX, USA
| | - Steven Kornguth
- Departments of Neurology and Kinesiology and Health Education, The University of Texas at Austin, Austin, TX, USA.,Departments of Neurology and Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
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11
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Clarke S, Nagan Y, Prinsloo E, Oosthuizen V. An acidic loop within the human soluble CD23 protein may direct the interaction between sCD23 and the α Xβ 2 integrin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:548-555. [PMID: 30902766 DOI: 10.1016/j.bbapap.2019.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/02/2019] [Accepted: 03/14/2019] [Indexed: 11/18/2022]
Abstract
CD23 is involved in a myriad of immune reactions. It is not only a receptor for IgE, but also functions in the regulation of IgE synthesis, isotype switching in B cells, and induction of the inflammatory response. These effector functions of CD23 arise through its interaction with another leukocyte-specific cell surface receptor - the β2 integrin subfamily. It has been shown that CD23 is also capable of interacting with the β3 and β5 integrin β-subunit of integrins via a basic RKC motif in a metal cation-independent fashion. In this study the interaction was probed for whether or not the RKC motif governs the interaction between CD23 and the αXβ2 integrin as well. This was done by performing bioinformatic docking predictions between CD23 and αXβ2 integrin αI domain and SPR spectroscopy analysis of the interaction. This revealed that in the absence of cations, the RKC motif is involved in interaction with the integrin αI domain. However, in the presence of divalent metal cations the interaction showed the involvement of a novel acidic motif within the CD23 protein. This same pattern of interaction was seen in docking predictions between CD23 and the β3I-like domain. This study thus presents an alternative site as a possible contributor to the CD23-integrin interaction exhibiting cation-dependence.
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Affiliation(s)
- Stephen Clarke
- Nelson Mandela University, Faculty of Science, Department of Biochemistry and Microbiology, South Africa.
| | - Yurisha Nagan
- Nelson Mandela University, Faculty of Science, Department of Biochemistry and Microbiology, South Africa
| | - Earl Prinsloo
- Rhodes University, Faculty of Science, Department of Biochemistry and Microbiology, South Africa
| | - Vaughan Oosthuizen
- Nelson Mandela University, Faculty of Science, Department of Biochemistry and Microbiology, South Africa
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12
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Sutton BJ, Davies AM, Bax HJ, Karagiannis SN. IgE Antibodies: From Structure to Function and Clinical Translation. Antibodies (Basel) 2019; 8:E19. [PMID: 31544825 PMCID: PMC6640697 DOI: 10.3390/antib8010019] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 02/11/2019] [Accepted: 02/15/2019] [Indexed: 12/15/2022] Open
Abstract
Immunoglobulin E (IgE) antibodies are well known for their role in mediating allergic reactions, and their powerful effector functions activated through binding to Fc receptors FcεRI and FcεRII/CD23. Structural studies of IgE-Fc alone, and when bound to these receptors, surprisingly revealed not only an acutely bent Fc conformation, but also subtle allosteric communication between the two distant receptor-binding sites. The ability of IgE-Fc to undergo more extreme conformational changes emerged from structures of complexes with anti-IgE antibodies, including omalizumab, in clinical use for allergic disease; flexibility is clearly critical for IgE function, but may also be exploited by allosteric interference to inhibit IgE activity for therapeutic benefit. In contrast, the power of IgE may be harnessed to target cancer. Efforts to improve the effector functions of therapeutic antibodies for cancer have almost exclusively focussed on IgG1 and IgG4 subclasses, but IgE offers an extremely high affinity for FcεRI receptors on immune effector cells known to infiltrate solid tumours. Furthermore, while tumour-resident inhibitory Fc receptors can modulate the effector functions of IgG antibodies, no inhibitory IgE Fc receptors are known to exist. The development of tumour antigen-specific IgE antibodies may therefore provide an improved immune functional profile and enhanced anti-cancer efficacy. We describe proof-of-concept studies of IgE immunotherapies against solid tumours, including a range of in vitro and in vivo evaluations of efficacy and mechanisms of action, as well as ex vivo and in vivo safety studies. The first anti-cancer IgE antibody, MOv18, the clinical translation of which we discuss herein, has now reached clinical testing, offering great potential to direct this novel therapeutic modality against many other tumour-specific antigens. This review highlights how our understanding of IgE structure and function underpins these exciting clinical developments.
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Affiliation(s)
- Brian J Sutton
- King's College London, Randall Centre for Cell and Molecular Biophysics, London SE1 1UL, UK.
- Asthma UK Centre in Allergic Mechanisms of Asthma, London, UK.
| | - Anna M Davies
- King's College London, Randall Centre for Cell and Molecular Biophysics, London SE1 1UL, UK.
- Asthma UK Centre in Allergic Mechanisms of Asthma, London, UK.
| | - Heather J Bax
- King's College London, St John's Institute of Dermatology, London SE1 9RT, UK.
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Peng W, Grobe W, Walgenbach-Brünagel G, Flicker S, Yu C, Sylvester M, Allam JP, Oldenburg J, Garbi N, Valenta R, Novak N. Distinct Expression and Function of FcεRII in Human B Cells and Monocytes. THE JOURNAL OF IMMUNOLOGY 2017; 198:3033-3044. [DOI: 10.4049/jimmunol.1601028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 02/14/2017] [Indexed: 01/25/2023]
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14
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Sánchez-Gómez FJ, González-Morena JM, Vida Y, Pérez-Inestrosa E, Blanca M, Torres MJ, Pérez-Sala D. Amoxicillin haptenates intracellular proteins that can be transported in exosomes to target cells. Allergy 2017; 72:385-396. [PMID: 27319758 DOI: 10.1111/all.12958] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2016] [Indexed: 12/17/2022]
Abstract
BACKGROUND Allergic reactions to β-lactams are among the most frequent causes of drug allergy and constitute an important clinical problem. Drug covalent binding to endogenous proteins (haptenation) is thought to be required for activation of the immune system. Nevertheless, neither the nature nor the role of the drug protein targets involved in this process is fully understood. Here, we aim to identify novel intracellular targets for haptenation by amoxicillin (AX) and their cellular fate. METHODS We have treated B lymphocytes with either AX or a biotinylated analog (AX-B). The identification of protein targets for haptenation by AX has been approached by mass spectrometry and immunoaffinity techniques. In addition, intercellular communication mediated by the delivery of vesicles loaded with AX-B-protein adducts has been explored by microscopy techniques. RESULTS We have observed a complex pattern of AX-haptenated proteins. Several novel targets for haptenation by AX in B lymphocytes have been identified. AX-haptenated proteins were detected in cell lysates and extracellularly, either as soluble proteins or in lymphocyte-derived extracellular vesicles. Interestingly, exosomes from AX-B-treated cells showed a positive biotin signal in electron microscopy. Moreover, they were internalized by endothelial cells, thus supporting their involvement in intercellular transfer of haptenated proteins. CONCLUSIONS These results represent the first identification of AX-mediated haptenation of intracellular proteins. Moreover, they show that exosomes can constitute a novel vehicle for haptenated proteins, and raise the hypothesis that they could provide antigens for activation of the immune system during the allergic response.
