51
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Burton OT, Epp A, Fanny ME, Miller SJ, Stranks AJ, Teague JE, Clark RA, van de Rijn M, Oettgen HC. Tissue-Specific Expression of the Low-Affinity IgG Receptor, FcγRIIb, on Human Mast Cells. Front Immunol 2018; 9:1244. [PMID: 29928276 PMCID: PMC5997819 DOI: 10.3389/fimmu.2018.01244] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 05/17/2018] [Indexed: 11/13/2022] Open
Abstract
Immediate hypersensitivity reactions are induced by the interaction of allergens with specific IgE antibodies bound via FcεRI to mast cells and basophils. While these specific IgE antibodies are needed to trigger such reactions, not all individuals harboring IgE exhibit symptoms of allergy. The lack of responsiveness seen in some subjects correlates with the presence of IgG antibodies of the same specificity. In cell culture studies and in vivo animal models of food allergy and anaphylaxis such IgG antibodies have been shown to exert suppression via FcγRIIb. However, the reported absence of this inhibitory receptor on primary mast cells derived from human skin has raised questions about the role of IgG-mediated inhibition of immediate hypersensitivity in human subjects. Here, we tested the hypothesis that mast cell FcγRIIb expression might be tissue specific. Utilizing a combination of flow cytometry, quantitative PCR, and immunofluorescence staining of mast cells derived from the tissues of humanized mice, human skin, or in fixed paraffin-embedded sections of human tissues, we confirm that FcγRIIb is absent from dermal mast cells but is expressed by mast cells throughout the gastrointestinal tract. IgE-induced systemic anaphylaxis in humanized mice is strongly inhibited by antigen-specific IgG. These findings support the concept that IgG, signaling via FcγRIIb, plays a physiological role in suppressing hypersensitivity reactions.
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Affiliation(s)
- Oliver T Burton
- Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
| | - Alexandra Epp
- Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
| | - Manoussa E Fanny
- Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
| | - Samuel J Miller
- Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
| | - Amanda J Stranks
- Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
| | - Jessica E Teague
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Rachael A Clark
- Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Matt van de Rijn
- Department of Pathology, Stanford University Medical Center, Palo Alto, CA, United States
| | - Hans C Oettgen
- Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
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52
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Zakeri A, Russo M. Dual Role of Toll-like Receptors in Human and Experimental Asthma Models. Front Immunol 2018; 9:1027. [PMID: 29867994 PMCID: PMC5963123 DOI: 10.3389/fimmu.2018.01027] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 04/24/2018] [Indexed: 12/31/2022] Open
Abstract
Asthma is a chronic airway inflammatory disease that is influenced by the interplay between genetic factors and exposure to environmental allergens, microbes, or microbial products where toll-like receptors (TLRs) play a pivotal role. TLRs recognize a wide range of microbial or endogenous molecules as well as airborne environmental allergens and act as adjuvants that influence positively or negatively allergic sensitization. TLRs are qualitatively and differentially expressed on hematopoietic and non-hematopoietic stromal or structural airway cells that when activated by TLRs agonists exert an immune-modulatory role in asthma development. Therefore, understanding mechanisms and pathways by which TLRs orchestrate asthma outcomes may offer new strategies to control the disease. Here, we aim to review and critically discuss the role of TLRs in human asthma and murine models of allergic airway inflammation, highlighting the complexity of TLRs function in development, exacerbation, or control of airway allergic inflammation.
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Affiliation(s)
- Amin Zakeri
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Infectious Diseases, Aarhus University Hospital, Aarhus, Denmark
| | - Momtchilo Russo
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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53
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Lilienthal GM, Rahmöller J, Petry J, Bartsch YC, Leliavski A, Ehlers M. Potential of Murine IgG1 and Human IgG4 to Inhibit the Classical Complement and Fcγ Receptor Activation Pathways. Front Immunol 2018; 9:958. [PMID: 29867943 PMCID: PMC5954034 DOI: 10.3389/fimmu.2018.00958] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 04/17/2018] [Indexed: 01/07/2023] Open
Abstract
IgG antibodies (Abs) mediate their effector functions through the interaction with Fcγ receptors (FcγRs) and the complement factors. The main IgG-mediated complement activation pathway is induced through the binding of complement C1q to IgG Abs. This interaction is dependent on antigen-dependent hexamer formation of human IgG1 and IgG3 to increase the affinity for the six-headed C1q molecule. By contrast, human IgG4 fails to bind to C1q. Instead, it has been suggested that human IgG4 can block IgG1 and IgG3 hexamerization required for their binding to C1q and activating the complement. Here, we show that murine IgG1, which functionally resembles human IgG4 by not interacting with C1q, inhibits the binding of IgG2a, IgG2b, and IgG3 to C1q in vitro, and suppresses IgG2a-mediated complement activation in a hemolytic assay in an antigen-dependent and IgG subclass-specific manner. From this perspective, we discuss the potential of murine IgG1 and human IgG4 to block the complement activation as well as suppressive effects of sialylated IgG subclass Abs on FcγR-mediated immune cell activation. Accumulating evidence suggests that both mechanisms seem to be responsible for preventing uncontrolled IgG (auto)Ab-induced inflammation in mice and humans. Distinct IgG subclass distributions and functionally opposite IgG Fc glycosylation patterns might explain different outcomes of IgG-mediated immune responses and provide new therapeutic options through the induction, enrichment, or application of antigen-specific sialylated human IgG4 to prevent complement and FcγR activation as well.
