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Gao S, Huan F, Wu MX, Ni LN, Gu Y, Liu YX, Han TJ, Liu M, Lai D, Liu GM. Mutation of Disulfide Bond Sites Reduces the Immunoreactivity of Cra a 4 by Changing the Structural Characteristics. J Agric Food Chem 2024. [PMID: 38598840 DOI: 10.1021/acs.jafc.4c01120] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
Sarcoplasmic calcium-binding protein (Cra a 4) from Crassostrea angulata belongs to the EF-hand superfamily, and understanding of its structure-allergenicity relationship is still insufficient. In this study, chemical denaturants were used to destroy the structure of Cra a 4, showing that disruption of the structure reduced its IgG-/IgE-binding activity. To explore which critical amino acid site affects the allergenicity of Cra a 4, the mutants were obtained by site-directed mutations in the disulfide bonds site (C97), conformational epitopes (I105, D114), or Ca2+-binding region (D106, D110) and their IgG-/IgE-binding activity was reduced significantly using serological tests. Notably, C97A had the lowest immunoreactivity. In addition, two conformational epitopes of Cra 4 were verified. Meanwhile, the increase of the α-helical content, surface hydrophobicity, and surface electrostatic potential of C97A affected its allergenicity. Overall, the understanding of the structure-allergenicity relationship of Cra a 4 allowed the development of a hypoallergenic mutant.
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Affiliation(s)
- Shuai Gao
- College of Ocean Food and Biological Engineering, Xiamen Key Laboratory of Marine Functional Food, Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Jimei University, Xiamen 361021, Fujian, China
| | - Fei Huan
- College of Ocean Food and Biological Engineering, Xiamen Key Laboratory of Marine Functional Food, Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Jimei University, Xiamen 361021, Fujian, China
| | - Ming-Xuan Wu
- College of Ocean Food and Biological Engineering, Xiamen Key Laboratory of Marine Functional Food, Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Jimei University, Xiamen 361021, Fujian, China
| | - Ling-Na Ni
- College of Ocean Food and Biological Engineering, Xiamen Key Laboratory of Marine Functional Food, Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Jimei University, Xiamen 361021, Fujian, China
| | - Yi Gu
- College of Ocean Food and Biological Engineering, Xiamen Key Laboratory of Marine Functional Food, Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Jimei University, Xiamen 361021, Fujian, China
| | - Ya-Xin Liu
- College of Ocean Food and Biological Engineering, Xiamen Key Laboratory of Marine Functional Food, Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Jimei University, Xiamen 361021, Fujian, China
| | - Tian-Jiao Han
- College of Ocean Food and Biological Engineering, Xiamen Key Laboratory of Marine Functional Food, Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Jimei University, Xiamen 361021, Fujian, China
| | - Meng Liu
- College of Ocean Food and Biological Engineering, Xiamen Key Laboratory of Marine Functional Food, Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Jimei University, Xiamen 361021, Fujian, China
| | - Dong Lai
- The Second Affiliated Hospital of Xiamen Medical College, Xiamen 361021, Fujian, China
| | - Guang-Ming Liu
- College of Ocean Food and Biological Engineering, Xiamen Key Laboratory of Marine Functional Food, Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Jimei University, Xiamen 361021, Fujian, China
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Hu J, Zhu LP, Wang RQ, Zhu L, Chen F, Hou Y, Ni K, Deng S, Liu S, Ying W, Sun JL, Li H, Jin T. Identification, Characterization, Cloning, and Cross-Reactivity of Zan b 2, a Novel Pepper Allergen of 11S Legumin. J Agric Food Chem 2024; 72:8189-8199. [PMID: 38551197 PMCID: PMC11010233 DOI: 10.1021/acs.jafc.4c00351] [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] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 03/11/2024] [Accepted: 03/13/2024] [Indexed: 04/11/2024]
Abstract
Protein from Sichuan peppers can elicit mild to severe allergic reactions. However, little is known about their allergenic proteins. We aimed to isolate, identify, clone, and characterize Sichuan pepper allergens and to determine its allergenicity and cross-reactivities. Sichuan pepper seed proteins were extracted and then analyzed by SDS-PAGE. Western blotting was performed with sera from Sichuan pepper-allergic individuals. Proteins of interest were purified using hydrophobic interaction chromatography and gel filtration and further analyzed by analytical ultracentrifugation, circular dichroism spectroscopy, and mass spectrometry (MS). Their coding region was amplified in the genome. IgE reactivity and cross-reactivity of allergens were evaluated by dot blot, enzyme-linked immunosorbent assay (ELISA), and competitive ELISA. Western blot showed IgE binding to a 55 kDa protein. This protein was homologous to the citrus proteins and has high stability and a sheet structure. Four DNA sequences were cloned. Six patients' sera (60%) showed specific IgE reactivity to this purified 11S protein, which was proved to have cross-reactivation with extracts of cashew nuts, pistachios, and citrus seeds. A novel allergen in Sichuan pepper seeds, Zan b 2, which belongs to the 11S globulin family, was isolated and identified. Its cross-reactivity with cashew nuts, pistachios, and citrus seeds was demonstrated.