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Affiliation(s)
- F. J. Sánchez-Gómez
- Department of Chemical and Physical Biology; Centro de Investigaciones Biológicas; CSIC; Madrid Spain
| | - J. M. González-Morena
- Department of Chemical and Physical Biology; Centro de Investigaciones Biológicas; CSIC; Madrid Spain
| | - Y. Vida
- Department of Organic Chemistry; University of Málaga; IBIMA; Málaga Spain
- Andalusian Center for Nanomedicine and Biotechnology-BIONAND; Parque Tecnológico de Andalucía; Málaga Spain
| | - E. Pérez-Inestrosa
- Department of Organic Chemistry; University of Málaga; IBIMA; Málaga Spain
- Andalusian Center for Nanomedicine and Biotechnology-BIONAND; Parque Tecnológico de Andalucía; Málaga Spain
| | - M. Blanca
- Allergy Unit; IBIMA-Regional University Hospital of Málaga; UMA; Málaga Spain
| | - M. J. Torres
- Allergy Unit; IBIMA-Regional University Hospital of Málaga; UMA; Málaga Spain
| | - D. Pérez-Sala
- Department of Chemical and Physical Biology; Centro de Investigaciones Biológicas; CSIC; Madrid Spain
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15
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Dumont C, Czuba E, Chen M, Villadangos JA, Johnston AP, Mintern JD. DNA‐based probes for flow cytometry analysis of endocytosis and recycling. Traffic 2017; 18:242-249. [DOI: 10.1111/tra.12466] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 12/21/2016] [Accepted: 12/21/2016] [Indexed: 01/04/2023]
Affiliation(s)
- Claire Dumont
- Department of Biochemistry and Molecular Biology The University of Melbourne, Bio21 Molecular Science and Biotechnology Institute Parkville Victoria Australia
| | - Ewa Czuba
- Drug Delivery, Disposition and Dynamics Monash Institute of Pharmaceutical Sciences, Monash University Parkville Victoria Australia
| | - Moore Chen
- Drug Delivery, Disposition and Dynamics Monash Institute of Pharmaceutical Sciences, Monash University Parkville Victoria Australia
| | - Jose A. Villadangos
- Department of Biochemistry and Molecular Biology The University of Melbourne, Bio21 Molecular Science and Biotechnology Institute Parkville Victoria Australia
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity The University of Melbourne Parkville Victoria Australia
| | - Angus P.R. Johnston
- Drug Delivery, Disposition and Dynamics Monash Institute of Pharmaceutical Sciences, Monash University Parkville Victoria Australia
- ARC Centre of Excellence in Convergent Bio‐Nano Science and Technology Monash University Parkville Australia
| | - Justine D. Mintern
- Department of Biochemistry and Molecular Biology The University of Melbourne, Bio21 Molecular Science and Biotechnology Institute Parkville Victoria Australia
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16
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Kelly BT, Grayson MH. Immunoglobulin E, what is it good for? Ann Allergy Asthma Immunol 2016; 116:183-7. [PMID: 26945494 DOI: 10.1016/j.anai.2015.10.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 10/15/2015] [Accepted: 10/20/2015] [Indexed: 12/18/2022]
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17
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Selb R, Eckl-Dorna J, Neunkirchner A, Schmetterer K, Marth K, Gamper J, Jahn-Schmid B, Pickl WF, Valenta R, Niederberger V. CD23 surface density on B cells is associated with IgE levels and determines IgE-facilitated allergen uptake, as well as activation of allergen-specific T cells. J Allergy Clin Immunol 2016; 139:290-299.e4. [PMID: 27372566 DOI: 10.1016/j.jaci.2016.03.042] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 02/17/2016] [Accepted: 03/02/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND Increasing evidence suggests that the low-affinity receptor for IgE, CD23, plays an important role in controlling the activity of allergen-specific T cells through IgE-facilitated allergen presentation. OBJECTIVE We sought to determine the number of CD23 molecules on immune cells in allergic patients and to investigate whether the number of CD23 molecules on antigen-presenting cells is associated with IgE levels and influences allergen uptake and allergen-specific T-cell activation. METHODS Numbers of CD23 molecules on immune cells of allergic patients were quantified by using flow cytometry with QuantiBRITE beads and compared with total and allergen-specific IgE levels, as well as with allergen-induced immediate skin reactivity. Allergen uptake and allergen-specific T-cell activation in relation to CD23 surface density were determined by using flow cytometry in combination with confocal microscopy and T cells transfected with the T-cell receptor specific for the birch pollen allergen Bet v 1, respectively. Defined IgE-allergen immune complexes were formed with human monoclonal allergen-specific IgE and Bet v 1. RESULTS In allergic patients the vast majority of CD23 molecules were expressed on naive IgD+ B cells. The density of CD23 molecules on B cells but not the number of CD23+ cells correlated with total IgE levels (RS = 0.53, P = .03) and allergen-induced skin reactions (RS = 0.63, P = .008). Uptake of allergen-IgE complexes into B cells and activation of allergen-specific T cells depended on IgE binding to CD23 and were associated with CD23 surface density. Addition of monoclonal IgE to cultured PBMCs significantly (P = .04) increased CD23 expression on B cells. CONCLUSION CD23 surface density on B cells of allergic patients is correlated with allergen-specific IgE levels and determines allergen uptake and subsequent activation of T cells.
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Affiliation(s)
- Regina Selb
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
| | - Julia Eckl-Dorna
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
| | - Alina Neunkirchner
- Christian Doppler Laboratory for Immunomodulation, Medical University of Vienna, Vienna, Austria; Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Klaus Schmetterer
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Katharina Marth
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Jutta Gamper
- Section for Medical Statistics, Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Beatrice Jahn-Schmid
- Division of Experimental Allergology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Winfried F Pickl
- Christian Doppler Laboratory for Immunomodulation, Medical University of Vienna, Vienna, Austria; Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Rudolf Valenta
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Verena Niederberger
- Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria.
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18
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Sutton BJ, Davies AM. Structure and dynamics of IgE-receptor interactions: FcεRI and CD23/FcεRII. Immunol Rev 2015; 268:222-35. [DOI: 10.1111/imr.12340] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Brian J. Sutton
- Randall Division of Cell and Molecular Biophysics; King's College London; London UK
- Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma; London UK
| | - Anna M. Davies
- Randall Division of Cell and Molecular Biophysics; King's College London; London UK
- Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma; London UK
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19
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Abstract
The pathogenic role of immunoglobulin E (IgE) antibodies in triggering and maintaining allergic inflammation in response to allergens is due to the binding of multivalent allergens to allergen-specific IgEs on sensitized effector cells. These interactions trigger effector cell activation, resulting in release of potent inflammatory mediators, recruitment of inflammatory cells, antigen presentation, and production of allergen-specific antibody responses. Since its discovery in the 1960s, the central role of IgE in allergic disease has been intensively studied, placing IgE and its functions at the heart of therapeutic efforts for the treatment of allergies. Here, we provide an overview of the nature, roles, and significance of IgE antibodies in allergic diseases, infections, and inflammation and the utility of antibodies as therapies. We place special emphasis on allergen-IgE-Fcε receptor complexes in the context of allergic and inflammatory diseases and describe strategies, including monoclonal antibodies, aimed at interrupting these complexes. Of clinical significance, one antibody, omalizumab, is presently in clinical use and works by preventing formation of IgE-Fcε receptor interactions. Active immunotherapy approaches with allergens and allergen derivatives have also demonstrated clinical benefits for patients with allergic diseases. These treatments are strongly associated with serum increases of IgE-neutralizing antibodies and feature a notable redirection of humoral responses towards production of antibodies of the IgG4 subclass in patients receiving immunotherapies. Lastly, we provide a new perspective on the rise of recombinant antibodies of the IgE class recognizing tumor-associated antigens, and we discuss the potential utility of tumor antigen-specific IgE antibodies to direct potent IgE-driven immune responses against tumors.
