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Xia X, Li J, Liang R, Li Y, Ma X, Yang Y, Lozano-Ojalvo D. Effects of unfolding treatment assisted glycation on the IgE/IgG binding capacity and antioxidant activity of ovomucoid. Food Funct 2024; 15:196-207. [PMID: 38047408 DOI: 10.1039/d3fo04035f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Ovomucoid is the immune-dominant allergen in the egg white of hens. Due to its structure based on nine disulfide bonds as well as its resistance to heat and enzymatic hydrolysis, the allergenicity of this food protein is difficult to decrease by technological processes. We sought to reduce its allergenicity through the Maillard reaction. The unfolding of ovomucoid with L-cysteine-mediated reduction was used to increase accessibility to conformational and linear epitopes by modifying the secondary and tertiary structures of the allergen. Glycation with different saccharides revealed the beneficial effect of maltose glycation on the IgG-binding capacity reduction. By determining the better glycation conditions of unfolded ovomucoid, we produced ovomucoid with reduced IgE binding capacity due to the glycation sites (K17, K112, K129, and K164) on epitopes. Moreover, after simulated infant and adult gastrointestinal digestion, the unfolded plus glycated ovomucoid showed higher ABTS˙+ scavenging activity, O2˙- scavenging activity, ˙OH scavenging activity, Fe2+ chelating activity, and a FRAP value; in particular, for ˙OH scavenging activity, there was a sharp increase of more than 100%.
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Affiliation(s)
- Xian Xia
- School of Public Health, Zunyi Medical University, Zunyi 563000, China.
| | - Jiangdong Li
- School of Public Health, Zunyi Medical University, Zunyi 563000, China.
| | - Rui Liang
- School of Public Health, Zunyi Medical University, Zunyi 563000, China.
| | - Yi Li
- School of Public Health, Zunyi Medical University, Zunyi 563000, China.
| | - Xiaojuan Ma
- School of Public Health, Zunyi Medical University, Zunyi 563000, China.
- Key Laboratory of Maternal & Child Health and Exposure Science of Guizhou Higher Education Institutes, Zunyi 563000, China
| | - Ying Yang
- Department of Dermatology, The Second Affiliated Hospital of Zunyi Medical University, Zunyi 563000, China
| | - Daniel Lozano-Ojalvo
- Instituto de Investigaciónen Ciencias de la Alimentación (CIAL, CSIC), Madrid 28049, Spain
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Leau A, Denery‐Papini S, Bodinier M, Dijk W. Tolerance to heated egg in egg allergy: Explanations and implications for prevention and treatment. Clin Transl Allergy 2023; 13:e12312. [PMID: 38146801 PMCID: PMC10734553 DOI: 10.1002/clt2.12312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/02/2023] [Accepted: 10/26/2023] [Indexed: 12/27/2023] Open
Abstract
Hen's egg allergy is the second most frequent food allergy found in children. Allergic symptoms can be caused by raw or heated egg, but a majority of egg-allergic children can tolerate hard-boiled or baked egg. Understanding the reasons for the tolerance towards heated egg provides clues about the molecular mechanisms involved in egg allergy, and the differential allergenicity of heated and baked egg might be exploited to prevent or treat egg allergy. In this review, we therefore discuss (i) why some patients are able to tolerate heated egg; by highlighting the structural changes of egg white (EW) proteins upon heating and their impact on immunoreactivity, as well as patient characteristics, and (ii) to what extent heated or baked EW might be useful for primary prevention strategies or oral immunotherapy. We describe that the level of immunoreactivity towards EW helps to discriminate patients tolerant or reactive to heated or baked egg. Furthermore, the use of heated or baked egg seems effective in primary prevention strategies and might limit adverse reactions. Oral immunotherapy is a promising treatment strategy, but it can sometimes cause significant adverse events. The use of heated or baked egg might limit these, but current literature is insufficient to conclude about its efficacy.