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Affiliation(s)
- Gina-Maria Lilienthal
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck and University Medical Center of Schleswig-Holstein, Lübeck, Germany
| | - Johann Rahmöller
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck and University Medical Center of Schleswig-Holstein, Lübeck, Germany.,Department of Anesthesiology and Intensive Care, University of Lübeck and University Medical Center of Schleswig-Holstein, Lübeck, Germany
| | - Janina Petry
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck and University Medical Center of Schleswig-Holstein, Lübeck, Germany
| | - Yannic C Bartsch
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck and University Medical Center of Schleswig-Holstein, Lübeck, Germany
| | - Alexei Leliavski
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck and University Medical Center of Schleswig-Holstein, Lübeck, Germany
| | - Marc Ehlers
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck and University Medical Center of Schleswig-Holstein, Lübeck, Germany.,Airway Research Center North (ARCN), University of Lübeck, German Center for Lung Research (DZL), Lübeck, Germany
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54
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Abstract
Neutrophils play a key role in host defense against pathogens. They can contribute to pathological inflammation, and are thought to exacerbate tissue injury upon exposure to bacterial products, such as endotoxin (LPS). Recent findings suggest that neutrophils can also participate in adaptive immune responses and contribute to inflammation resolution. Many discoveries regarding the in vivo role of neutrophils were made possible by the use of genetically modified neutrophil-deficient mice, or by the use of neutrophil-depleting antibodies. Here we describe a new mouse model, PMNDTR mice, in which neutrophils can be selectively depleted upon injection of diphtheria toxin. Using this model, we have recently demonstrated that neutrophils play a protective role during lethal endotoxin-induced systemic shock. This new mouse model presents several major advantages over more classical models of neutropenia, which are discussed herein.
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Affiliation(s)
- Caitlin M Gillis
- Institut Pasteur, Département d'immunologie, Inserm U1222, Unité des anticorps en thérapie et pathologie, 25, rue du Docteur Roux, 75015 Paris, France
| | - Laurent L Reber
- Institut Pasteur, Département d'immunologie, Inserm U1222, Unité des anticorps en thérapie et pathologie, 25, rue du Docteur Roux, 75015 Paris, France
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55
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Hasegawa A, Watanabe M, Osada H, Ogawa M, Ohno H, Yanuma N, Sasaki K, Shimoda M, Shirai J, Ohmori K. Influence of glucocorticoids on time-of-day-dependent variations in IgE-, histamine-, and platelet-activating factor-mediated systemic anaphylaxis in different mouse strains. Biochem Biophys Res Commun 2018; 495:2184-2188. [PMID: 29269296 DOI: 10.1016/j.bbrc.2017.12.099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 12/18/2017] [Indexed: 10/18/2022]
Abstract
A time-of-day-dependent variation in IgE-mediated passive systemic anaphylaxis was previously reported in ICR mice. In the present study, we investigated time-of-day-dependent variations in IgE-, histamine-, and platelet-activating factor (PAF)-mediated systemic anaphylaxis in C57BL/6, BALB/c, and NC/Nga mice at 9:00 h and 21:00 h, and evaluated the potential influence of glucocorticoids (GCs) on these variations. We found significant time-of-day-dependent variations in IgE-mediated systemic anaphylaxis in C57BL/6 mice, and in histamine- and PAF-mediated systemic anaphylaxis in BALB/c mice. Significant daily variations in IgE-, histamine-, and PAF-mediated systemic anaphylaxis were not observed in NC/Nga mice. Pretreatment with dexamethasone and adrenalectomy abolished the daily variations in IgE-mediated systemic anaphylaxis in C57BL/6 mice and in PAF-mediated systemic anaphylaxis in BALB/c mice, suggesting that GCs from adrenal glands are pivotal in regulating these variations. In contrast, pretreatment with dexamethasone and adrenalectomy did not abolish the daily variation in histamine-mediated systemic anaphylaxis in BALB/c mice, suggesting that GC-independent and adrenal gland-independent mechanisms are important for the variation. The present study demonstrated that time-of-day-dependent variations in systemic anaphylaxis differed among inbred mouse strains and with anaphylaxis-inducing substances. Thus, mouse strains, time of experiment, and anaphylaxis-inducing substances used must be considered to obtain appropriate experimental results.