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20
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Fellmann M, Buschor P, Röthlisberger S, Zellweger F, Vogel M. High affinity targeting of CD23 inhibits IgE synthesis in human B cells. IMMUNITY INFLAMMATION AND DISEASE 2015; 3:339-49. [PMID: 26732048 PMCID: PMC4693728 DOI: 10.1002/iid3.72] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 05/19/2015] [Accepted: 06/08/2015] [Indexed: 12/17/2022]
Abstract
The low‐affinity IgE receptor FcϵRII (CD23) is part of the regulatory system controlling IgE synthesis in human B cells and exists in membrane and soluble forms. Binding of IgE to CD23 has been described to have stabilizing effects and to prevent cleavage of CD23. Previous experiments using anti‐CD23 antibodies reduced IgE synthesis but were difficult to interpret as the antibody Fc part might also mediate feedback mechanisms. The purpose of this study was to investigate the regulatory role of CD23, by using designed ankyrin repeat proteins (DARPins) that specifically recognize CD23. Anti‐CD23 DARPins were isolated by ribosome display and were produced as monovalent and bivalent constructs. Affinities to CD23 were measured by surface plasmon resonance. IgE synthesis and up‐regulation of CD23 in human peripheral B cells were induced by IL‐4 and anti‐CD40 antibody. We assessed CD23 expression and its stabilization by FACS and used an ELISA for detecting soluble CD23. IgE synthesis was measured by ELISA and real‐time PCR. Surface plasmon resonance revealed affinities of the DARPins to CD23 in the pico‐molar range. Anti‐CD23 DARPins strongly inhibited binding of IgE to CD23 and share thus a similar binding epitope as IgE. The DARPins stabilized membrane CD23 and reduced IgE synthesis in an isotype specific manner. Furthermore, the anti‐CD23 DARPins decreased IgE transcript through inhibition of mature Cϵ RNA synthesis suggesting a posttranscriptional control mechanism. This study demonstrates that targeting CD23 alone is sufficient to inhibit IgE synthesis and suggests that a negative signaling occurs directly through the CD23 molecule.
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Affiliation(s)
- Marc Fellmann
- Department of Immunology, University Clinic RIA University of Bern Inselspital Switzerland
| | - Patrick Buschor
- Department of Immunology, University Clinic RIA University of Bern Inselspital Switzerland
| | - Silvan Röthlisberger
- Department of Immunology, University Clinic RIA University of Bern Inselspital Switzerland
| | - Fabian Zellweger
- Department of Immunology, University Clinic RIA University of Bern Inselspital Switzerland
| | - Monique Vogel
- Department of Immunology, University Clinic RIA University of Bern Inselspital Switzerland
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21
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Chan MA, Gigliotti NM, Aubin BG, Rosenwasser LJ. FCER2 (CD23) asthma-related single nucleotide polymorphisms yields increased IgE binding and Egr-1 expression in human B cells. Am J Respir Cell Mol Biol 2014; 50:263-9. [PMID: 24010859 DOI: 10.1165/rcmb.2013-0112oc] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
CD23 is the low-affinity Fc receptor for IgE. When expressed on B cells, CD23 appears to play a role in regulation of IgE synthesis. Polymorphisms within FCER2, the gene encoding CD23, have been associated with atopy, increased risk of exacerbations in patients with asthma, and high serum IgE levels. A single-nucleotide polymorphism (rs2228137) present in exon 4 of FCER2 encodes a nonsynonymous amino acid change (R62W) and is the subject of the present analysis. Human B cell stable transfectants were established to characterize the functional relevance of the R62W SNP. We demonstrate that CD23b-R62W-expressing human B cells bind IgE with greater affinity than wild-type cells and display differences in kinetics of CD23-mediated ERK1/2 activation that may be responsible for the increased levels of Egr-1 mRNA observed after stimulation through CD23. Finally, the R62W SNP seems to alter the tertiary or quaternary structure of CD23 because in the absence of N-glycosylation the CD23b-R62W-expressing cells appear to be less sensitive to endogenous proteases. These observations may have implications in mechanisms responsible for the atopic phenotypes observed in patients with asthma who possess this genotype.
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Affiliation(s)
- Marcia A Chan
- Department of Pediatrics, Division of Immunology Research, Children's Mercy Hospitals & Clinics, Kansas City, Missouri
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22
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Targeting antigens to dendritic cell receptors for vaccine development. JOURNAL OF DRUG DELIVERY 2013; 2013:869718. [PMID: 24228179 PMCID: PMC3817681 DOI: 10.1155/2013/869718] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 07/11/2013] [Indexed: 12/30/2022]
Abstract
Dendritic cells (DCs) are highly specialized antigen presenting cells of the immune system which play a key role in regulating immune responses. Depending on the method of antigen delivery, DCs stimulate immune responses or induce tolerance. As a consequence of the dual function of DCs, DCs are studied in the context of immunotherapy for both cancer and autoimmune diseases. In vaccine development, a major aim is to induce strong, specific T-cell responses. This is achieved by targeting antigen to cell surface molecules on DCs that efficiently channel the antigen into endocytic compartments for loading onto MHC molecules and stimulation of T-cell responses. The most attractive cell surface receptors, expressed on DCs used as targets for antigen delivery for cancer and other diseases, are discussed.
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23
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Potaczek DP, Kabesch M. Current concepts of IgE regulation and impact of genetic determinants. Clin Exp Allergy 2013; 42:852-71. [PMID: 22909159 DOI: 10.1111/j.1365-2222.2011.03953.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Immunoglobulin E (IgE) mediated immune responses seem to be directed against parasites and neoplasms, but are best known for their involvement in allergies. The IgE network is tightly controlled at different levels as outlined in this review. Genetic determinants were suspected to influence IgE regulation and IgE levels considerably for many years. Linkage and candidate gene studies suggested a number of loci and genes to correlate with total serum IgE levels, and recently genome-wide association studies (GWAS) provided the power to identify genetic determinants for total serum IgE levels: 1q23 (FCER1A), 5q31 (RAD50, IL13, IL4), 12q13 (STAT6), 6p21.3 (HLA-DRB1) and 16p12 (IL4R, IL21R). In this review, we analyse the potential role of these GWAS hits in the IgE network and suggest mechanisms of how genes and genetic variants in these loci may influence IgE regulation.
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Affiliation(s)
- D P Potaczek
- Department of Pediatric Pneumology, Allergy and Neonatology, Hannover Medical School, Hannover, Germany
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25
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Dullaers M, De Bruyne R, Ramadani F, Gould HJ, Gevaert P, Lambrecht BN. The who, where, and when of IgE in allergic airway disease. J Allergy Clin Immunol 2011; 129:635-45. [PMID: 22168998 DOI: 10.1016/j.jaci.2011.10.029] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 10/18/2011] [Accepted: 10/19/2011] [Indexed: 02/07/2023]
Abstract
Allergic asthma and allergic rhinitis/conjunctivitis are characterized by a T(H)2-dominated immune response associated with increased serum IgE levels in response to inhaled allergens. Because IgE is a key player in the induction and maintenance of allergic inflammation, it represents a prime target for therapeutic intervention. However, our understanding of IgE biology remains fragmentary. This article puts together our current knowledge on IgE in allergic airway diseases with a special focus on the identity of IgE-secreting cells ("who"), their location ("where"), and the circumstances in which they are induced ("when"). We further consider the therapeutic implications of the insights gained.
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Affiliation(s)
- Melissa Dullaers
- Laboratorium of Immunoregulation and Mucosal Immunology, Department of Pulmonary Medicine, University Hospital Ghent, Ghent, Belgium.
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26
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Chan MA, Gigliotti NM, Meng J, Rosenwasser LJ. Asthma-related SNP in FCER2 is associated with increased expression of IL-4R on human B cells. Int J Immunogenet 2011; 38:533-8. [PMID: 22059556 DOI: 10.1111/j.1744-313x.2011.01043.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A SNP (rs2228137) (R62W) in FCER2 has been linked with severe exacerbations in asthmatics. Transfectants expressing the SNP exhibited increased IL-4Rα expression after stimulation through CD23 compared with wild-type. Our data suggest that the SNP may favour increased IgE production through increased responsiveness to IL-4 in patients possessing this genotype.
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Affiliation(s)
- M A Chan
- Department of Pediatric Immunology, Children's Mercy Hospital, Kansas City, MO, USA.