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Fakhimahmadi A, Hasanaj I, Hofstetter G, Pogner C, Gorfer M, Wiederstein M, Szepannek N, Bianchini R, Dvorak Z, Jensen SA, Berger M, Jensen-Jarolim E, Hufnagl K, Roth-Walter F. Nutritional Provision of Iron Complexes by the Major Allergen Alt a 1 to Human Immune Cells Decreases Its Presentation. Int J Mol Sci 2023; 24:11934. [PMID: 37569310 PMCID: PMC10418924 DOI: 10.3390/ijms241511934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/14/2023] [Accepted: 07/20/2023] [Indexed: 08/13/2023] Open
Abstract
Alternaria alternata is a common fungus strongly related with severe allergic asthma, with 80% of affected individuals being sensitized solely to its major allergen Alt a 1. Here, we assessed the function of Alt a 1 as an innate defense protein binding to micronutrients, such as iron-quercetin complexes (FeQ2), and its impact on antigen presentation in vitro. Binding of Alt a 1 to FeQ2 was determined in docking calculations. Recombinant Alt a 1 was generated, and binding ability, as well as secondary and quaternary structure, assessed by UV-VIS, CD, and DLS spectroscopy. Proteolytic functions were determined by casein and gelatine zymography. Uptake of empty apo- or ligand-filled holoAlt a 1 were assessed in human monocytic THP1 cells under the presence of dynamin and clathrin-inhibitors, activation of the Arylhydrocarbon receptor (AhR) using the human reporter cellline AZ-AHR. Human PBMCs were stimulated and assessed for phenotypic changes in monocytes by flow cytometry. Alt a 1 bound strongly to FeQ2 as a tetramer with calculated Kd values reaching pico-molar levels and surpassing affinities to quercetin alone by a factor of 5000 for the tetramer. apoAlt a 1 but not holoAlta 1 showed low enzymatic activity against casein as a hexamer and gelatin as a trimer. Uptake of apo- and holo-Alt a 1 occurred partly clathrin-dependent, with apoAlt a 1 decreasing labile iron in THP1 cells and holoAlt a 1 facilitating quercetin-dependent AhR activation. In human PBMCs uptake of holoAlt a 1 but not apoAlt a 1 significantly decreased the surface expression of the costimulatory CD86, but also of HLADR, thereby reducing effective antigen presentation. We show here for the first time that the presence of nutritional iron complexes, such as FeQ2, significantly alters the function of Alt a 1 and dampens the human immune response, thereby supporting the notion that Alt a 1 only becomes immunogenic under nutritional deprivation.
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Affiliation(s)
- Aila Fakhimahmadi
- Comparative Medicine, The Interuniversity Messerli Research Institute, 1210 Vienna, Austria; (A.F.); (I.H.); (G.H.); (N.S.); (R.B.); (S.A.J.); (M.B.); (E.J.-J.); (K.H.)
- Institute of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Ilir Hasanaj
- Comparative Medicine, The Interuniversity Messerli Research Institute, 1210 Vienna, Austria; (A.F.); (I.H.); (G.H.); (N.S.); (R.B.); (S.A.J.); (M.B.); (E.J.-J.); (K.H.)
| | - Gerlinde Hofstetter
- Comparative Medicine, The Interuniversity Messerli Research Institute, 1210 Vienna, Austria; (A.F.); (I.H.); (G.H.); (N.S.); (R.B.); (S.A.J.); (M.B.); (E.J.-J.); (K.H.)
- Institute of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Clara Pogner
- Bioresources Unit, Center for Health & Bioresources, AIT Austrian Institute of Technology GmbH, 3430 Tulln, Austria; (C.P.); (M.G.)
| | - Markus Gorfer
- Bioresources Unit, Center for Health & Bioresources, AIT Austrian Institute of Technology GmbH, 3430 Tulln, Austria; (C.P.); (M.G.)
| | - Markus Wiederstein
- Department of Biosciences, University of Salzburg, 5020 Salzburg, Austria;
| | - Nathalie Szepannek
- Comparative Medicine, The Interuniversity Messerli Research Institute, 1210 Vienna, Austria; (A.F.); (I.H.); (G.H.); (N.S.); (R.B.); (S.A.J.); (M.B.); (E.J.-J.); (K.H.)
