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Jacquet A, Soh WT. Spatiotemporal proteolytic susceptibility of allergens: positive or negative effects on the allergic sensitization? FRONTIERS IN ALLERGY 2024; 5:1426816. [PMID: 39044859 PMCID: PMC11263110 DOI: 10.3389/falgy.2024.1426816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 06/21/2024] [Indexed: 07/25/2024] Open
Abstract
From their expression in their respective allergenic source to their processing by antigen presenting cells, allergens continuously encounter proteases. The ability of allergens to resist to proteolysis by digestive enzymes or host-cell/microbial proteases is considered as an important property that influences their allergenic potential. However, the relationship between proteolytic stability and allergenicity is much more complex and depends on various factors, such as the protein structure dynamics, the exposure level, the route of sensitization, and their respective protease susceptibility. In this review, we summarize and discuss the current knowledge on several aspects of allergen proteolytic stability in different environments including the allergenic sources, routes of sensitization (skin, respiratory tract, gastrointestinal tract) and endolysosomal compartment of antigen-presenting cells. Proteolytic stability alone cannot represent a definitive criterion to allergenicity. The proteolytic susceptibility of allergens in processed extracts can affect allergy diagnosis and immunotherapy. Furthermore, the fine tuning of allergen stability during antigen processing can be exploited for the development of novel immunotherapeutic strategies.
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Affiliation(s)
- Alain Jacquet
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Wai Tuck Soh
- Research Group of Quantitative and Systems Biology, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
- Faculty of Applied Sciences, UCSI University, Kuala Lumpur, Malaysia
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2
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Koppelman SJ, de Jong GAH, Marsh J, Johnson P, Dowell E, Perusko M, Westphal A, van Hage M, Baumert J, Apostolovic D. Novel post-translationally cleaved Ara h 2 proteoforms: Purification, characterization and IgE-binding properties. Int J Biol Macromol 2024; 264:130613. [PMID: 38447836 DOI: 10.1016/j.ijbiomac.2024.130613] [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: 01/15/2024] [Revised: 03/01/2024] [Accepted: 03/02/2024] [Indexed: 03/08/2024]
Abstract
The 2S albumins Ara h 2 and Ara h 6 have been shown to be the most important source of allergenicity in peanut. Several isoforms of these allergens have been described. Using extraction and liquid chromatography we isolated proteins with homology to Ara h 2 and characterized hitherto unknown Ara h 2 proteoforms with additional post-translational cleavage. High-resolution mass spectrometry located the cleavage site on the non-structured loop of Ara h 2 while far UV CD spectroscopy showed a comparable structure to Ara h 2. The cleaved forms of Ara h 2 were present in genotypes of peanut commonly consumed. Importantly, we revealed that newly identified Ara h 2 cleaved proteoforms showed comparable IgE-binding using sera from 28 peanut-sensitized individuals, possessed almost the same IgE binding potency and are likely similarly allergenic as intact Ara h 2. This makes these newly identified forms relevant proteoforms of peanut allergen Ara h 2.
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Affiliation(s)
- Stef J Koppelman
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska, 279 Food Innovation Center, Lincoln, NE 68588-6207, USA
| | | | - Justin Marsh
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska, 279 Food Innovation Center, Lincoln, NE 68588-6207, USA
| | - Phil Johnson
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska, 279 Food Innovation Center, Lincoln, NE 68588-6207, USA
| | - Emily Dowell
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska, 279 Food Innovation Center, Lincoln, NE 68588-6207, USA
| | - Marija Perusko
- Division of Immunology and Allergy, Department of Medicine Solna, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden; Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Adrie Westphal
- Wageningen University and Research (WUR), Wageningen, the Netherlands
| | - Marianne van Hage
- Division of Immunology and Allergy, Department of Medicine Solna, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden; Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Joseph Baumert
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska, 279 Food Innovation Center, Lincoln, NE 68588-6207, USA
| | - Danijela Apostolovic
- Division of Immunology and Allergy, Department of Medicine Solna, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden; Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.