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Affiliation(s)
- Ayana Hasegawa
- Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Miwa Watanabe
- Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Hironari Osada
- Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Misato Ogawa
- Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Hikaru Ohno
- Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Nanako Yanuma
- Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Kazuaki Sasaki
- Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Minoru Shimoda
- Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Junsuke Shirai
- Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Keitaro Ohmori
- Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan.
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56
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Tong P, Gao L, Gao J, Li X, Wu Z, Yang A, Chen H. Iron-induced chelation alleviates the potential allergenicity of ovotransferrin in a BALB/c mouse model. Nutr Res 2017; 47:81-89. [DOI: 10.1016/j.nutres.2017.09.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 09/27/2017] [Accepted: 09/30/2017] [Indexed: 10/18/2022]
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57
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Muñoz-Cano R, Pascal M, Araujo G, Goikoetxea MJ, Valero AL, Picado C, Bartra J. Mechanisms, Cofactors, and Augmenting Factors Involved in Anaphylaxis. Front Immunol 2017; 8:1193. [PMID: 29018449 PMCID: PMC5623009 DOI: 10.3389/fimmu.2017.01193] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/08/2017] [Indexed: 01/12/2023] Open
Abstract
Anaphylaxis is an acute and life-threatening systemic reaction. Many triggers have been described, including food, drug, and hymenoptera allergens, which are the most frequently involved. The mechanisms described in anaphylactic reactions are complex and implicate a diversity of pathways. Some of these mechanisms may be key to the development of the anaphylactic reaction, while others may only modify its severity. Although specific IgE, mast cells, and basophils are considered the principal players in anaphylaxis, alternative mechanisms have been proposed in non-IgE anaphylactic reactions. Neutrophils, macrophages, as well as basophils, have been involved, as have IgG-dependent, complement and contact system activation. A range of cationic substances can induce antibody-independent mast cells activation through MRGPRX2 receptor. Cofactors and augmenting factors may explain why, in some patients, food allergen exposure can cause anaphylaxis, while in other clinical scenario it can be tolerated or elicits a mild reaction. With the influence of these factors, food allergic reactions may be induced at lower doses of allergen and/or become more severe. Exercise, alcohol, estrogens, and some drugs such as Non-steroidal anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, β-blockers, and lipid-lowering drugs are the main factors described, though their mechanisms and signaling pathways are poorly understood.
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Affiliation(s)
- Rosa Muñoz-Cano
- Unitat d'Allergia, Servei de Pneumologia, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Mariona Pascal
- Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Servei d'Immunologia, Centre de Diagnòstic Biomèdic (CDB), Hospital Clinic, Universitat de Barcelona, Barcelona, Spain
| | - Giovanna Araujo
- Unitat d'Allergia, Servei de Pneumologia, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - M J Goikoetxea
- Allergy and Immunology Department, Universidad de Navarra, Navarra, Spain
| | - Antonio L Valero
- Unitat d'Allergia, Servei de Pneumologia, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Cesar Picado
- Unitat d'Allergia, Servei de Pneumologia, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Joan Bartra
- Unitat d'Allergia, Servei de Pneumologia, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
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58
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Castells M. Diagnosis and management of anaphylaxis in precision medicine. J Allergy Clin Immunol 2017; 140:321-333. [PMID: 28780940 DOI: 10.1016/j.jaci.2017.06.012] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 06/28/2017] [Accepted: 06/29/2017] [Indexed: 12/18/2022]
Abstract
Anaphylaxis is the most severe and frightening of the allergic reactions, placing patients at high risk and demanding prompt recognition and immediate management by health care providers. Yet because its symptoms imitate those of other diseases, such as asthma and urticaria, current data suggest that its diagnosis is often missed, with underuse of tryptase measurement; its treatment is delayed, with little use of epinephrine; and its underlying cause or causes are poorly investigated. Deaths from anaphylaxis are difficult to investigate because of miscoding. Surprisingly, patients treated with new and powerful chemotherapy agents and humanized mAbs present with nonclassical symptoms of anaphylaxis, and patients may present with unrecognized clonal mast cell disorders with KIT mutations may present as Hymenoptera-induced or idiopathic anaphylaxis. The goal of this review is to recognize the presentations of anaphylaxis with the description of its current phenotypes, to provide new insight and understanding of its mechanisms and causes through its endotypes, and to address its biomarkers for broad clinical use. Ultimately, the aim is to empower allergists and heath care providers with new tools that can help alleviate patients' symptoms, preventing and protecting them against anaphylaxis.
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Affiliation(s)
- Mariana Castells
- Division of Rheumatology, Immunology and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass.