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27
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Burton OT, Oettgen HC. Beyond immediate hypersensitivity: evolving roles for IgE antibodies in immune homeostasis and allergic diseases. Immunol Rev 2011; 242:128-43. [PMID: 21682742 DOI: 10.1111/j.1600-065x.2011.01024.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Immunoglobulin E (IgE) antibodies have long been recognized as the antigen-specific triggers of allergic reactions. This review briefly introduces the established functions of IgE in immediate hypersensitivity and then focuses on emerging evidence from our own investigations as well as those of others that IgE plays important roles in protective immunity against parasites and exerts regulatory influences in the expression of its own receptors, FcεRI and CD23, as well as controlling mast cell homeostasis. We provide an overview of the multifaceted ways in which IgE antibodies contribute to the pathology of food allergy and speculate regarding potential mechanisms of action of IgE blockade.
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Affiliation(s)
- Oliver T Burton
- Division of Immunology, Children's Hospital, Harvard Medical School, Boston, MA, USA.
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28
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Rudman SM, Josephs DH, Cambrook H, Karagiannis P, Gilbert AE, Dodev T, Hunt J, Koers A, Montes A, Taams L, Canevari S, Figini M, Blower PJ, Beavil AJ, Nicodemus CF, Corrigan C, Kaye SB, Nestle FO, Gould HJ, Spicer JF, Karagiannis SN. Harnessing engineered antibodies of the IgE class to combat malignancy: initial assessment of FcɛRI-mediated basophil activation by a tumour-specific IgE antibody to evaluate the risk of type I hypersensitivity. Clin Exp Allergy 2011; 41:1400-13. [PMID: 21569129 DOI: 10.1111/j.1365-2222.2011.03770.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND IgE antibodies, sequestered into tissues and retained locally by the high-affinity IgE receptor, FcɛRI, on powerful effector cells such as mast cells, macrophages and eosinophils, may offer improvements in the therapy of solid tumours. The chimeric antibody, MOv18 IgE, against the human ovarian carcinoma antigen, folate receptor α (FRα), is more effective than its IgG1 counterpart in xenograft models of ovarian cancer. Although MOv18 IgE binds to a single epitope on FRα and cannot cross-link IgE receptors on basophils, there remains a risk that components in the circulation of ovarian cancer patients might cross-link FRα-MOv18-IgE-receptor-FcɛRI complexes on basophils to cause type I hypersensitivity. OBJECTIVE To assess the propensity for MOv18 used in a therapeutic setting to cause FcɛRI-mediated type I hypersensitivity. METHODS As validated readouts of the potential for MOv18 to cause FcɛRI-mediated type I hypersensitivity we measured release of a granule-stored mediator from a rat basophilic leukaemia cell line RBL SX-38 stably transfected with human tetrameric (αβγ2) FcɛRI, and induction of CD63 on blood basophils from patients with ovarian carcinoma and healthy controls ex vivo. RESULTS Serum FRα levels were increased in ovarian cancer patients compared with healthy controls. MOv18 IgE alone, or in the presence of its antigen recombinant human FRα, or of healthy volunteer (n=14) or ovarian carcinoma patient (n=32) sera, did not induce RBL SX-38 cell degranulation. Exposure to FRα-expressing ovarian tumour cells at target-to-effector ratios expected within tumours induced degranulation. MOv18 IgE did not induce expression of CD63 in blood basophils from either healthy volunteers (n=6), or cancer patients, despite detectable levels of circulating FRα (n=5). CONCLUSION AND CLINICAL RELEVANCE These encouraging data are compatible with the hypothesis that, when ovarian carcinoma patients are treated with MOv18, FcɛRI-mediated activation of effector cells occurs within the tumour mass but not in the circulation mandating, with due caution, further pre-clinical studies.
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MESH Headings
- Animals
- Antibodies, Monoclonal, Murine-Derived/adverse effects
- Antibodies, Monoclonal, Murine-Derived/genetics
- Antibodies, Monoclonal, Murine-Derived/immunology
- Antibody Specificity
- Antigens, Neoplasm/immunology
- Basophils/immunology
- Carcinoma/immunology
- Carcinoma/therapy
- Cell Degranulation
- Cell Line, Tumor
- Female
- Folate Receptor 1/blood
- Folate Receptor 1/immunology
- Folate Receptor 1/metabolism
- Humans
- Hypersensitivity, Immediate/etiology
- Hypersensitivity, Immediate/immunology
- Immunoglobulin E/genetics
- Immunoglobulin E/immunology
- Ovarian Neoplasms/immunology
- Ovarian Neoplasms/therapy
- Protein Engineering
- Rats
- Receptors, IgE/immunology
- Tetraspanin 30/metabolism
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Affiliation(s)
- S M Rudman
- NIHR Biomedical Research Centre at Guy's and St Thomas's Hospitals and King's College London, Cutaneous Medicine & Immunotherapy Unit, St John's Institute of Dermatology, Division of Genetics & Molecular Medicine, King's College London School of Medicine, Guy's Hospital, King's College London, London, UK
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29
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Shamji MH, James LK, Durham SR. Serum immunologic markers for monitoring allergen-specific immunotherapy. Immunol Allergy Clin North Am 2011; 31:311-23, x. [PMID: 21530822 DOI: 10.1016/j.iac.2011.03.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Allergen immunotherapy is an effective treatment option in patients with IgE-mediated allergy, particularly in those who do not respond to usual antiallergic drugs. Successful immunotherapy has been associated with the suppression of allergic inflammation in target organs and increases in allergen-specific IgG antibodies, particularly the IgG(4) subclass. To date there are no biomarkers that are predictive of the clinical response to immunotherapy. This article explores the possibility that functional assays based on the ability of IgG to compete with IgE and inhibit IgE-allergen complex formation may be surrogate or predictive of the clinical response to immunotherapy.
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Affiliation(s)
- Mohamed H Shamji
- Allergy and Clinical Immunology Section, National Heart and Lung Institute, Medical Research Council and Asthma UK Centre for Allergic Mechanisms of Asthma, Imperial College London, Dovehouse Street, London, SW3 6LY, UK.
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CD23b isoform expression in human schistosomiasis identifies a novel subset of activated B cells. Infect Immun 2011; 79:3770-7. [PMID: 21708991 DOI: 10.1128/iai.05094-11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Resistance to schistosomiasis is associated with increased levels of serum parasite-specific IgE. IgE exerts its functions through its cellular receptors, FcεRI and FcεRII/CD23; however, its functional significance in humans requires further characterization. We previously reported that increased levels of CD23(+) B cells correlate with resistance to schistosomiasis in hyperexposed populations and sought to define their potential function and relationship with IgE. We found that CD23(+) B cells are a heterogeneous cell population with functional and phenotypic differences. Circulating CD23(+) B cells are uniquely activated in schistosomiasis and express the CD23b isoform and CXCR5, the homing receptor for lymphoid follicles. High CXCR5 expression by CD23(+) B cells was associated with the capacity to home to the cognate ligand CXCL13. CD23-bound IgE cross-linking increased surface expression of CXCR5, suggesting that CD23(+) B cells home directly into the lymphoid follicles upon antigen capture. As human schistosomiasis is an intravascular parasitic infection associated with a high antigenic burden in the blood, circulating CD23(+) B cells may play a role in the capture and shuttling of antigens directly to splenic follicles, highlighting a new role for circulating B cells. This function likely plays an important role in the development of protective immunity to infection with schistosomes.