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3
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Zhang Y, Geng Q, Song M, Li X, Yang A, Tong P, Wu Z, Chen H. The structure and potential allergenicity of peanut allergen monomers after roasting. Food Funct 2024; 15:2577-2586. [PMID: 38353700 DOI: 10.1039/d3fo05351b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
Given that roasted peanut (Ro) products are commonly used in daily life, peanut allergenicity is a foremost concern. Analyzing the changes in the structure and potential allergenicity of individual allergens can promote the exploration of the structural basis of the alterations in the potential allergenicity of Ro. This work focused on four major allergens in raw peanut (Ra) and Ro. Structural changes were analyzed on the basis of circular dichroism, ultraviolet and fluorescence spectroscopy, and molecular dynamic simulation. The IgE recognition capability of allergens was assessed via western blot analysis. The IgE binding capacity of allergens was detected by conducting enzyme-linked immunosorbent assay. The potential allergenicity of allergens was evaluated using the KU812 cell degranulation model. The results showed that roasting induced different changes in the overall structures of allergens and altered the structures and electrostatic potential of IgE epitopes, especially Ara h 1 and Ara h 6. These alterations affected the potential allergenicity of allergens. Ara h 1 and Ara h 6 in Ro showed significantly enhanced IgE binding capacities and abilities to elicit KU812 cell degranulation, while Ara h 2 and Ara h 3 did not change significantly. For total protein, the roasted peanut protein showed decreased abilities to elicit KU812 cell degranulation. The results indicated that different allergens in Ro showed different changes of structures and potential allergenicity and that the conformational structure plays a crucial role in potential allergenicity of allergens.
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Affiliation(s)
- Ying Zhang
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, China.
- College of Food Science and Technology, Nanchang University, Nanchang, 330031, China
| | - Qin Geng
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, China.
- College of Food Science and Technology, Nanchang University, Nanchang, 330031, China
| | - Min Song
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, China.
- College of Food Science and Technology, Nanchang University, Nanchang, 330031, China
| | - Xin Li
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, China.
- College of Food Science and Technology, Nanchang University, Nanchang, 330031, China
| | - Anshu Yang
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, China.
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
| | - Ping Tong
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, China.
- College of Food Science and Technology, Nanchang University, Nanchang, 330031, China
| | - Zhihua Wu
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, China.
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
| | - Hongbing Chen
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, China.
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
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4
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Marsh JT, Palmer LK, Koppelman SJ, Johnson PE. Determination of Allergen Levels, Isoforms, and Their Hydroxyproline Modifications Among Peanut Genotypes by Mass Spectrometry. FRONTIERS IN ALLERGY 2022; 3:872714. [PMID: 35769555 PMCID: PMC9234871 DOI: 10.3389/falgy.2022.872714] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 04/12/2022] [Indexed: 11/13/2022] Open
Abstract
The recently published reference genome of peanuts enables a detailed molecular description of the allergenic proteins of the seed. We used LC-MS/MS to investigate peanuts of different genotypes to assess variability and to better describe naturally occurring allergens and isoforms. Using relative quantification by mass spectrometry, minor variation of some allergenic proteins was observed, but total levels of Ara h 1, 2, 3, and 6 were relatively consistent among 20 genotypes. Previously published RP-HPLC methodology was used for comparison. The abundance of three Ara h 3 isoforms were variable among the genotypes and contributed to a large proportion of total Ara h 3 where present. Previously unpublished hydroxyproline sites were identified in Ara h 1 and 3. Hydroxylation did not vary significantly where sites were present. Peanut allergen composition was largely stable, with only some isoforms displaying differences between genotypes. The resulting differences in allergenicity are of unknown clinical significance but are likely to be minor. The data presented herein allow for the design of targeted MS methodology to allow the quantitation and therefore control of peanut allergens of clinical relevance and observed variability.