| | - Rodolfo Bianchini
- Comparative Medicine, The Interuniversity Messerli Research Institute, 1210 Vienna, Austria; (A.F.); (I.H.); (G.H.); (N.S.); (R.B.); (S.A.J.); (M.B.); (E.J.-J.); (K.H.)
| | - Zdenek Dvorak
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University, 779 00 Olomouc, Czech Republic;
| | - Sebastian A. Jensen
- Comparative Medicine, The Interuniversity Messerli Research Institute, 1210 Vienna, Austria; (A.F.); (I.H.); (G.H.); (N.S.); (R.B.); (S.A.J.); (M.B.); (E.J.-J.); (K.H.)
| | - Markus Berger
- Comparative Medicine, The Interuniversity Messerli Research Institute, 1210 Vienna, Austria; (A.F.); (I.H.); (G.H.); (N.S.); (R.B.); (S.A.J.); (M.B.); (E.J.-J.); (K.H.)
| | - Erika Jensen-Jarolim
- Comparative Medicine, The Interuniversity Messerli Research Institute, 1210 Vienna, Austria; (A.F.); (I.H.); (G.H.); (N.S.); (R.B.); (S.A.J.); (M.B.); (E.J.-J.); (K.H.)
- Institute of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Karin Hufnagl
- Comparative Medicine, The Interuniversity Messerli Research Institute, 1210 Vienna, Austria; (A.F.); (I.H.); (G.H.); (N.S.); (R.B.); (S.A.J.); (M.B.); (E.J.-J.); (K.H.)
- Institute of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Franziska Roth-Walter
- Comparative Medicine, The Interuniversity Messerli Research Institute, 1210 Vienna, Austria; (A.F.); (I.H.); (G.H.); (N.S.); (R.B.); (S.A.J.); (M.B.); (E.J.-J.); (K.H.)
- Institute of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria
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Roth-Walter F. Iron-Deficiency in Atopic Diseases: Innate Immune Priming by Allergens and Siderophores. Front Allergy 2022; 3:859922. [PMID: 35769558 PMCID: PMC9234869 DOI: 10.3389/falgy.2022.859922] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 03/03/2022] [Indexed: 12/12/2022] Open
Abstract
Although iron is one of the most abundant elements on earth, about a third of the world's population are affected by iron deficiency. Main drivers of iron deficiency are beside the chronic lack of dietary iron, a hampered uptake machinery as a result of immune activation. Macrophages are the principal cells distributing iron in the human body with their iron restriction skewing these cells to a more pro-inflammatory state. Consequently, iron deficiency has a pronounced impact on immune cells, favoring Th2-cell survival, immunoglobulin class switching and primes mast cells for degranulation. Iron deficiency during pregnancy increases the risk of atopic diseases in children, while both children and adults with allergy are more likely to have anemia. In contrast, an improved iron status seems to protect against allergy development. Here, the most important interconnections between iron metabolism and allergies, the effect of iron deprivation on distinct immune cell types, as well as the pathophysiology in atopic diseases are summarized. Although the main focus will be humans, we also compare them with innate defense and iron sequestration strategies of microbes, given, particularly, attention to catechol-siderophores. Similarly, the defense and nutritional strategies in plants with their inducible systemic acquired resistance by salicylic acid, which further leads to synthesis of flavonoids as well as pathogenesis-related proteins, will be elaborated as both are very important for understanding the etiology of allergic diseases. Many allergens, such as lipocalins and the pathogenesis-related proteins, are able to bind iron and either deprive or supply iron to immune cells. Thus, a locally induced iron deficiency will result in immune activation and allergic sensitization. However, the same proteins such as the whey protein beta-lactoglobulin can also transport this precious micronutrient to the host immune cells (holoBLG) and hinder their activation, promoting tolerance and protecting against allergy. Since 2019, several clinical trials have also been conducted in allergic subjects using holoBLG as a food for special medical purposes, leading to a reduction in the allergic symptom burden. Supplementation with nutrient-carrying lipocalin proteins can circumvent the mucosal block and nourish selectively immune cells, therefore representing a new dietary and causative approach to compensate for functional iron deficiency in allergy sufferers.