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Griffith QK, Liang Y, Onguru DO, Mwinzi PN, Ganley-Leal LM. CD23-bound IgE augments and dominates recall responses through human naive B cells. THE JOURNAL OF IMMUNOLOGY 2010; 186:1060-7. [PMID: 21160045 DOI: 10.4049/jimmunol.1002709] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Human peripheral blood BCRμ(+) B cells express high levels of CD23 and circulate preloaded with IgE. The Ag specificity of CD23-bound IgE presumably differs from the BCR and likely reflects the Ag-specific mix of free serum IgE. CD23-bound IgE is thought to enhance B cell Ag presentation to T cells raising the question of how a B cell might respond when presented with a broad mix of Ags and CD23-bound IgE specificities. We recently reported that an increase in CD23(+) B cells is associated with the development of resistance to schistosomiasis, highlighting the potential importance of CD23-bound IgE in mediating immunity. We sought to determine the relationship between BCR and CD23-bound IgE-mediated B cell activation in the context of schistosomiasis. We found that crude schistosome Ags downregulate basal B cell activation levels in individuals hyperexposed to infectious worms. Schistosome-specific IgE from resistant, occupationally exposed Kenyans recovered responses of B cells to schistosome Ag. Furthermore, cross-linking of CD23 overrode intracellular signals mediated via the BCR, illustrating its critical and dominating role in B cell activation. These results suggest that CD23-bound IgE augments and dominates recall responses through naive B cells.
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Affiliation(s)
- Qyana K Griffith
- Section of Infectious Diseases, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, MA 02118, USA
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Acharya M, Borland G, Edkins AL, Maclellan LM, Matheson J, Ozanne BW, Cushley W. CD23/FcεRII: molecular multi-tasking. Clin Exp Immunol 2010; 162:12-23. [PMID: 20831712 DOI: 10.1111/j.1365-2249.2010.04210.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
CD23 is the low-affinity receptor for immunoglobulin (Ig)E and plays important roles in the regulation of IgE responses. CD23 can be cleaved from cell surfaces to yield a range of soluble CD23 (sCD23) proteins that have pleiotropic cytokine-like activities. The regions of CD23 responsible for interaction with many of its known ligands, including IgE, CD21, major histocompatibility complex (MHC) class II and integrins, have been identified and help to explain the structure-function relationships within the CD23 protein. Translational studies of CD23 underline its credibility as a target for therapeutic intervention strategies and illustrate its involvement in mediating therapeutic effects of antibodies directed at other targets.
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Affiliation(s)
- M Acharya
- Division of Molecular and Cellular Biology, Faculty of Biomedical and Life Sciences, University of Glasgow, CR-UK Beatson Institute, Glasgow, UK
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Mathews JA, Gibb DR, Chen BH, Scherle P, Conrad DH. CD23 Sheddase A disintegrin and metalloproteinase 10 (ADAM10) is also required for CD23 sorting into B cell-derived exosomes. J Biol Chem 2010; 285:37531-41. [PMID: 20876574 DOI: 10.1074/jbc.m110.141556] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The low affinity receptor for IgE, CD23, is the natural regulator of IgE synthesis, and understanding both the synthesis and the catabolism of CD23 are, thus, important issues. Membrane CD23 is cleaved by a disintegrin and metalloproteinase 10 (ADAM10) and this cleavage influences the ability of CD23 to regulate IgE. In contrast to the belief that cleavage is a cell surface event, endosomal neutralization with NH(4)Cl was found to dramatically reduce CD23 cleavage, suggesting that the majority of CD23 cleavage occurred subsequent to internalization in the endosomal pathway and not at the cell surface. In line with this, full-length CD23 was shown to be sorted in an ADAM10-dependent manner into exosomes. Greatly increased ADAM10-mediated CD23 cleavage was seen at endosomal pH. Additionally, the stalk region of CD23 was found to interact with ADAM10 and ADAM10 binding of CD23 was found to be protease independent. SPR analysis of the interaction indicated about a 10-fold increase in the R(max) at endosomal pH (pH 5.8) compared with pH 7.4, whereas the affinity of the interaction was not significantly changed. The R(max) change, combined with the increased cleavage at endosomal pH, indicates greater accessibility of the CD23 stalk region for ADAM10 at the lower pH. These results indicate a model where CD23 internalization results in ADAM10-dependent incorporation into exosomes, followed by partial cleavage of CD23 by ADAM10 prior to being released from the cell. The increased cleavage at endosomal pH also has implications for other ADAM10 substrates.
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Affiliation(s)
- Joel A Mathews
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, USA
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Cheng LE, Wang ZE, Locksley RM. Murine B cells regulate serum IgE levels in a CD23-dependent manner. THE JOURNAL OF IMMUNOLOGY 2010; 185:5040-7. [PMID: 20870945 DOI: 10.4049/jimmunol.1001900] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The manifestations of allergic disorders are closely tied to the biologic effects of IgE activation with Ag. In immediate hypersensitivity reactions, IgE effector function requires prior binding to innate immune cells, primarily mast cells and basophils, with the blood acting as a reservoir for unbound IgE. As the severity of allergic disease is proportional to the size of this unbound IgE pool, we hypothesized that cellular mechanisms exist to limit the size and/or enhance the clearance of free IgE molecules. We examined this in mice by engineering a reporter IgE molecule that allowed us to track the fate of IgE molecules in vivo. The absence of FcεRI-expressing cells did not affect serum IgE levels, but B cells regulated serum IgE by controlling the size of the free IgE pool. B cells captured IgE by direct binding to the low-affinity IgE receptor, CD23. These data indicate a mechanism regulating serum IgE and additionally clarify the role of CD23 in this process.
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Affiliation(s)
- Laurence E Cheng
- Department of Pediatrics, University of California, San Francisco, San Francisco, CA 94143, USA
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Buc M, Dzurilla M, Vrlik M, Bucova M. Immunopathogenesis of bronchial asthma. Arch Immunol Ther Exp (Warsz) 2009; 57:331-44. [PMID: 19688187 DOI: 10.1007/s00005-009-0039-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 04/16/2009] [Indexed: 12/27/2022]
Abstract
Bronchial asthma is a common immune-mediated disorder characterized by reversible airway inflammation, mucus production, and variable airflow obstruction with airway hyperresponsiveness. Allergen exposure results in the activation of numerous cells of the immune system, of which dendritic cells (DCs) and Th2 lymphocytes are of paramount importance. Although the epithelium was initially considered to function solely as a physical barrier, it is now evident that it plays a central role in the Th2-cell sensitization process due to its ability to activate DCs. Cytokines are inevitable factors in driving immune responses. To the list of numerous cytokines already known to be involved in the regulation of allergic reactions, new cytokines were added, such as TSLP, IL-25, and IL-33. IgE is also a central player in the allergic response. The activity of IgE is associated with a network of proteins, especially with its high- and low-affinity Fc receptors. Understanding the cellular and molecular mechanisms of allergic reactions helps us not only to understand the mechanisms of current treatments, but is also important for the identification of new targets for biological intervention. An IgE-specific monoclonal antibody, omalizumab, has already reached the clinic and similar biological agents will surely follow.
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Affiliation(s)
- Milan Buc
- Department of Immunology, Comenius University School of Medicine, Bratislava, Slovakia.
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Abstract
BACKGROUND A proteinase with a disintegrin and a metalloproteinase domain-8 (ADAM8) has been linked to asthma. OBJECTIVE To explore whether ADAM8 is a therapeutic target for asthma. METHODS We reviewed literature on ADAM8's function and expression and activities in lungs of humans and mice with allergic airway inflammation (AAI). We used these data to generate hypotheses about the contributions of ADAM8 to asthma pathogenesis. CONCLUSIONS ADAM8 levels are increased in airway epithelium and airway inflammatory cells in mice with AAI and human asthma patients. Data from murine models of AAI indicate that ADAM8 dampens airway inflammation. It is not clear whether ADAM8 contributes directly to structural remodeling in asthmatic airways. Additional studies are required to validate ADAM8 as a therapeutic target for asthma.
