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Ka Y, Ito R, Nozu R, Tomiyama K, Ueno M, Ogura T, Takahashi R. Establishment of a human microbiome- and immune system-reconstituted dual-humanized mouse model. Exp Anim 2023; 72:402-412. [PMID: 37019665 PMCID: PMC10435363 DOI: 10.1538/expanim.23-0025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 03/28/2023] [Indexed: 04/05/2023] Open
Abstract
Humanized mice are widely used to study the human immune system in vivo and investigate therapeutic targets for various human diseases. Immunodeficient NOD/Shi-scid-IL2rγnull (NOG) mice transferred with human hematopoietic stem cells are a useful model for studying human immune systems and analyzing engrafted human immune cells. The gut microbiota plays a significant role in the development and function of immune cells and the maintenance of immune homeostasis; however, there is currently no available animal model that has been reconstituted with human gut microbiota and immune systems in vivo. In this study, we established a new model of CD34+ cell-transferred humanized germ-free NOG mice using an aseptic method. Flow cytometric analysis revealed that the germ-free humanized mice exhibited a lower level of human CD3+ T cells than the SPF humanized mice. Additionally, we found that the human CD3+ T cells slightly increased after transplanting human gut microbiota into the germ-free humanized mice, suggesting that the human microbiota supports T cell proliferation or maintenance in humanized mice colonized by the gut microbiota. Consequently, the dual-humanized mice may be useful for investigating the physiological role of the gut microbiota in human immunity in vivo and for application as a new humanized mouse model in cancer immunology.
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Affiliation(s)
- Yuyo Ka
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
| | - Ryoji Ito
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
| | - Ryoko Nozu
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
| | - Kayo Tomiyama
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
| | - Masami Ueno
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
| | - Tomoyuki Ogura
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
| | - Riichi Takahashi
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan
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2
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Warmenhoven H, Leboux R, Bethanis A, van Strien J, Logiantara A, van Schijndel H, Aglas L, van Rijt L, Slütter B, Kros A, Jiskoot W, van Ree R. Cationic liposomes bearing Bet v 1 by coiled coil-formation are hypo-allergenic and induce strong immunogenicity in mice. FRONTIERS IN ALLERGY 2023; 3:1092262. [PMID: 36704756 PMCID: PMC9872006 DOI: 10.3389/falgy.2022.1092262] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023] Open
Abstract
Although aluminum hydroxide (alum) is widely accepted and used as safe vaccine adjuvant, there is some concern about possible toxicity upon long-lasting repeated exposure during subcutaneous allergen immunotherapy (SCIT). Our objective was to evaluate allergen-bearing liposomes as possible alternative for alum-adsorption in SCIT. A self-assembling, coiled-coil forming peptide pair was used to anchor the major birch pollen allergen Bet v 1 to the surface of cationic liposomes. The resulting nanoparticulate liposomes were characterized with respect to their physicochemical, allergenic and immunological properties. Allergenicity was studied by ImmunoCAP inhibition and rat basophil leukemia (RBL) cell assays. Immunogenicity (immunoglobulin responses) and immune skewing (cytokine responses) were evaluated upon immunization of naïve mice, and compared to alum-adsorbed Bet v 1. Bet v 1-bearing cationic liposomes with a diameter of ∼200 nm showed a positive zeta potential. The coiled-coil conjugation of Bet v 1 to the surface of liposomes resulted in about a 15-fold lower allergenicity than soluble Bet v 1 as judged by RBL assays. Moreover, the nanoparticles induced Bet v 1-specific IgG1/IgG2a responses in mice that were several orders of magnitude higher than those induced by alum-adsorbed Bet v 1. This strong humoral response was accompanied by a relatively strong IL-10 induction upon PBMC stimulation with Bet v 1. In conclusion, their hypo-allergenic properties, combined with their capacity to induce a strong humoral immune response and a relatively strong IL-10 production, makes these allergen-covered cationic liposomes a promising alternative for aluminum salt-adsorption of allergen currently used in SCIT.