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59
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Reber LL, Hernandez JD, Galli SJ. The pathophysiology of anaphylaxis. J Allergy Clin Immunol 2017; 140:335-348. [PMID: 28780941 PMCID: PMC5657389 DOI: 10.1016/j.jaci.2017.06.003] [Citation(s) in RCA: 260] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/12/2017] [Accepted: 06/14/2017] [Indexed: 01/14/2023]
Abstract
Anaphylaxis is a severe systemic hypersensitivity reaction that is rapid in onset; characterized by life-threatening airway, breathing, and/or circulatory problems; and usually associated with skin and mucosal changes. Because it can be triggered in some persons by minute amounts of antigen (eg, certain foods or single insect stings), anaphylaxis can be considered the most aberrant example of an imbalance between the cost and benefit of an immune response. This review will describe current understanding of the immunopathogenesis and pathophysiology of anaphylaxis, focusing on the roles of IgE and IgG antibodies, immune effector cells, and mediators thought to contribute to examples of the disorder. Evidence from studies of anaphylaxis in human subjects will be discussed, as well as insights gained from analyses of animal models, including mice genetically deficient in the antibodies, antibody receptors, effector cells, or mediators implicated in anaphylaxis and mice that have been "humanized" for some of these elements. We also review possible host factors that might influence the occurrence or severity of anaphylaxis. Finally, we will speculate about anaphylaxis from an evolutionary perspective and argue that, in the context of severe envenomation by arthropods or reptiles, anaphylaxis might even provide a survival advantage.
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Affiliation(s)
- Laurent L Reber
- Department of Immunology, Unit of Antibodies in Therapy and Pathology, Institut Pasteur, Paris, France; Institut National de la Santé et de la Recherche Médicale, Paris, France; Department of Pathology, Stanford University School of Medicine, Stanford, Calif; Sean N. Parker Center for Allergy and Asthma Research, Stanford University School of Medicine, Stanford, Calif
| | - Joseph D Hernandez
- Department of Pediatrics, Division of Allergy, Immunology and Rheumatology, Stanford University School of Medicine, Stanford, Calif
| | - Stephen J Galli
- Department of Pathology, Stanford University School of Medicine, Stanford, Calif; Sean N. Parker Center for Allergy and Asthma Research, Stanford University School of Medicine, Stanford, Calif; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, Calif.
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60
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Epp A, Hobusch J, Bartsch YC, Petry J, Lilienthal GM, Koeleman CAM, Eschweiler S, Möbs C, Hall A, Morris SC, Braumann D, Engellenner C, Bitterling J, Rahmöller J, Leliavski A, Thurmann R, Collin M, Moremen KW, Strait RT, Blanchard V, Petersen A, Gemoll T, Habermann JK, Petersen F, Nandy A, Kahlert H, Hertl M, Wuhrer M, Pfützner W, Jappe U, Finkelman FD, Ehlers M. Sialylation of IgG antibodies inhibits IgG-mediated allergic reactions. J Allergy Clin Immunol 2017; 141:399-402.e8. [PMID: 28728998 DOI: 10.1016/j.jaci.2017.06.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 05/31/2017] [Accepted: 06/14/2017] [Indexed: 01/09/2023]
Affiliation(s)
- Alexandra Epp
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck & University Medical Center Schleswig Holstein, Lübeck, Germany
| | - Juliane Hobusch
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck & University Medical Center Schleswig Holstein, Lübeck, Germany
| | - Yannic C Bartsch
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck & University Medical Center Schleswig Holstein, Lübeck, Germany
| | - Janina Petry
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck & University Medical Center Schleswig Holstein, Lübeck, Germany
| | - Gina-Maria Lilienthal
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck & University Medical Center Schleswig Holstein, Lübeck, Germany
| | - Carolien A M Koeleman
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - Simon Eschweiler
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck & University Medical Center Schleswig Holstein, Lübeck, Germany
| | - Christian Möbs
- Department of Dermatology and Allergology, Philipps University Marburg, Marburg, Germany
| | - Ashley Hall
- Division of Emergency Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Suzanne C Morris
- Division of Immunology, Allergy and Rheumatology, Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Dominique Braumann
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck & University Medical Center Schleswig Holstein, Lübeck, Germany; Laboratory of Glycodesign and Glycoanalytics, Institute for Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-University Medicine Berlin, Berlin, Germany
| | - Christine Engellenner
- Division of Biochemical Immunology, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Borstel, Germany
| | - Josephine Bitterling
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck & University Medical Center Schleswig Holstein, Lübeck, Germany
| | - Johann Rahmöller
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck & University Medical Center Schleswig Holstein, Lübeck, Germany; Department of Anesthesiology and Intensive Care, University Medical Center Schleswig Holstein, Lübeck, Germany
| | - Alexei Leliavski
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck & University Medical Center Schleswig Holstein, Lübeck, Germany
| | - Robina Thurmann
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck & University Medical Center Schleswig Holstein, Lübeck, Germany
| | - Mattias Collin
- Division of Infection Medicine, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Kelley W Moremen
- Complex Carbohydrate Research Center, University of Georgia, Athens, Ga
| | - Richard T Strait
- Division of Emergency Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Véronique Blanchard
- Laboratory of Glycodesign and Glycoanalytics, Institute for Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-University Medicine Berlin, Berlin, Germany