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Affiliation(s)
- Martin D Knolle
- Brigham and Women's Hospital, Harvard Medical School, Division of Pulmonary and Critical Care Medicine, 905 Thorn Building, 75 Francis Street, Boston, MA 02115, USA
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Schwarzmeier JD, Hubmann R, Düchler M, Jäger U, Shehata M. Regulation of CD23 expression by Notch2 in B-cell chronic lymphocytic leukemia. Leuk Lymphoma 2009; 46:157-65. [PMID: 15621797 DOI: 10.1080/10428190400010742] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The original observation that sera from patients with chronic B-cell lymphocytic leukemia (B-CLL) contain high amounts of soluble CD23 (sCD23), which reflect disease activity and tumor load has been confirmed by numerous reports and serial determinations of sCD23 are now recognized as important indicators of disease progression. The reason why the leukemic cells over express CD23 and subsequently release large quantities of sCD23 as compared to healthy persons or patients with other lymphoproliferative disorders is still not clear. However, progress has been made in understanding the mechanism leading to the upregulation of CD23 in the leukemic cells. Following is an update on clinical data and a short review on the potential functions of CD23 as well as its regulation by Notch2 in B-CLL.
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MESH Headings
- Cell Lineage
- Gene Expression Regulation
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/immunology
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- Receptor, Notch2
- Receptors, Cell Surface/physiology
- Receptors, IgE/blood
- Receptors, IgE/genetics
- Receptors, IgE/physiology
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Affiliation(s)
- J D Schwarzmeier
- Medical University of Vienna, Clinic of Internal Med. I, Division of Hematology, Waehringer Guertel, Austria.
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Wolfram C, Rasche C, Audring H, Wahls M, Worm M. Isolation and phenotypic characterization of mucosal nasal lymphocytes by direct ex vivo analysis. Eur Arch Otorhinolaryngol 2008; 266:677-83. [PMID: 18766360 DOI: 10.1007/s00405-008-0795-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Accepted: 08/11/2008] [Indexed: 11/30/2022]
Abstract
Cellular inflammation of the nasal mucosa demonstrates a local immune response which plays an important role in allergic rhinitis. The aim of the present study was to characterize nasal mucosal lymphocytes regarding their activation and differentiation state by direct ex vivo flowcytometric analysis. Lymphocytes from the inferior turbinates were isolated by a mechanical method of preparation and, for comparison, from peripheral blood by Ficoll gradient centrifugation. Patients suffering from rhinitis or difficulty in nasal breathing were divided into an allergic (pollen-allergy, n = 13) and non-allergic group (n = 24). Expression of different T- and B-cell markers was determined by flowcytometric analysis. CD4+ T-cells from the nasal mucosa exhibited a memory phenotype (CD45RO+, 97%), were highly activated (CD69+, 43-73%), and showed low expression of the cutaneous lymphocyte antigen (CLA+, 5%). Nasal CD20+ B-lymphocytes expressed significantly higher levels of mIgE and lower levels of CD23 and CD80 than peripheral B-cells. Subsets of CD80+ (4%) and CD86+ (6%) CD20+ B-lymphocytes were identified in the nasal mucosa. No significant differences between allergic and non-allergic individuals were determined. As expected, the data show profound phenotypical differences between circulating peripheral blood and nasal mucosal lymphocytes. Activated memory lymphocytes are present in the nasal mucosa from allergic, but also non-allergic patients and may indicate to a significant role of a local inflammatory state without systemic criteria for allergy. In our study, we show that direct ex vivo isolation of lymphocytes is practicable method and offers a new technique to examine the local nasal allergic immune response using a multiparametric phenotypical analysis.
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Affiliation(s)
- Christin Wolfram
- Department of Dermatology and Allergy, Allergy-Center-Charité, Medical University Berlin, Campus Charité Mitte, Charitéplatz 1, 10117, Berlin, Germany
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Hjelm F, Karlsson MCI, Heyman B. A Novel B Cell-Mediated Transport of IgE-Immune Complexes to the Follicle of the Spleen. THE JOURNAL OF IMMUNOLOGY 2008; 180:6604-10. [DOI: 10.4049/jimmunol.180.10.6604] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Abstract
The spreading epidemic of allergies and asthma has heightened interest in IgE, the central player in the allergic response. The activity of IgE is associated with a network of proteins; prominent among these are its two principal receptors, FcepsilonRI (high-affinity Fc receptor for IgE) and CD23, as well as galectin-3 and several co-receptors for CD23, notably CD21 and various integrins. Here, we review recent progress in uncovering the structures of these proteins and their complexes, and in our understanding of how IgE exerts its effects and how its expression is regulated. The information that has emerged suggests new therapeutic directions for combating allergic disease.
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Meng JF, McFall C, Rosenwasser LJ. Polymorphism R62W results in resistance of CD23 to enzymatic cleavage in cultured cells. Genes Immun 2007; 8:215-23. [PMID: 17301828 DOI: 10.1038/sj.gene.6364376] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A nonsynonymous single nucleotide polymorphism (SNP) of the low-affinity IgE receptor (FcvarepsilonRII/CD23) gene resulting in an arginine to tryptophan exchange at amino-acid position 62 (R62W) has been associated with enhanced T-cell responses to antigen in allergic subjects. To explore the mechanism, a CD23(a) cDNA was cloned into the plasmid pCMVScript-CD23a-C with a C allele (R62). The pCMVScript-CD23a-T with T (W62) was produced using a site-directed mutagenesis approach. The pCMVScript-CD23a-C only (CC), mixture of pCMVScript-CD23a-T and pCMVSCript-CD23a-C (CT) and pCMVScript-CD23a-T only (TT) plasmids were transfected in Cos-7 cells at equivalence in transfection efficiency. No soluble CD23 was released from TT transfectants whereas a higher level of soluble CD23 was detected in CC than in CT transfectants. Human leukocyte elastase (HLE), cathepsin G, the dust mite allergen Der p I and ADAM 33 (A disintegrin and metalloproteinase) were found to cleave membrane CD23 in CC but not in TT transfectants, implying the resistance of CD23 to enzymatic cleavage associated with T mutant. Addition of tunicamycin resulted in the resistance of CD23 to Der p I mediated cleavage in CC but no change in TT transfectants. These results indicate that R62W influences the stability of membrane CD23 molecules due to possibly diminished N-glycosylation.
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Affiliation(s)
- J-F Meng
- 1Pediatric Immunology Research Department, Children's Mercy Hospital/School of Medicine, University of Missouri at Kansas City, Kansas City, MO, USA.
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Konforte D, Paige CJ. Identification of cellular intermediates and molecular pathways induced by IL-21 in human B cells. THE JOURNAL OF IMMUNOLOGY 2007; 177:8381-92. [PMID: 17142735 DOI: 10.4049/jimmunol.177.12.8381] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The complex process of B cell development is controlled by multiple factors from the surrounding microenvironment including cytokines. IL-21 is a recently identified type I cytokine, mainly produced by activated CD4(+) T cells. It has been shown to promote differentiation of human primary B cells into Ig-secreting plasma cells. The objective of our study was to describe cellular intermediates that exist during IL-21-induced transition from an activated B cell to an Ig-secreting cell and to identify molecular mechanisms involved in this process. Novel Epstein-Barr Virus-positive human B cell lines with phenotypes characteristic of Ag-activated IgG(+) B cell blasts were used as a model system to study IL-21 effects in vitro. We show that IL-21 increased both proliferation and survival of B cell lines during the first 3 days of in vitro culture. This process was associated with CD38(low/int)CD23(int)HLA-DR(high)CD19(high)CD20(int) cell surface phenotype. Continued culture with IL-21 resulted in accumulation of cells in G(0)/G(1) stage of the cell cycle and increased apoptosis. This coincided with differentiation into small, CD38(high)CD23(low/-)HLA-DR(int)CD19(int)CD20(low) late plasmablasts/early plasma cells that expressed lower levels of c-Myc protein, and secreted greater amounts of Ig than the control cells. Partial inhibition of IL-21-induced JAK/STAT signaling by the low-dose pharmacological agent, JAK inhibitor I, did not prevent the initial increase in proliferation. However, decrease in c-Myc protein expression and subsequent differentiation to late plasmablasts/early plasma cells were strongly inhibited. Our study is the first to show the link between IL-21-induced JAK/STAT signaling, c-Myc regulation, and differentiation of human B cells.