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Affiliation(s)
- Hans Warmenhoven
- Department of Experimental Immunology, Amsterdam University Medical Centers, Location AMC, Amsterdam, Netherlands
- HAL Allergy BV, J.H. Oortweg, Leiden, Netherlands
| | - Romain Leboux
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, Netherlands
| | | | - Jolinde van Strien
- Department of Supramolecular & Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands
| | - Adrian Logiantara
- Department of Experimental Immunology, Amsterdam University Medical Centers, Location AMC, Amsterdam, Netherlands
| | | | - Lorenz Aglas
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | - Leonie van Rijt
- Department of Experimental Immunology, Amsterdam University Medical Centers, Location AMC, Amsterdam, Netherlands
| | - Bram Slütter
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, Netherlands
| | - Alexander Kros
- Department of Supramolecular & Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands
| | - Wim Jiskoot
- Division of BioTherapeutics, Leiden Academic Centre for Drug Research, Leiden University, Leiden, Netherlands
| | - Ronald van Ree
- Department of Experimental Immunology, Amsterdam University Medical Centers, Location AMC, Amsterdam, Netherlands
- Department of Otorhinolaryngology, Amsterdam University Medical Centers, Location AMC, Amsterdam, Netherlands
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3
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Wen J, Wang L, Ren J, Kranz E, Chen S, Wu D, Kanazawa T, Chen I, Lu Y, Kamata M. Nanoencapsulated rituximab mediates superior cellular immunity against metastatic B-cell lymphoma in a complement competent humanized mouse model. J Immunother Cancer 2021; 9:jitc-2020-001524. [PMID: 33593826 PMCID: PMC7888328 DOI: 10.1136/jitc-2020-001524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2020] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Despite the numerous applications of monoclonal antibodies (mAbs) in cancer therapeutics, animal models available to test the therapeutic efficacy of new mAbs are limited. NOD.Cg-Prkdcscid Il2rg tm1Wjl /SzJ (NSG) mice are one of the most highly immunodeficient strains and are universally used as a model for testing cancer-targeting mAbs. However, this strain lacks several factors necessary to fully support antibody-mediated effector functions-including antibody-dependent cellular cytotoxicity, antibody-dependent cellular phagocytosis, and complement-dependent cytotoxicity (CDC)-due to the absence of immune cells as well as a mutation in the Hc gene, which is needed for a functional complement system. METHODS We have developed a humanized mouse model using a novel NSG strain, NOD.Cg-Hc1 Prkdcscid Il2rgtm1Wjl/SzJ (NSG-Hc1), which contains the corrected mutation in the Hc gene to support CDC in addition to other mechanisms endowed by humanization. With this model, we reevaluated the anticancer efficacies of nanoencapsulated rituximab after xenograft of the human Burkitt lymphoma cell line 2F7-BR44. RESULTS As expected, xenografted humanized NSG-Hc1 mice supported superior lymphoma clearance of native rituximab compared with the parental NSG strain. Nanoencapsulated rituximab with CXCL13 conjugation as a targeting ligand for lymphomas further enhanced antilymphoma activity in NSG-Hc1 mice and, more importantly, mediated antilymphoma cellular responses. CONCLUSIONS These results indicate that NSG-Hc1 mice can serve as a feasible model for both studying antitumor treatment using cancer targeting as well as understanding induction mechanisms of antitumor cellular immune response.
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Affiliation(s)
- Jing Wen
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.,UCLA AIDS Institute, University of California Los Angeles, Los Angeles, California, USA
| | - Lan Wang
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.,UCLA AIDS Institute, University of California Los Angeles, Los Angeles, California, USA
| | - Jie Ren
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles, Los Angeles, California, USA
| | - Emiko Kranz
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.,UCLA AIDS Institute, University of California Los Angeles, Los Angeles, California, USA
| | - Shilin Chen
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles, Los Angeles, California, USA
| | - Di Wu
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles, Los Angeles, California, USA
| | - Toshio Kanazawa
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.,UCLA AIDS Institute, University of California Los Angeles, Los Angeles, California, USA
| | - Irvin Chen
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.,UCLA AIDS Institute, University of California Los Angeles, Los Angeles, California, USA
| | - Yunfeng Lu
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles, Los Angeles, California, USA
| | - Masakazu Kamata
- Microbiology, University of Alabama at Birmingham School of Arts and Humanities, Birmingham, Alabama, USA
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Thapaliya M, Chompunud Na Ayudhya C, Amponnawarat A, Roy S, Ali H. Mast Cell-Specific MRGPRX2: a Key Modulator of Neuro-Immune Interaction in Allergic Diseases. Curr Allergy Asthma Rep 2021; 21:3. [PMID: 33398613 DOI: 10.1007/s11882-020-00979-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2020] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW Atopic dermatitis (AD) and allergic asthma are complex disorders with significant public health burden. This review provides an overview of the recent developments on Mas-related G protein-coupled receptor-X2 (MRGPRX2; mouse counterpart MrgprB2) as a potential candidate to target neuro-immune interaction in AD and allergic asthma. RECENT FINDINGS Domestic allergens directly activate sensory neurons to release substance P (SP), which induces mast cell degranulation via MrgprB2 and drives type 2 skin inflammation in AD. MRGPRX2 expression is upregulated in human lung mast cells and serum of asthmatic patients. Both SP and hemokinin-1 (HK-1 generated from macrophages, bronchial cells, and mast cells) cause degranulation of human mast cells via MRGPRX2. MrgprB2 contributes to mast cell-nerve interaction in the pathogenesis of AD. Furthermore, asthma severity is associated with increased MRGPRX2 expression in mast cells. Thus, MRGPRX2 could serve as a novel target for modulating AD and asthma.