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Affiliation(s)
- Franziska Roth-Walter
- Comparative Medicine, The Interuniversity Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University Vienna, University of Vienna, Vienna, Austria
- Institute of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
- *Correspondence: Franziska Roth-Walter ;
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Leech SC, Ewan PW, Skypala IJ, Brathwaite N, Erlewyn-Lajeunesse M, Heath S, Ball H, James P, Murphy K, Clark AT. BSACI 2021 guideline for the management of egg allergy. Clin Exp Allergy 2021; 51:1262-1278. [PMID: 34586690 DOI: 10.1111/cea.14009] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 08/09/2021] [Accepted: 08/15/2021] [Indexed: 12/19/2022]
Abstract
This guideline advises on the management of patients with egg allergy. Most commonly egg allergy presents in infancy, with a prevalence of approximately 2% in children and 0.1% in adults. A clear clinical history will confirm the diagnosis in most cases. Investigation by measuring egg-specific IgE (by skin prick testing or specific IgE assay) is useful in moderate-severe cases or where there is diagnostic uncertainty. Following an acute allergic reaction, egg avoidance advice should be provided. Egg allergy usually resolves, and reintroduction can be achieved at home if reactions have been mild and there is no asthma. Patients with a history of severe reactions or asthma should have reintroduction guided by a specialist. All children with egg allergy should receive the MMR vaccine. Most adults and children with egg allergy can receive the influenza vaccine in primary care, unless they have had anaphylaxis to egg requiring intensive care support. Yellow Fever vaccines should only be considered in egg-allergic patients under the guidance of an allergy specialist. This guideline was prepared by the Standards of Care Committee (SOCC) of the British Society for Allergy and Clinical Immunology (BSACI) and is intended for allergists and others with a special interest in allergy. The recommendations are evidence based. Where evidence was lacking, consensus was reached by the panel of specialists on the committee. The document encompasses epidemiology, risk factors, diagnosis, treatment, prognosis and co-morbid associations.
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Affiliation(s)
- Susan C Leech
- Department of Child Health, Kings College Hospital, London, UK
| | - Pamela W Ewan
- Allergy Clinic, NHS Foundation Trust, Cambridge University, Cambridge, UK
| | | | - Nicola Brathwaite
- Department of Child Health, Kings College Hospital, London, UK.,Department of Child Health, Kings College Hospital, London, UK
| | | | - Sarah Heath
- Department of Child Health, Kings College Hospital, London, UK
| | - Heidi Ball
- University Hospitals Leicester, Leicester, UK
| | - Polly James
- Evelina Children's Hospital, Guys and St Thomas' NHS Foundation Trust, London, UK
| | - Karen Murphy
- Evelina Children's Hospital, Guys and St Thomas' NHS Foundation Trust, London, UK
| | - Andrew T Clark
- Allergy Clinic, NHS Foundation Trust, Cambridge University, Cambridge, UK
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Roth-Walter F, Pacios LF, Bianchini R, Jensen-Jarolim E. Linking iron-deficiency with allergy: role of molecular allergens and the microbiome. Metallomics 2017; 9:1676-1692. [PMID: 29120476 DOI: 10.1039/c7mt00241f] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Atopic individuals tend to develop a Th2 dominant immune response, resulting in hyperresponsiveness to harmless antigens, termed allergens. In the last decade, epidemiological studies have emerged that connected allergy with a deficient iron-status. Immune activation under iron-deficient conditions results in the expansion of Th2-, but not Th1 cells, can induce class-switching in B-cells and hampers the proper activation of M2, but not M1 macrophages. Moreover, many allergens, in particular with the lipocalin and lipocalin-like folds, seem to be capable of binding iron indirectly via siderophores harboring catechol moieties. The resulting locally restricted iron-deficiency may then lead during immune activation to the generation of Th2-cells and thus prepare for allergic sensitization. Moreover, iron-chelators seem to also influence clinical reactivity: mast cells accumulate iron before degranulation and seem to respond differently depending on the type of the encountered siderophore. Whereas deferoxamine triggers degranulation of connective tissue-type mast cells, catechol-based siderophores reduce activation and degranulation and improve clinical symptoms. Considering the complex interplay of iron, siderophores and immune molecules, it remains to be determined whether iron-deficiencies are the cause or the result of allergy.