| | - Arnd Petersen
- Division of Clinical & Molecular Allergology, Research Center Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany
| | - Timo Gemoll
- Section for Translational Surgical Oncology & Biobanking, Department of Surgery, University of Lübeck & Univesity Medical Center Schleswig Holstein, Lübeck, Germany
| | - Jens K Habermann
- Section for Translational Surgical Oncology & Biobanking, Department of Surgery, University of Lübeck & Univesity Medical Center Schleswig Holstein, Lübeck, Germany
| | - Frank Petersen
- Division of Biochemical Immunology, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Borstel, Germany
| | - Andreas Nandy
- Research and Preclinical Development, Allergopharma GmbH & Co. KG, a business of Merck, Darmstadt, Germany
| | - Helga Kahlert
- Research and Preclinical Development, Allergopharma GmbH & Co. KG, a business of Merck, Darmstadt, Germany
| | - Michael Hertl
- Department of Dermatology and Allergology, Philipps University Marburg, Marburg, Germany
| | - Manfred Wuhrer
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - Wolfgang Pfützner
- Department of Dermatology and Allergology, Philipps University Marburg, Marburg, Germany
| | - Uta Jappe
- Division of Clinical & Molecular Allergology, Research Center Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany; Interdisciplinary Allergy Outpatient Clinic, Department of Internal Medicine, University of Lübeck, Lübeck, Germany
| | - Fred D Finkelman
- Division of Immunology, Allergy and Rheumatology, Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio; Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Medicine, Cincinnati Veterans Affairs Medical Center, Cincinnati, Ohio
| | - Marc Ehlers
- Laboratories of Immunology and Antibody Glycan Analysis, Institute for Nutrition Medicine, University of Lübeck & University Medical Center Schleswig Holstein, Lübeck, Germany.
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61
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Epp A, Sullivan KC, Herr AB, Strait RT. Immunoglobulin Glycosylation Effects in Allergy and Immunity. Curr Allergy Asthma Rep 2017; 16:79. [PMID: 27796794 DOI: 10.1007/s11882-016-0658-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW The aim of this review will be to familiarize the reader with the general area of antibody (Ab) glycosylation and to summarize the known functional roles of glycosylation and how glycan structure can contribute to various disease states with emphasis on allergic disease. RECENT FINDINGS Both immunoglobulin (Ig) isotype and conserved Fc glycosylation sites often dictate the downstream activity of an Ab where complexity and degree of glycosylation contribute to its ability to bind Fc receptors (FcRs) and activate complement. Most information on the effects of glycosylation center on IgG in cancer therapy and autoimmunity. In cancer therapy, glycosylation modifications that enhance affinity for activating FcRs are utilized to facilitate immune-mediated tumor cell killing. In autoimmunity, disease severity has been linked to alterations in the presence, location, and composition of Fc glycans. Significantly less is understood about the role of glycosylation in the setting of allergy and asthma. However, recent data demonstrate that glycosylation of IgE at the asparagine-394 site of Cε3 is necessary for IgE interaction with the high affinity IgE receptor but, surprisingly, glycosylation has no effect on IgE interaction with its low-affinity lectin receptor, CD23. Variations in the specific glycoform may modulate the interaction of an Ig with its receptors. Significantly more is known about the functional effects of glycosylation of IgG than for other Ig isotypes. Thus, the role of glycosylation is much better understood in the areas of autoimmunity and cancer therapy, where IgG is the dominant isotype, than in the field of allergy, where IgE predominates. Further work is needed to fully understand the role of glycan variation in IgE and other Ig isotypes with regard to the inhibition or mediation of allergic disease.
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Affiliation(s)
- Alexandra Epp
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
| | - Kathryn C Sullivan
- Immunology Graduate Program, Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Andrew B Herr
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Richard T Strait
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH, USA. .,Division of Emergency Medicine, Cincinnati Children's Hospital, 3333 Burnet Ave, ML 2008, Cincinnati, OH, 45229, USA.
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62
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Emerging roles of basophils in allergic inflammation. Allergol Int 2017; 66:382-391. [PMID: 28506528 DOI: 10.1016/j.alit.2017.04.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 04/12/2017] [Accepted: 04/13/2017] [Indexed: 12/24/2022] Open
Abstract
Basophils have long been neglected in immunological studies because they were regarded as only minor relatives of mast cells. However, recent advances in analytical tools for basophils have clarified the non-redundant roles of basophils in allergic inflammation. Basophils play crucial roles in both IgE-dependent and -independent allergic inflammation, through their migration to the site of inflammation and secretion of various mediators, including cytokines, chemokines, and proteases. Basophils are known to produce large amounts of IL-4 in response to various stimuli. Basophil-derived IL-4 has recently been shown to play versatile roles in allergic inflammation by acting on various cell types, including macrophages, innate lymphoid cells, fibroblasts, and endothelial cells. Basophil-derived serine proteases are also crucial for the aggravation of allergic inflammation. Moreover, recent reports suggest the roles of basophils in modulating adaptive immune responses, particularly in the induction of Th2 differentiation and enhancement of humoral memory responses. In this review, we will discuss recent advances in understanding the roles of basophils in allergic inflammation.