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Apostolovic D, Marsh JT, Baumert J, Taylor SL, Westphal A, de Jongh H, Johnson P, de Jong GAH, Koppelman SJ. Purification and Initial Characterization of Ara h 7, a Peanut Allergen from the 2S Albumin Protein Family. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:6318-6329. [PMID: 34037388 DOI: 10.1021/acs.jafc.1c00618] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
2S albumins are important peanut allergens. Within this protein family, Ara h 2 and Ara h 6 have been described in detail, but Ara h 7 has received little attention. We now describe the first purification of Ara h 7 and its characterization. Two Ara h 7 isoforms were purified from peanuts. Mass spectrometry revealed that both the isoforms have a post-translation cleavage, a hydroxyproline modification near the N-terminus, and four disulfide bonds. The secondary structure of both Ara h 7 isoforms is highly comparable to those of Ara h 2 and Ara h 6. Both Ara h 7 isoforms bind IgE, and Ara h 7 is capable of inhibiting the binding between Ara h 2 and IgE, suggesting at least partially cross-reactive IgE epitopes. Ara h 7 was found in all main market types of peanut, at comparable levels. This suggests that Ara h 7 is a relevant allergen from the peanut 2S albumin protein family.
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Affiliation(s)
- Danijela Apostolovic
- Immunology and Allergy Division, Department of Medicine Solna, Karolinska Institutet, Solnavägen 1, 171 77 Solna, Sweden
| | - Justin T Marsh
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska, 279 Food Innovation Center, Lincoln, Nebraska 68588-6207, United States
| | - Joe Baumert
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska, 279 Food Innovation Center, Lincoln, Nebraska 68588-6207, United States
| | - Steve L Taylor
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska, 279 Food Innovation Center, Lincoln, Nebraska 68588-6207, United States
| | - Adrie Westphal
- Biochemistry Dept., Wageningen University and Research, PO Box 17, 6700 AA Wageningen, The Netherlands
| | - Harmen de Jongh
- ProtinConsult, Rozenstraat 19, 3702 VL Zeist, The Netherlands
| | - Phil Johnson
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska, 279 Food Innovation Center, Lincoln, Nebraska 68588-6207, United States
| | - Govardus A H de Jong
- Wageningen University and Research, Food and Biobased Research. PO Box 17, 6700 AA Wageningen, The Netherlands
| | - Stef J Koppelman
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska, 279 Food Innovation Center, Lincoln, Nebraska 68588-6207, United States
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6
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Dreskin SC, Koppelman SJ, Andorf S, Nadeau KC, Kalra A, Braun W, Negi SS, Chen X, Schein CH. The importance of the 2S albumins for allergenicity and cross-reactivity of peanuts, tree nuts, and sesame seeds. J Allergy Clin Immunol 2021; 147:1154-1163. [PMID: 33217410 PMCID: PMC8035160 DOI: 10.1016/j.jaci.2020.11.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 11/06/2020] [Accepted: 11/10/2020] [Indexed: 12/17/2022]
Abstract
Allergies to peanuts, tree nuts, and sesame seeds are among the most important food-related causes of anaphylaxis. Important clinical questions include: Why is there a variable occurrence of coallergy among these foods and Is this immunologically mediated? The clinical and immunologic data summarized here suggest an immunologic basis for these coallergies that is based on similarities among the 2S albumins. Data from component resolved diagnostics have highlighted the relationship between IgE binding to these allergens and the presence of IgE-mediated food allergy. Furthermore, in vitro and in vivo experiments provide strong evidence that the 2S albumins are the most important allergens in peanuts for inducing an allergic effector response. Although the 2S albumins are diverse, they have a common disulfide-linked core with similar physicochemical properties that make them prime candidates to explain much of the observed coallergy among peanuts, tree nuts, and sesame seeds. The well-established frequency of cashew and pistachio nut coallergy (64%-100%) highlights how the structural similarities among their 2S albumins may account for observed clinical cross-reactivity. A complete understanding of the physicochemical properties of the 2S albumins in peanuts, tree nuts, and sesame seeds will enhance our ability to diagnose, treat, and ultimately prevent these allergies.