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Affiliation(s)
- Franziska Roth-Walter
- Department of Comparative Medicine, at the Interuniversity Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, Vienna, Austria.
| | - Luis F Pacios
- Centro de Biotecnología y Genómica de Plantas (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo-UPM, 28223 Pozuelo de Alarcón, Madrid, Spain
| | - Rodolfo Bianchini
- Department of Comparative Medicine, at the Interuniversity Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, Vienna, Austria.
| | - Erika Jensen-Jarolim
- Department of Comparative Medicine, at the Interuniversity Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, Vienna, Austria. and Institute of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
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7
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Diesner SC, Schultz C, Ackaert C, Oostingh GJ, Ondracek A, Stremnitzer C, Singer J, Heiden D, Roth-Walter F, Fazekas J, Assmann VE, Jensen-Jarolim E, Stutz H, Duschl A, Untersmayr E. Nitration of β-Lactoglobulin but Not of Ovomucoid Enhances Anaphylactic Responses in Food Allergic Mice. PLoS One 2015; 10:e0126279. [PMID: 25955653 PMCID: PMC4425501 DOI: 10.1371/journal.pone.0126279] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 03/31/2015] [Indexed: 12/31/2022] Open
Abstract
Background We revealed in previous studies that nitration of food proteins reduces the risk of de novo sensitization in a murine food allergy model. In contrast, in situations with preformed specific IgE antibodies, in vitro experiments suggested an increased capacity of effector cell activation by nitrated food proteins. Objective The aim of this study was to investigate the influence of protein nitration on the effector phase of food allergy. Design BALB/c mice were immunized intraperitoneally (i.p.) with the milk allergen β-lactoglobulin (BLG) or the egg allergen ovomucoid (OVM), followed by intragastric (i.g.) gavages to induce a strong local inflammatory response and allergen-specific antibodies. Subsequently, naïve and allergic mice were intravenously (i.v.) challenged with untreated, sham-nitrated or nitrated BLG or OVM. Anaphylaxis was monitored by measuring core body temperature and determination of mouse mast cell protease-1 (mMCP-1) levels in blood. Results A significant drop of body temperature accompanied with significantly elevated concentrations of the anaphylaxis marker mMCP-1 were only observed in BLG allergic animals challenged with nitrated BLG and not in OVM allergic mice challenged with nitrated OVM. SDS-PAGE and circular dichroism analysis of the differentially modified allergens revealed an effect of nitration on the secondary protein structure exclusively for BLG together with enhanced protein aggregation. Conclusion Our data suggest that nitration affects differently the food allergens BLG and OVM. In the case of BLG, structural changes favored dimerization possibly explaining the increased anaphylactic reactivity in BLG allergic animals.