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Affiliation(s)
- Monica Thapaliya
- Department of Basic and Translational Sciences, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, 19104, USA
| | - Chalatip Chompunud Na Ayudhya
- Department of Basic and Translational Sciences, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, 19104, USA
| | - Aetas Amponnawarat
- Department of Basic and Translational Sciences, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, 19104, USA
| | - Saptarshi Roy
- Department of Basic and Translational Sciences, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, 19104, USA
| | - Hydar Ali
- Department of Basic and Translational Sciences, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, 19104, USA.
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5
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Ka Y, Katano I, Nishinaka E, Welcker J, Mochizuki M, Kawai K, Goto M, Tomiyama K, Ogura T, Yamamoto T, Ito M, Ito R, Takahashi R. Improved engraftment of human peripheral blood mononuclear cells in NOG MHC double knockout mice generated using CRISPR/Cas9. Immunol Lett 2020; 229:55-61. [PMID: 33253759 DOI: 10.1016/j.imlet.2020.11.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 11/23/2020] [Indexed: 12/21/2022]
Abstract
Humanized mice are widely used to study the human immune system in vivo and develop therapies for various human diseases. Human peripheral blood mononuclear cells (PBMC)-engrafted NOD/Shi-scid IL2rγnull (NOG) mice are useful models for characterization of human T cells. However, the development of graft-versus-host disease (GVHD) limits the use of NOG PBMC models. We previously established a NOG-major histocompatibility complex class I/II double knockout (dKO) mouse model. Although humanized dKO mice do not develop severe GVHD, they have impaired reproductive performance and reduced chimerism of human cells. In this study, we established a novel beta-2 microglobulin (B2m) KO mouse model using CRISPR/Cas9. By crossing B2m KO mice with I-Ab KO mice, we established a modified dKO (dKO-em) mouse model. Reproductivity was slightly improved in dKO-em mice, compared with conventional dKO (dKO-tm) mice. dKO-em mice showed no signs of GVHD after the transfer of human PBMCs; they also exhibited high engraftment efficiency. Engrafted human PBMCs survived significantly longer in the peripheral blood and spleens of dKO-em mice, compared with dKO-tm mice. In conclusion, dKO-em mice might constitute a promising PBMC-based humanized mouse model for the development and preclinical testing of novel therapeutics for human diseases.
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Affiliation(s)
- Yuyo Ka
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan.
| | - Ikumi Katano
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan
| | - Eiko Nishinaka
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan
| | - Jochen Welcker
- Taconic Biosciences, Inc., 1 Discovery Drive, Suite 304, Rensselaer, NY, 12144, United States
| | - Misa Mochizuki
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan
| | - Kenji Kawai
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan
| | - Motohito Goto
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan
| | - Kayo Tomiyama
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan
| | - Tomoyuki Ogura
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan
| | - Taichi Yamamoto
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan
| | - Mamoru Ito
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan
| | - Ryoji Ito
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan.
| | - Riichi Takahashi
- Central Institute for Experimental Animals, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan.