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Affiliation(s)
- Stephen C Dreskin
- Division of Allergy and Clinical Immunology, Department of Medicine, University of Colorado Denver, Aurora, Colo.
| | - Stef J Koppelman
- Food Allergy Research and Resource Program, Department of Food Science and Technology, University of Nebraska, Lincoln, Neb
| | - Sandra Andorf
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio; Sean N. Parker Center for Allergy and Asthma Research, Stanford University School of Medicine, Stanford, Calif
| | - Kari C Nadeau
- Sean N. Parker Center for Allergy and Asthma Research, Stanford University School of Medicine, Stanford, Calif
| | - Anjeli Kalra
- Division of Allergy and Clinical Immunology, Department of Medicine, University of Colorado Denver, Aurora, Colo
| | - Werner Braun
- Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, Tex; Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Tex
| | - Surendra S Negi
- Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, Tex; Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Tex
| | - Xueni Chen
- Division of Allergy and Clinical Immunology, Department of Medicine, University of Colorado Denver, Aurora, Colo
| | - Catherine H Schein
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Tex; Institute for Human Infection and Immunity, The University of Texas Medical Branch, Galveston, Tex.
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7
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Czolk R, Klueber J, Sørensen M, Wilmes P, Codreanu-Morel F, Skov PS, Hilger C, Bindslev-Jensen C, Ollert M, Kuehn A. IgE-Mediated Peanut Allergy: Current and Novel Predictive Biomarkers for Clinical Phenotypes Using Multi-Omics Approaches. Front Immunol 2021; 11:594350. [PMID: 33584660 PMCID: PMC7876438 DOI: 10.3389/fimmu.2020.594350] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 12/11/2020] [Indexed: 01/22/2023] Open
Abstract
Food allergy is a collective term for several immune-mediated responses to food. IgE-mediated food allergy is the best-known subtype. The patients present with a marked diversity of clinical profiles including symptomatic manifestations, threshold reactivity and reaction kinetics. In-vitro predictors of these clinical phenotypes are evasive and considered as knowledge gaps in food allergy diagnosis and risk management. Peanut allergy is a relevant disease model where pioneer discoveries were made in diagnosis, immunotherapy and prevention. This review provides an overview on the immune basis for phenotype variations in peanut-allergic individuals, in the light of future patient stratification along emerging omic-areas. Beyond specific IgE-signatures and basophil reactivity profiles with established correlation to clinical outcome, allergenomics, mass spectrometric resolution of peripheral allergen tracing, might be a fundamental approach to understand disease pathophysiology underlying biomarker discovery. Deep immune phenotyping is thought to reveal differential cell responses but also, gene expression and gene methylation profiles (eg, peanut severity genes) are promising areas for biomarker research. Finally, the study of microbiome-host interactions with a focus on the immune system modulation might hold the key to understand tissue-specific responses and symptoms. The immune mechanism underlying acute food-allergic events remains elusive until today. Deciphering this immunological response shall enable to identify novel biomarker for stratification of patients into reaction endotypes. The availability of powerful multi-omics technologies, together with integrated data analysis, network-based approaches and unbiased machine learning holds out the prospect of providing clinically useful biomarkers or biomarker signatures being predictive for reaction phenotypes.