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63
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Jensen-Jarolim E, Pali-Schöll I, Roth-Walter F. Outstanding animal studies in allergy I. From asthma to food allergy and anaphylaxis. Curr Opin Allergy Clin Immunol 2017; 17:169-179. [PMID: 28346234 PMCID: PMC5424575 DOI: 10.1097/aci.0000000000000363] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
PURPOSE OF REVIEW Animal models published within the past 18 months on asthma, food allergy and anaphylaxis, all conditions of rising public health concern, were reviewed. RECENT FINDINGS While domestic animals spontaneously develop asthma, food allergy and anaphylaxis, in animal models, divergent sensitization and challenge routes, dosages, intervals and antigens are used to induce asthmatic, food allergic or anaphylactic phenotypes. This must be considered in the interpretation of results. Instead of model antigens, gradually relevant allergens such as house dust mite in asthma, and food allergens like peanut, apple and peach in food allergy research were used. Novel engineered mouse models such as a mouse with a T-cell receptor for house dust mite allergen Der p 1, or with transgenic human hFcγR genes, facilitated the investigation of single molecules of interest. Whole-body plethysmography has become a state-of-the-art in-vivo readout in asthma research. In food allergy and anaphylaxis research, novel techniques were developed allowing real-time monitoring of in-vivo effects following allergen challenge. Networks to share tissues were established as an effort to reduce animal experiments in allergy which cannot be replaced by in-vitro measures. SUMMARY Natural and artificial animal models were used to explore the pathophysiology of asthma, food allergy and anaphylaxis and to improve prophylactic and therapeutic measures. Especially the novel mouse models mimicking molecular aspects of the complex immune network in asthma, food allergy and anaphylaxis will facilitate proof-of-concept studies under controlled conditions.
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Affiliation(s)
- Erika Jensen-Jarolim
- Institute of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna
- The Interuniversity Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University Vienna, University of Vienna, Vienna, Austria
| | - Isabella Pali-Schöll
- The Interuniversity Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University Vienna, University of Vienna, Vienna, Austria
| | - Franziska Roth-Walter
- The Interuniversity Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University Vienna, University of Vienna, Vienna, Austria
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64
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Escribese MM, Rosace D, Chivato T, Fernández TD, Corbí AL, Barber D. Alternative Anaphylactic Routes: The Potential Role of Macrophages. Front Immunol 2017; 8:515. [PMID: 28533777 PMCID: PMC5421149 DOI: 10.3389/fimmu.2017.00515] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 04/18/2017] [Indexed: 01/07/2023] Open
Abstract
Anaphylaxis is an acute, life-threatening, multisystem syndrome resulting from the sudden release of mediators from effector cells. There are two potential pathways for anaphylaxis. The first one, IgE-dependent anaphylaxis, is induced by antigen (Ag) cross-linking of Ag-specific IgE bound to the high-affinity IgE receptor (FcεRI) on mast cells and basophils. The second one, IgG-dependent anaphylaxis is induced by Ag cross-linking of Ag-specific IgG bound to IgG receptors (FcγRI, FcγRIIA, FcγRIIB, FcγRIIC, and FcγRIIIA) on macrophages, neutrophils, and basophils. Macrophages exhibit a huge functional plasticity and are capable of exerting their scavenging, bactericidal, and regulatory functions under a wide variety of tissue conditions. Herein, we will review their potential role in the triggering and development of anaphylaxis. Thereby, macrophages, among other immune cells, play a role in both anaphylactic pathways (1) by responding to anaphylactic mediators secreted by mast cells after specific IgE cross-linking or (2) by acting as effector cells in the anaphylactic response mediated by IgG. In this review, we will go over the cellular and molecular mechanisms that take place in the above-mentioned anaphylactic pathways and will discuss the clinical implications in human allergic reactions.