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Affiliation(s)
- Danijela Konforte
- Division of Stem Cell and Developmental Biology, Princess Margaret Hospital, Ontario Cancer Institute, University Health Network, 610 University Avenue, Toronto, Ontario, Canada.
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Wurzburg BA, Tarchevskaya SS, Jardetzky TS. Structural changes in the lectin domain of CD23, the low-affinity IgE receptor, upon calcium binding. Structure 2006; 14:1049-58. [PMID: 16765898 DOI: 10.1016/j.str.2006.03.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Revised: 03/03/2006] [Accepted: 03/27/2006] [Indexed: 11/28/2022]
Abstract
CD23, the low-affinity receptor for IgE (Fc epsilonRII), regulates IgE synthesis and also mediates IgE-dependent antigen transport and processing. CD23 is a unique Fc receptor belonging to the C-type lectin-like domain superfamily and binds IgE in an unusual, non-lectin-like manner, requiring calcium but not carbohydrate. We have solved the high-resolution crystal structures of the human CD23 lectin domain in the presence and absence of Ca2+. The crystal structures differ significantly from a previously determined NMR structure and show that calcium binding occurs at the principal binding site, but not at an auxiliary site that appears to be absent in human CD23. Conformational differences between the apo and Ca2+ bound structures suggest how IgE-Fc binding can be both calcium-dependent and carbohydrate-independent.
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Affiliation(s)
- Beth A Wurzburg
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208, USA
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Wilcock LK, Francis JN, Durham SR. IgE-Facilitated Antigen Presentation: Role in Allergy and the Influence of Allergen Immunotherapy. Immunol Allergy Clin North Am 2006; 26:333-47, viii-ix. [PMID: 16701148 DOI: 10.1016/j.iac.2006.02.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
IgE-facilitated allergen presentation (FAP) is an important pathogenic mechanism in allergic disease and represents a potential therapeutic target. Allergen immunotherapy is a highly effective therapy, particularly in patients with seasonal pollinosis who fail to respond to usual pharmacotherapy. Allergen immunotherapy induces "blocking" IgG antibodies that are detectable in serum and have been shown to inhibit IgE-FAP in vitro. This review summarizes the main components involved in IgE-FAP and the potential value of a validated functional assay of serum inhibitory antibodies for IgE-FAP for monitoring the clinical response to immunotherapy.
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Affiliation(s)
- Louisa K Wilcock
- Upper Respiratory Medicine, Imperial College, National Heart and Lung Institute, Dovehouse Street, London SW3 6LY, UK
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Mansour MK, Latz E, Levitz SM. Cryptococcus neoformans glycoantigens are captured by multiple lectin receptors and presented by dendritic cells. THE JOURNAL OF IMMUNOLOGY 2006; 176:3053-61. [PMID: 16493064 DOI: 10.4049/jimmunol.176.5.3053] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cell-mediated immune responses to glycoantigens have been largely uncharacterized. Protective T cell responses to the pathogenic yeast Cryptococcus neoformans are dependent on heavily mannosylated Ags termed mannoproteins. In the work presented, the innate immune response to mannoprotein was determined. Purified murine splenic dendritic cells (DC), B cells, and macrophages were used to stimulate mannoprotein-specific T cells. Only DC were capable of any measurable stimulation. Depletion of DC resulted in the abrogation of the T cell response. Human and murine DC rapidly captured fluorescent-labeled mannoprotein by a mannose receptor-mediated process. Using transfected cell lines, the type II C-type lectin receptor DC-specific ICAM-3-grabbing nonintegrin (CD209) was determined to have affinity for mannoprotein. Taken together with prior work demonstrating that mannoprotein was captured by the macrophage mannose receptor (CD206), these data suggest that multiple mannose receptors on DC recognize mannoprotein. Pulsing experiments demonstrated that DC captured sufficient mannoprotein over 2 h to account for 50% of total stimulation. Capture appeared dependent on mannose receptors, as competitive mannosylated inhibitors and calcium chelators each interfered with T cell stimulation. By confocal microscopy, intracellular mannoprotein trafficked to an endo-lysosomal compartment in DC, and at later time points extended into tubules in a similar fashion to the degradation marker DQ-OVA. Mannoprotein colocalized intracellularly with CD206 and CD209. These data suggest that DC provide the crucial link between innate and adaptive immune responses to C. neoformans via a process that is dependent upon the efficient uptake of mannoprotein by mannose receptors.
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Affiliation(s)
- Michael K Mansour
- Department of Microbiology and Immunology Training Program, Boston University School of Medicine, Boston, MA 02118, USA
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46
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Abstract
CD23, the low-affinity immunoglobulin (Ig)E receptor (FcepsilonRII), is widely distributed on the surface of various human cells. CD23 mediates numerous IgE-related immune responses (including allergen focusing) by enhancing IgE antigen complex presentation, regulating IgE synthesis, influencing cell differentiation and growth of both B- and T-cells, and stimulating production of pro-inflammatory mediators from monocytes/macrophages, eosinophils, and even airway smooth muscle cells. Both membrane and soluble CD23 play an important role in allergic reactions. Cellular contacts and cytokines modulate its expression in a concerted manner as needed for allergic reactions. Expression of CD23 and soluble CD23 has been associated with allergic diseases. Targeting CD23 with monoclonal antibody (MAb) is a promising candidate therapy in allergic diseases. A newly developed agent known as Lumiliximab, which is an anti-CD23 MAb (Lumiliximab), was demonstrated to be a well-tolerated agent in a phase I clinical trial (a placebo-controlled study with allergic asthma). Adverse events were mild, and no relationship was apparent between the dose of Lumilixilab and the frequency, severity, or type of event. Sustained and dose-dependent decreases in mean serum total IgE concentrations were noted. The serum half-life of Lumilixilab increased from 2 to 10 d with increasing doses. Blocking antigen presentation, preventing costimulation signals, and reducing production of pro-inflammatory mediators are some of the potential mechanisms involved for anti-CD23 activity. Although the safety and clinical efficacy of Lumilixilab in allergic asthma and rhinitis require confirmation, the observed data imply that anti-CD23 is a promising candidate therapy option for future treatment of allergic diseases.
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Affiliation(s)
- Lanny J Rosenwasser
- Division of Allergy and Immunology, Department of Medicine, National Jewish Medical and Research Center/University of Colorado Health Sciences Center, Denver, CO, USA.
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Poole JA, Meng J, Reff M, Spellman MC, Rosenwasser LJ. Anti-CD23 monoclonal antibody, lumiliximab, inhibited allergen-induced responses in antigen-presenting cells and T cells from atopic subjects. J Allergy Clin Immunol 2005; 116:780-8. [PMID: 16210051 DOI: 10.1016/j.jaci.2005.07.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2005] [Revised: 06/08/2005] [Accepted: 07/12/2005] [Indexed: 11/19/2022]
Abstract
BACKGROUND CD23 plays a role in the regulation of IgE production and allergy-induced immune and inflammatory responses. A novel anti-CD23 monoclonal antibody, lumiliximab, is a potential therapeutic antibody recently demonstrated to be safe in human beings. OBJECTIVE This study investigated the effects of lumiliximab on allergen-induced immune responses from atopic subjects compared with blocking HLA-DR and costimulatory molecules, CD80 and CD86. METHODS Allergen-stimulated PBMCs from atopic subjects were pretreated with lumiliximab or antibodies to CD80, CD86, and HLA-DR. Cultures were analyzed for cell proliferation and IL-1beta, TNF-alpha, and IL-5 cytokine secretion. An allergen-specific T-cell line was developed and analyzed for lymphocyte proliferation in response to allergen with or without lumiliximab. Lumiliximab's effect on CD86 expression was evaluated by flow cytometry in the U937 monocytic cell line. RESULTS Lumiliximab reduced allergen-induced PBMC proliferation by 50% (n = 6; P = .006). In addition, cultures pretreated with lumiliximab had a reduction in the proinflammatory cytokines IL-1beta (P < .003) and TNF-alpha (P = .05) and the T(H)2 cytokine IL-5 (P = .002). Blocking CD86 resulted in greater reduction in proliferation than lumiliximab (P = .003) but similar effects in cytokine secretion. The anti-CD80 blocking antibody had no effect on cytokine production but did reduce proliferation. Furthermore, the addition of lumiliximab to cytokine stimulated U937 cells reduced surface expression of CD86 (P = .012). CONCLUSION These results indicate that the anti-CD23 mAb, lumiliximab, may be involved in modulating antigen presenting cells and reducing TH2-type immune responses. The use of this antibody may provide clinical benefit for treating allergic diseases.