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Affiliation(s)
- Rebecca Czolk
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
- Faculty of Science, Technology and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Julia Klueber
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
- Department of Dermatology and Allergy Center, Odense Research Center for Anaphylaxis, University of Southern Denmark, Odense, Denmark
| | - Martin Sørensen
- Department of Pediatric and Adolescent Medicine, University Hospital of North Norway, Tromsø, Norway
- Pediatric Research Group, Department of Clinical Medicine, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Paul Wilmes
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Françoise Codreanu-Morel
- Department of Allergology and Immunology, Centre Hospitalier de Luxembourg-Kanner Klinik, Luxembourg, Luxembourg
| | - Per Stahl Skov
- Department of Dermatology and Allergy Center, Odense Research Center for Anaphylaxis, University of Southern Denmark, Odense, Denmark
- RefLab ApS, Copenhagen, Denmark
- Institute of Immunology, National University of Copenhagen, Copenhagen, Denmark
| | - Christiane Hilger
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
| | - Carsten Bindslev-Jensen
- Department of Dermatology and Allergy Center, Odense Research Center for Anaphylaxis, University of Southern Denmark, Odense, Denmark
| | - Markus Ollert
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
- Department of Dermatology and Allergy Center, Odense Research Center for Anaphylaxis, University of Southern Denmark, Odense, Denmark
| | - Annette Kuehn
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
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8
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Pilolli R, Van Poucke C, De Angelis E, Nitride C, de Loose M, Gillard N, Huet AC, Tranquet O, Larré C, Adel-Patient K, Bernard H, Mills ENC, Monaci L. Discovery based high resolution MS/MS analysis for selection of allergen markers in chocolate and broth powder matrices. Food Chem 2020; 343:128533. [PMID: 33183874 DOI: 10.1016/j.foodchem.2020.128533] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 10/19/2020] [Accepted: 10/29/2020] [Indexed: 12/12/2022]
Abstract
Peptide marker identification is an important step in development of a mass spectrometry method for multiple allergen detection, since specificity, robustness and sensitivity of the overall analytical method will depend on the reliability of the proteotypic peptides. As part of the development of a multi-analyte reference method, discovery analysis of two incurred food matrices has been undertaken to select the most reliable peptide markers. Six allergenic ingredients (milk, egg, peanut, soybean, hazelnut, and almond) were incurred into either chocolate or broth powder matrix. Different conditions of protein extraction and purification were tested and the tryptic peptide pools were analysed by untargeted high resolution tandem mass spectrometry and the resulting fragmentation spectra were processed via a commercial software for sequence identification. The analysis performed on incurred foods provides both a prototype effective and straightforward sample preparation protocol and delivers reliable peptides to be included in a standardized selected reaction monitoring method.
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Affiliation(s)
- Rosa Pilolli
- Institute of Sciences of Food Production, CNR-ISPA, Bari, Italy
| | - Christof Van Poucke
- Flanders Research Institute for Agriculture, Fisheries and Food, Melle, Belgium
| | | | - Chiara Nitride
- School of Biological Sciences, Division of Infection, Immunity and Respiratory Medicine, Manchester Academic Health Science Centre, Manchester Institute of Biotechnology, The University of Manchester, UK
| | - Marc de Loose
- Flanders Research Institute for Agriculture, Fisheries and Food, Melle, Belgium
| | | | | | | | | | - Karine Adel-Patient
- INRA-CEA, Service de Pharmacologie et d'Immunoanalyse, Laboratoire d'Immuno-Allergie Alimentaire, Gif-sur-Yvette, France
| | - Hervé Bernard
- INRA-CEA, Service de Pharmacologie et d'Immunoanalyse, Laboratoire d'Immuno-Allergie Alimentaire, Gif-sur-Yvette, France
| | - E N Clare Mills
- School of Biological Sciences, Division of Infection, Immunity and Respiratory Medicine, Manchester Academic Health Science Centre, Manchester Institute of Biotechnology, The University of Manchester, UK
| | - Linda Monaci
- Institute of Sciences of Food Production, CNR-ISPA, Bari, Italy.
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9
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Nesbit JB, Schein CH, Braun BA, Gipson SAY, Cheng H, Hurlburt BK, Maleki SJ. Epitopes with similar physicochemical properties contribute to cross reactivity between peanut and tree nuts. Mol Immunol 2020; 122:223-231. [PMID: 32442779 DOI: 10.1016/j.molimm.2020.03.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 02/11/2020] [Accepted: 03/26/2020] [Indexed: 12/28/2022]
Abstract
Many individuals with peanut (PN) allergy have severe reactions to tree nuts (TN) such as walnuts or cashews. Although allergenic proteins in TN and PN have overall low identity, they share discrete sequences similar in physicochemical properties (PCP) to known IgE epitopes. Here, PCP-consensus peptides (cp, 13 aa and 31 aa) were identified from an alignment of epitope rich regions of walnut vicilin, Jug r 2, leader sequence (J2LS) and cross-reactive epitopes in the 2S albumins of peanut and synthesized. A peptide similarity search in the Structural Database of Allergenic Proteins (SDAP) revealed a network of peptides similar (low property distance, PD) to the 13 aa cp (13cp) in many different plant allergens. Peptides similar to the 13cp in PN and TN allergens bound IgE from sera of patients allergic to PN and TN in peptide microarray analysis. The 13cp was used to produce a rabbit consensus peptide antibody (cpAB) that detected proteins containing repeats similar to the 13cp in western blots of various nut extracts, in which reactive proteins were identified by mass spectrometry. The cpAB bound more specifically to allergens and nut extracts containing multiple repeats similar to the 13 cp, such as almond (Pru du 6), peanut (Ara h 2) and walnut (Jug r 2). IgE binding to various nut extracts is inhibited by recombinant J2LS sequence and synthetic 31cp. Thus, several repeated sequences similar to the 13cp are bound by IgE. Multiple similar repeats in several allergens could account for reaction severity and clinically relevant cross-reactivity to PN and TN. These findings may help improve detection, diagnostic, and therapeutic tools.