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Affiliation(s)
- Susanne C. Diesner
- Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Cornelia Schultz
- Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Chloé Ackaert
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Gertie J. Oostingh
- Biomedical Sciences, Salzburg University of Applied Sciences, Puch/Salzburg, Austria
| | - Anna Ondracek
- Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Caroline Stremnitzer
- Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Josef Singer
- Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Denise Heiden
- Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Franziska Roth-Walter
- Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
- Comparative Medicine, Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University Vienna and University Vienna, Vienna, Austria
| | - Judit Fazekas
- Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Vera E. Assmann
- Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Erika Jensen-Jarolim
- Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
- Comparative Medicine, Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University Vienna and University Vienna, Vienna, Austria
| | - Hanno Stutz
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Albert Duschl
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Eva Untersmayr
- Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
- * E-mail:
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Pahr S, Selb R, Weber M, Focke-Tejkl M, Hofer G, Dordić A, Keller W, Papadopoulos NG, Giavi S, Mäkelä M, Pelkonen A, Niederberger V, Vrtala S, Valenta R. Biochemical, biophysical and IgE-epitope characterization of the wheat food allergen, Tri a 37. PLoS One 2014; 9:e111483. [PMID: 25368998 PMCID: PMC4219751 DOI: 10.1371/journal.pone.0111483] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 10/02/2014] [Indexed: 11/24/2022] Open
Abstract
Wheat is an important staple food and potent allergen source. Recently, we isolated a cDNA coding for wheat alpha-purothionin which is recognized by wheat food allergic patients at risk for severe wheat-induced allergy. The purpose of the present study was the biochemical, biophysical and IgE epitope characterization of recombinant alpha-purothionin. Synthetic genes coding for alpha-purothionin were expressed in a prokaryotic system using Escherichia coli and in a eukaryotic expression system based on baculovirus-infected Sf9-insect cells. Recombinant proteins were purified and characterized by SDS-PAGE, mass spectrometry, circular dichroism, chemical cross-linking and size exclusion chromatography. Five overlapping peptid were synthesized for epitope mapping. Alpha-purothionin-specific rabbit antibodies were raised to perform IgE-inhibition experiments and to study the resistance to digestion. The IgE reactivity of the proteins and peptides from ten wheat food allergic patients was studied in non-denaturing RAST-based binding assays. Alpha-purothionin was expressed in the prokaryotic (EcTri a 37) and in the eukaryotic system (BvTri a 37) as a soluble and monomeric protein. However, circular dichroism analysis revealed that EcTri a 37 was unfolded whereas BvTri a 37 was a folded protein. Both proteins showed comparable IgE-reactivity and the epitope mapping revealed the presence of sequential IgE epitopes in the N-terminal basic thionin domain (peptide1:KSCCRSTLGRNCYNLCRARGAQKLCAGVCR) and in the C-terminal acidic extension domain (peptide3:KGFPKLALESNSDEPDTIEYCNLGCRSSVC, peptide4:CNLGCRSSVCDYMVNAAADDEEMKLYVEN). Natural Tri a 37 was digested under gastric conditions but resistant to duodenal digestion. Immunization with EcTri a 37 induced IgG antibodies which recognized similar epitopes as IgE antibodies from allergic patients and inhibited allergic patients' IgE binding. Reactivity to Tri a 37 does not require a folded protein and the presence of sequential IgE epitopes indicates that sensitization to alpha-purothionin occurs via the gut. Both allergens can be used for in-vitro diagnosis of wheat food allergy. The induction of blocking IgG antibodies suggests the usefulness for immunotherapy.
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Affiliation(s)
- Sandra Pahr
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for the Development of Allergen Chips, Medical University of Vienna, Vienna, Austria
| | - Regina Selb
- Department of ENT, Medical University of Vienna, Vienna, Austria
| | - Milena Weber
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Margarete Focke-Tejkl
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Gerhard Hofer
- Institute of Molecular Biosciences, Karl-Franzens University Graz, Graz, Austria
| | - Andela Dordić
- Institute of Molecular Biosciences, Karl-Franzens University Graz, Graz, Austria
| | - Walter Keller
- Institute of Molecular Biosciences, Karl-Franzens University Graz, Graz, Austria
| | | | - Stavroula Giavi
- Allergy Department, 2nd Pediatric Clinic, University of Athens, Athens, Greece
| | - Mika Mäkelä
- Skin and Allergy Hospital, Helsinki University Central Hospital, Helsinki, Finland
| | - Anna Pelkonen
- Skin and Allergy Hospital, Helsinki University Central Hospital, Helsinki, Finland
| | | | - Susanne Vrtala
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for the Development of Allergen Chips, Medical University of Vienna, Vienna, Austria
| | - Rudolf Valenta
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
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