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Affiliation(s)
- Jill A Poole
- National Jewish Medical and Research Center, University of Colorado Health Sciences Center, Division of Allergy and Clinical Immunology, Department of Medicine, Denver, USA.
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Poole JA, Rosenwasser LJ. The role of immunoglobulin E and immune inflammation: implications in allergic rhinitis. Curr Allergy Asthma Rep 2005; 5:252-8. [PMID: 15842964 DOI: 10.1007/s11882-005-0045-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Immunoglobulin E (IgE) plays a critical role in the allergic inflammatory process in diseases such as allergic rhinitis. Cross-linking IgE bound to its receptor on cells by multivalent allergens initiates a chain of events resulting in allergic immune responses. Mast cells and basophils are involved in the early, immediate response, which is marked by cellular degranulation and the release of proinflammatory mediators, including histamine. Antigen-presenting cells are also activated by allergen-loaded IgE, resulting in immunomodulation of T-cell responses. The IgE molecule binds to two types of receptors, the high-affinity (Fc epsilonRI) and low-affinity (Fc epsilonRII or CD23) receptors, that have differing properties important in mediating allergen-induced responses. New therapies targeting the IgE molecule reduce allergen-stimulated immune responses and improve the clinical symptoms in subjects with allergic rhinitis. Understanding the role of the IgE molecule is necessary to appreciate the development and use of novel therapies targeting its actions.
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MESH Headings
- Antibodies, Anti-Idiotypic
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Monoclonal, Humanized
- Antigen-Presenting Cells/immunology
- Antigen-Presenting Cells/metabolism
- Clinical Trials as Topic
- Humans
- Immunoglobulin E/immunology
- Immunoglobulin E/metabolism
- Inflammation/immunology
- Omalizumab
- Receptors, IgE/immunology
- Receptors, IgE/metabolism
- Rhinitis, Allergic, Perennial/drug therapy
- Rhinitis, Allergic, Perennial/immunology
- Rhinitis, Allergic, Seasonal/drug therapy
- Rhinitis, Allergic, Seasonal/immunology
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Affiliation(s)
- Jill A Poole
- National Jewish Medical and Research Center, University of Colorado Health Sciences Center, Denver 80206, USA
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Tu Y, Salim S, Bourgeois J, Di Leo V, Irvine EJ, Marshall JK, Perdue MH. CD23-mediated IgE transport across human intestinal epithelium: inhibition by blocking sites of translation or binding. Gastroenterology 2005; 129:928-40. [PMID: 16143132 DOI: 10.1053/j.gastro.2005.06.014] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Accepted: 05/26/2005] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS In previous studies in rodent models of food allergy, we identified that sensitization induces expression of CD23 on intestinal epithelial cells and results in enhanced IgE-dependent transepithelial antigen uptake; further studies in CD23-/- mice provided evidence that CD23 is involved in protected transport of antigen into the body. Little information exists in humans on receptor-mediated immunoglobulin (Ig)E transport across epithelia. The present study was designed to examine expression of CD23 by human epithelial cells, determine its isoform and regulation by interleukin (IL) 4, and identify the role of CD23 in transepithelial IgE transport. METHODS Epithelial expression of CD23 was studied in cell lines, ileal biopsy specimens, and explanted fetal intestine. Bidirectional transport of IgE was measured across filter-grown cells, either normal cells or those transfected with antisense CD23 oligonucleotides, or in the presence of blocking antibody. RESULTS Expression of the low-affinity IgE receptor was demonstrated in cultured epithelial cells as well as in situ cells in human intestine. CD23b was the isoform expressed by HT29, T84, and Caco-2 cells. IL-4 up-regulated the expression of epithelial CD23. IgE was transported in both the basal-to-apical direction and the apical-to-basal direction across filter-grown epithelial cells, a process that was inhibited by transfection of cells with CD23 antisense oligonucleotides or pretreatment with nonspecific IgE or anti-CD23 antibody. CONCLUSIONS These findings provide evidence that CD23 encodes a functional IgE receptor on human intestinal epithelial cells and that this epithelial receptor is likely to play an important role in food allergies.
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Affiliation(s)
- Yahong Tu
- Intestinal Disease Research Program, McMaster University, Hamilton, Ontario, Canada
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Getahun A, Hjelm F, Heyman B. IgE Enhances Antibody and T Cell Responses In Vivo via CD23+ B Cells. THE JOURNAL OF IMMUNOLOGY 2005; 175:1473-82. [PMID: 16034084 DOI: 10.4049/jimmunol.175.3.1473] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
IgE Abs, passively administered together with their specific Ag, can enhance the production of Abs recognizing this Ag by >100-fold. IgE-mediated feedback enhancement requires the low affinity receptor for IgE, CD23. One possible mechanism is that B cells take up IgE-Ag via CD23 and efficiently present Ag to Th cells, resulting in better Ab responses. To test whether IgE Abs have an effect on Th cells in vivo, mice were adoptively transferred with CD4+ T cells expressing a transgenic OVA-specific TCR, before immunization with IgE anti-TNP (2,4,6-trinitrophenyl) plus OVA-TNP or with OVA-TNP alone. IgE induced a 6- to 21-fold increase in the number of OVA-specific T cells. These cells acquired an activated phenotype and were visible in splenic T cell zones. The T cell response peaked 3 days after immunization and preceded the OVA-specific Ab response by a few days. Transfer of CD23+ B cells to CD23-deficient mice rescued their ability to respond to IgE-Ag. Interestingly, in this situation also CD23-negative B cells produce enhanced levels of OVA-specific Abs. The data are compatible with the Ag presentation model and suggest that B cells can take up Ag via "unspecific" receptors and activate naive T cells in vivo.
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MESH Headings
- Adjuvants, Immunologic/administration & dosage
- Adjuvants, Immunologic/physiology
- Animals
- Antibody Formation/genetics
- Antigen Presentation/genetics
- Antigen-Antibody Complex/administration & dosage
- Antigen-Antibody Complex/physiology
- B-Lymphocyte Subsets/immunology
- B-Lymphocyte Subsets/metabolism
- B-Lymphocyte Subsets/transplantation
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- CD4-Positive T-Lymphocytes/transplantation
- Epitopes, T-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/metabolism
- Haptens/administration & dosage
- Haptens/immunology
- Immunoglobulin E/administration & dosage
- Immunoglobulin E/metabolism
- Immunoglobulin E/physiology
- Lymphocyte Activation/genetics
- Lymphocyte Activation/immunology
- Mice
- Mice, Congenic
- Mice, Inbred BALB C
- Mice, Transgenic
- Ovalbumin/administration & dosage
- Ovalbumin/immunology
- Receptors, IgE/biosynthesis
- Receptors, IgE/deficiency
- Receptors, IgE/genetics
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- Trinitrobenzenes/administration & dosage
- Trinitrobenzenes/immunology
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Affiliation(s)
- Andrew Getahun
- Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
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