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Affiliation(s)
- Jacqueline B Nesbit
- Dept of Agriculture-Agricultural Research Service-Southern Regional Research Center (USDA-ARS-SRRC), New Orleans, LA, United States
| | - Catherine H Schein
- Department of Biochemistry and Molecular Biology, Institute for Human Infection and Immunity, University of Texas Medical Branch at Galveston (UTMB), TX, United States.
| | - Benjamin A Braun
- Department of Computer Science, Stanford University, United States
| | - Stephen A Y Gipson
- Dept of Agriculture-Agricultural Research Service-Southern Regional Research Center (USDA-ARS-SRRC), New Orleans, LA, United States
| | - Hsiaopo Cheng
- Dept of Agriculture-Agricultural Research Service-Southern Regional Research Center (USDA-ARS-SRRC), New Orleans, LA, United States
| | - Barry K Hurlburt
- Dept of Agriculture-Agricultural Research Service-Southern Regional Research Center (USDA-ARS-SRRC), New Orleans, LA, United States
| | - Soheila J Maleki
- Dept of Agriculture-Agricultural Research Service-Southern Regional Research Center (USDA-ARS-SRRC), New Orleans, LA, United States.
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10
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de Jongh HHJ, de Jong GAH, Apostolovic D, Taylor SL, Baumert JL, Koppelman SJ. Effect of heat treatment on the conformational stability of intact and cleaved forms ofthe peanut allergen Ara h 6 in relation to its IgE-binding potency. Food Chem 2020; 326:127027. [PMID: 32438232 DOI: 10.1016/j.foodchem.2020.127027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/16/2020] [Accepted: 05/08/2020] [Indexed: 01/14/2023]
Abstract
This work reports on theeffect of heat treatment on the protein conformational stabilityof intact and post-translationallycleaved peanut allergen Ara h 6 in relation to IgE-binding. Intact and post-translationallycleaved Ara h 6 are structurally similar and theirstrong resistance to denaturant-inducedunfolding is comparable. Only upon exposure toautoclave conditions the twoforms of Ara h 6 demonstrated susceptibility toirreversible denaturationresulting in a significant decrease in IgE-binding potency. Thisreduction isfor the intact protein more pronounced than for than for the cleaved form. This isattributed to less conformational constrains of the cleaved form comparedtointact, as suggested by the 2-fold lower activation energy for unfoldingfound for the cleavedform. Overall, harsh conditionsare required to denature Ara h 6 and to significantly reduce its IgE-bindingpotency. The cleavedform possesses more resistance to such denaturation than the intactform.
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Affiliation(s)
| | | | - Danijela Apostolovic
- Clinical Immunology and Allergy Unit, Department of Medicine Solna, Karolinska Institutet, Solnavägen 1, 171 77 Solna, Sweden
| | - Steve L Taylor
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska, 279 Food Innovation Center, Lincoln, NE 68588-6207, USA
| | - Joseph L Baumert
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska, 279 Food Innovation Center, Lincoln, NE 68588-6207, USA
| | - Stef J Koppelman
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska, 279 Food Innovation Center, Lincoln, NE 68588-6207, USA.
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