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Affiliation(s)
- María M Escribese
- Faculty of Medicine, IMMA Applied Molecular Medicine Institute, CEU San Pablo University, Madrid, Spain.,Faculty of Medicine, Basic Medical Sciences Department, CEU San Pablo University, Madrid, Spain
| | - Domenico Rosace
- Faculty of Medicine, IMMA Applied Molecular Medicine Institute, CEU San Pablo University, Madrid, Spain
| | - Tomas Chivato
- Faculty of Medicine, Basic Medical Sciences Department, CEU San Pablo University, Madrid, Spain
| | - Tahia D Fernández
- Allergy Unit, Málaga Regional University Hospital-IBIMA, Málaga University, Málaga, Spain
| | - Angel L Corbí
- Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - Domingo Barber
- Faculty of Medicine, IMMA Applied Molecular Medicine Institute, CEU San Pablo University, Madrid, Spain
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65
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Burton OT, Tamayo JM, Stranks AJ, Koleoglou KJ, Oettgen HC. Allergen-specific IgG antibody signaling through FcγRIIb promotes food tolerance. J Allergy Clin Immunol 2017; 141:189-201.e3. [PMID: 28479335 DOI: 10.1016/j.jaci.2017.03.045] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 03/20/2017] [Accepted: 03/27/2017] [Indexed: 12/27/2022]
Abstract
BACKGROUND Patients with food allergy produce high-titer IgE antibodies that bind to mast cells through FcεRI and trigger immediate hypersensitivity reactions on antigen encounter. Food-specific IgG antibodies arise in the setting of naturally resolving food allergy and accompany the acquisition of food allergen unresponsiveness in oral immunotherapy. OBJECTIVE In this study we sought to delineate the effects of IgG and its inhibitory Fc receptor, FcγRIIb, on both de novo allergen sensitization in naive animals and on established immune responses in the setting of pre-existing food allergy. METHODS Allergen-specific IgG was administered to mice undergoing sensitization and desensitization to the model food allergen ovalbumin. Cellular and molecular mechanisms were interrogated by using mast cell- and FcγRIIb-deficient mice. The requirement for FcγRII in IgG-mediated inhibition of human mast cells was investigated by using a neutralizing antibody. RESULTS Administration of specific IgG to food allergy-prone IL4raF709 mice during initial food exposure prevented the development of IgE antibodies, TH2 responses, and anaphylactic responses on challenge. When given as an adjunct to oral desensitization in mice with established IgE-mediated hypersensitivity, IgG facilitated tolerance restoration, favoring expansion of forkhead box protein 3-positive regulatory T cells along with suppression of existing TH2 and IgE responses. IgG and FcγRIIb suppress adaptive allergic responses through effects on mast cell function. CONCLUSION These findings suggest that allergen-specific IgG antibodies can act to induce and sustain immunologic tolerance to foods.
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Affiliation(s)
- Oliver T Burton
- Department of Medicine, Boston Children's Hospital, Boston, Mass; Department of Pediatrics, Harvard Medical School, Boston, Mass.
| | - Jaciel M Tamayo
- Department of Medicine, Boston Children's Hospital, Boston, Mass; Department of Pediatrics, Harvard Medical School, Boston, Mass
| | - Amanda J Stranks
- Department of Medicine, Boston Children's Hospital, Boston, Mass; Department of Pediatrics, Harvard Medical School, Boston, Mass
| | - Kyle J Koleoglou
- Department of Medicine, Boston Children's Hospital, Boston, Mass
| | - Hans C Oettgen
- Department of Medicine, Boston Children's Hospital, Boston, Mass; Department of Pediatrics, Harvard Medical School, Boston, Mass
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66
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Balbino B, Sibilano R, Starkl P, Marichal T, Gaudenzio N, Karasuyama H, Bruhns P, Tsai M, Reber LL, Galli SJ. Pathways of immediate hypothermia and leukocyte infiltration in an adjuvant-free mouse model of anaphylaxis. J Allergy Clin Immunol 2017; 139:584-596.e10. [PMID: 27555460 PMCID: PMC5241268 DOI: 10.1016/j.jaci.2016.05.047] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 05/16/2016] [Accepted: 05/31/2016] [Indexed: 01/07/2023]
Abstract
BACKGROUND Conflicting results have been obtained regarding the roles of Fc receptors and effector cells in models of active systemic anaphylaxis (ASA). In part, this might reflect the choice of adjuvant used during sensitization because various adjuvants might differentially influence the production of particular antibody isotypes. OBJECTIVE We developed an "adjuvant-free" mouse model of ASA and assessed the contributions of components of the "classical" and "alternative" pathways in this model. METHODS Mice were sensitized intraperitoneally with ovalbumin at weekly intervals for 6 weeks and challenged intraperitoneally with ovalbumin 2 weeks later. RESULTS Wild-type animals had immediate hypothermia and late-phase intraperitoneal inflammation in this model. These features were reduced in mice lacking the IgE receptor FcεRI, the IgG receptor FcγRIII or the common γ-chain FcRγ. FcγRIV blockade resulted in a partial reduction of inflammation without any effect on hypothermia. Depletion of monocytes/macrophages with clodronate liposomes significantly reduced the hypothermia response. By contrast, depletion of neutrophils or basophils had no significant effects in this ASA model. Both the hypothermia and inflammation were dependent on platelet-activating factor and histamine and were reduced in 2 types of mast cell (MC)-deficient mice. Finally, engraftment of MC-deficient mice with bone marrow-derived cultured MCs significantly exacerbated the hypothermia response and restored inflammation to levels similar to those observed in wild-type mice. CONCLUSION Components of the classical and alternative pathways contribute to anaphylaxis in this adjuvant-free model, with key roles for MCs and monocytes/macrophages.