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6
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Holgado A, Braun H, Verstraete K, Vanneste D, Callewaert N, Savvides SN, Afonina IS, Beyaert R. Single-Chain Soluble Receptor Fusion Proteins as Versatile Cytokine Inhibitors. Front Immunol 2020; 11:1422. [PMID: 32754154 PMCID: PMC7370943 DOI: 10.3389/fimmu.2020.01422] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 06/02/2020] [Indexed: 01/08/2023] Open
Abstract
Cytokines are small secreted proteins that among many functions also play key roles in the orchestration of inflammation in host defense and disease. Over the past years, a large number of biologics have been developed to target cytokines in disease, amongst which soluble receptor fusion proteins have shown some promise in pre-clinical studies. We have previously shown proof-of-concept for the therapeutic targeting of interleukin (IL)-33 in airway inflammation using a newly developed biologic, termed IL-33trap, comprising the ectodomains of the cognate receptor ST2 and the co-receptor IL-1RAcP fused into a single-chain recombinant fusion protein. Here we extend the biophysical and biological characterization of IL-33trap variants, and show that IL-33trap is a stable protein with a monomeric profile both at physiological temperatures and during liquid storage at 4°C. Reducing the N-glycan heterogeneity and complexity of IL-33trap via GlycoDelete engineering neither affects its stability nor its inhibitory activity against IL-33. We also report that IL-33trap specifically targets biologically active IL-33 splice variants. Finally, we document the generation and antagonistic activity of a single-chain IL-4/13trap, which inhibits both IL-4 and IL-13 signaling. Collectively, these results illustrate that single-chain soluble receptor fusion proteins against IL-4, IL-13, and IL-33 are novel biologics that might not only be of interest for research purposes and further interrogation of the role of their target cytokines in physiology and disease, but may also complement monoclonal antibodies for the treatment of allergic and other inflammatory diseases.
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Affiliation(s)
- Aurora Holgado
- Center for Inflammation Research, Unit of Molecular Signal Transduction in Inflammation, VIB, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Harald Braun
- Center for Inflammation Research, Unit of Molecular Signal Transduction in Inflammation, VIB, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Kenneth Verstraete
- Center for Inflammation Research, Unit for Structural Biology, VIB, Ghent, Belgium.,Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Domien Vanneste
- Center for Inflammation Research, Unit of Molecular Signal Transduction in Inflammation, VIB, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Nico Callewaert
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium.,Center for Medical Biotechnology, VIB, Ghent, Belgium
| | - Savvas N Savvides
- Center for Inflammation Research, Unit for Structural Biology, VIB, Ghent, Belgium.,Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Inna S Afonina
- Center for Inflammation Research, Unit of Molecular Signal Transduction in Inflammation, VIB, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Rudi Beyaert
- Center for Inflammation Research, Unit of Molecular Signal Transduction in Inflammation, VIB, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
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7
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Tan KS, Lim RL, Liu J, Ong HH, Tan VJ, Lim HF, Chung KF, Adcock IM, Chow VT, Wang DY. Respiratory Viral Infections in Exacerbation of Chronic Airway Inflammatory Diseases: Novel Mechanisms and Insights From the Upper Airway Epithelium. Front Cell Dev Biol 2020; 8:99. [PMID: 32161756 PMCID: PMC7052386 DOI: 10.3389/fcell.2020.00099] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/07/2020] [Indexed: 12/16/2022] Open
Abstract
Respiratory virus infection is one of the major sources of exacerbation of chronic airway inflammatory diseases. These exacerbations are associated with high morbidity and even mortality worldwide. The current understanding on viral-induced exacerbations is that viral infection increases airway inflammation which aggravates disease symptoms. Recent advances in in vitro air-liquid interface 3D cultures, organoid cultures and the use of novel human and animal challenge models have evoked new understandings as to the mechanisms of viral exacerbations. In this review, we will focus on recent novel findings that elucidate how respiratory viral infections alter the epithelial barrier in the airways, the upper airway microbial environment, epigenetic modifications including miRNA modulation, and other changes in immune responses throughout the upper and lower airways. First, we reviewed the prevalence of different respiratory viral infections in causing exacerbations in chronic airway inflammatory diseases. Subsequently we also summarized how recent models have expanded our appreciation of the mechanisms of viral-induced exacerbations. Further we highlighted the importance of the virome within the airway microbiome environment and its impact on subsequent bacterial infection. This review consolidates the understanding of viral induced exacerbation in chronic airway inflammatory diseases and indicates pathways that may be targeted for more effective management of chronic inflammatory diseases.
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Affiliation(s)
- Kai Sen Tan
- Department of Otolaryngology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Rachel Liyu Lim
- Infectious Disease Research and Training Office, National Centre for Infectious Diseases, Singapore, Singapore
| | - Jing Liu
- Department of Otolaryngology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Hsiao Hui Ong
- Department of Otolaryngology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Vivian Jiayi Tan
- Department of Otolaryngology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Hui Fang Lim
- Division of Respiratory and Critical Care Medicine, National University Hospital, Singapore, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Kian Fan Chung
- Airway Disease, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Ian M Adcock
- Airway Disease, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Vincent T Chow
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - De Yun Wang
- Department of Otolaryngology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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