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MESH Headings
- Adjuvants, Immunologic
- Anaphylaxis/immunology
- Animals
- Cell Movement
- Cells, Cultured
- Complement Pathway, Alternative
- Complement Pathway, Classical
- Disease Models, Animal
- Humans
- Hypothermia/immunology
- Immunization
- Leukocytes/immunology
- Macrophages/immunology
- Mast Cells/immunology
- Mast Cells/transplantation
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Receptors, IgE/genetics
- Receptors, IgE/metabolism
- Receptors, IgG/genetics
- Receptors, IgG/metabolism
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Affiliation(s)
- Bianca Balbino
- Institut Pasteur, Department of Immunology, Unit of Antibodies in Therapy and Pathology, Paris, France; INSERM, U1222, Paris, France; Université Pierre et Marie Curie, Paris, France
| | - Riccardo Sibilano
- Department of Pathology, Stanford University School of Medicine, Stanford, Calif; Sean N. Parker Center for Allergy and Asthma Research, Stanford University School of Medicine, Stanford, Calif
| | - Philipp Starkl
- Department of Pathology, Stanford University School of Medicine, Stanford, Calif; Sean N. Parker Center for Allergy and Asthma Research, Stanford University School of Medicine, Stanford, Calif
| | - Thomas Marichal
- Department of Pathology, Stanford University School of Medicine, Stanford, Calif
| | - Nicolas Gaudenzio
- Department of Pathology, Stanford University School of Medicine, Stanford, Calif; Sean N. Parker Center for Allergy and Asthma Research, Stanford University School of Medicine, Stanford, Calif
| | - Hajime Karasuyama
- Department of Immune Regulation, Tokyo Medical and Dental University, Graduate School of Medical and Dental Sciences, Tokyo, Japan
| | - Pierre Bruhns
- Institut Pasteur, Department of Immunology, Unit of Antibodies in Therapy and Pathology, Paris, France; INSERM, U1222, Paris, France
| | - Mindy Tsai
- Department of Pathology, Stanford University School of Medicine, Stanford, Calif; Sean N. Parker Center for Allergy and Asthma Research, Stanford University School of Medicine, Stanford, Calif
| | - Laurent L Reber
- Institut Pasteur, Department of Immunology, Unit of Antibodies in Therapy and Pathology, Paris, France; INSERM, U1222, Paris, France; Department of Pathology, Stanford University School of Medicine, Stanford, Calif; Sean N. Parker Center for Allergy and Asthma Research, Stanford University School of Medicine, Stanford, Calif.
| | - Stephen J Galli
- Department of Pathology, Stanford University School of Medicine, Stanford, Calif; Sean N. Parker Center for Allergy and Asthma Research, Stanford University School of Medicine, Stanford, Calif; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, Calif.
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Mechanisms of anaphylaxis in human low-affinity IgG receptor locus knock-in mice. J Allergy Clin Immunol 2016; 139:1253-1265.e14. [PMID: 27568081 DOI: 10.1016/j.jaci.2016.06.058] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 05/13/2016] [Accepted: 06/13/2016] [Indexed: 12/13/2022]
Abstract
BACKGROUND Anaphylaxis can proceed through distinct IgE- or IgG-dependent pathways, which have been investigated in various mouse models. We developed a novel mouse strain in which the human low-affinity IgG receptor locus, comprising both activating (hFcγRIIA, hFcγRIIIA, and hFcγRIIIB) and inhibitory (hFcγRIIB) hFcγR genes, has been inserted into the equivalent murine locus, corresponding to a locus swap. OBJECTIVE We sought to determine the capabilities of hFcγRs to induce systemic anaphylaxis and identify the cell types and mediators involved. METHODS hFcγR expression on mouse and human cells was compared to validate the model. Passive systemic anaphylaxis was induced by injection of heat-aggregated human intravenous immunoglobulin and active systemic anaphylaxis after immunization and challenge. Anaphylaxis severity was evaluated based on hypothermia and mortality. The contribution of receptors, mediators, or cell types was assessed based on receptor blockade or depletion. RESULTS The human-to-mouse low-affinity FcγR locus swap engendered hFcγRIIA/IIB/IIIA/IIIB expression in mice comparable with that seen in human subjects. Knock-in mice were susceptible to passive and active anaphylaxis, accompanied by downregulation of both activating and inhibitory hFcγR expression on specific myeloid cells. The contribution of hFcγRIIA was predominant. Depletion of neutrophils protected against hypothermia and mortality. Basophils contributed to a lesser extent. Anaphylaxis was inhibited by platelet-activating factor receptor or histamine receptor 1 blockade. CONCLUSION Low-affinity FcγR locus-switched mice represent an unprecedented model of cognate hFcγR expression. Importantly, IgG-related anaphylaxis proceeds within a native context of activating and inhibitory hFcγRs, indicating that, despite robust hFcγRIIB expression, activating signals can dominate to initiate a severe anaphylactic reaction.
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