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Affiliation(s)
- Jing Hu
- Hefei
National Laboratory for Physical Sciences at Microscale, the CAS Key
Laboratory of Innate Immunity and Chronic Disease, School of Basic
Medicine Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Li-Ping Zhu
- Allergy
Department, State Key Laboratory of Complex Severe and Rare Diseases,
Peking Union Medical College Hospital, Chinese
Academy of Medical Science and Peking Union Medical College, Beijing 100730, China
| | - Rui-qi Wang
- Allergy
Department, State Key Laboratory of Complex Severe and Rare Diseases,
Peking Union Medical College Hospital, Chinese
Academy of Medical Science and Peking Union Medical College, Beijing 100730, China
| | - Lixia Zhu
- Hefei
National Laboratory for Physical Sciences at Microscale, the CAS Key
Laboratory of Innate Immunity and Chronic Disease, School of Basic
Medicine Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Feng Chen
- Hefei
National Laboratory for Physical Sciences at Microscale, the CAS Key
Laboratory of Innate Immunity and Chronic Disease, School of Basic
Medicine Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Yibo Hou
- Allergy
Department, State Key Laboratory of Complex Severe and Rare Diseases,
Peking Union Medical College Hospital, Chinese
Academy of Medical Science and Peking Union Medical College, Beijing 100730, China
| | - Kang Ni
- Hefei
National Laboratory for Physical Sciences at Microscale, the CAS Key
Laboratory of Innate Immunity and Chronic Disease, School of Basic
Medicine Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Shasha Deng
- Hefei
National Laboratory for Physical Sciences at Microscale, the CAS Key
Laboratory of Innate Immunity and Chronic Disease, School of Basic
Medicine Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Siyu Liu
- Hefei
National Laboratory for Physical Sciences at Microscale, the CAS Key
Laboratory of Innate Immunity and Chronic Disease, School of Basic
Medicine Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Wantao Ying
- State
Key Laboratory of Medical Proteomics, Beijing Proteome Research Center,
National Center for Protein Sciences (Beijing), Beijing Institute
of Lifeomics, Beijing 102206, China
| | - Jin-Lyu Sun
- Allergy
Department, State Key Laboratory of Complex Severe and Rare Diseases,
Peking Union Medical College Hospital, Chinese
Academy of Medical Science and Peking Union Medical College, Beijing 100730, China
| | - Hong Li
- Allergy
Department, State Key Laboratory of Complex Severe and Rare Diseases,
Peking Union Medical College Hospital, Chinese
Academy of Medical Science and Peking Union Medical College, Beijing 100730, China
| | - Tengchuan Jin
- Hefei
National Laboratory for Physical Sciences at Microscale, the CAS Key
Laboratory of Innate Immunity and Chronic Disease, School of Basic
Medicine Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, China
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Pomés A, Smith SA, Chruszcz M, Mueller GA, Brackett NF, Chapman MD. Precision engineering for localization, validation, and modification of allergenic epitopes. J Allergy Clin Immunol 2024; 153:560-571. [PMID: 38181840 PMCID: PMC10939758 DOI: 10.1016/j.jaci.2023.12.017] [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: 08/31/2023] [Revised: 12/20/2023] [Accepted: 12/29/2023] [Indexed: 01/07/2024]
Abstract
The allergen-IgE interaction is essential for the genesis of allergic responses, yet investigation of the molecular basis of these interactions is in its infancy. Precision engineering has unveiled the molecular features of allergen-antibody interactions at the atomic level. High-resolution technologies, including x-ray crystallography, nuclear magnetic resonance spectroscopy, and cryo-electron microscopy, determine allergen-antibody structures. X-ray crystallography of an allergen-antibody complex localizes in detail amino acid residues and interactions that define the epitope-paratope interface. Multiple structures involving murine IgG mAbs have recently been resolved. The number of amino acids forming the epitope broadly correlates with the epitope area. The production of human IgE mAbs from B cells of allergic subjects is an exciting recent development that has for the first time enabled an actual IgE epitope to be defined. The biologic activity of defined IgE epitopes can be validated in vivo in animal models or by measuring mediator release from engineered basophilic cell lines. Finally, gene-editing approaches using the Clustered Regularly Interspaced Short Palindromic Repeats technology to either remove allergen genes or make targeted epitope engineering at the source are on the horizon. This review presents an overview of the identification and validation of allergenic epitopes by precision engineering.
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Affiliation(s)
| | - Scott A Smith
- Vanderbilt University Medical Center, Nashville, Tenn
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Yan Y, Li L, Long C, Dong Y, Li J, Shen C, Zhao Y, Zhao J, Wang J, Xiong A, Li X, Chen H, He S. A novel IgE epitope-specific antibodies-based sandwich ELISA for sensitive measurement of immunoreactivity changes of peanut allergen Ara h 2 in processed foods. Front Nutr 2024; 11:1323553. [PMID: 38439921 PMCID: PMC10910080 DOI: 10.3389/fnut.2024.1323553] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 02/05/2024] [Indexed: 03/06/2024] Open
Abstract
Background Peanut is an important source of dietary protein for human beings, but it is also recognized as one of the eight major food allergens. Binding of IgE antibodies to specific epitopes in peanut allergens plays important roles in initiating peanut-allergic reactions, and Ara h 2 is widely considered as the most potent peanut allergen and the best predictor of peanut allergy. Therefore, Ara h 2 IgE epitopes can serve as useful biomarkers for prediction of IgE-binding variations of Ara h 2 and peanut in foods. This study aimed to develop and validate an IgE epitope-specific antibodies (IgE-EsAbs)-based sandwich ELISA (sELISA) for detection of Ara h 2 and measurement of Ara h 2 IgE-immunoreactivity changes in foods. Methods DEAE-Sepharose Fast Flow anion-exchange chromatography combining with SDS-PAGE gel extraction were applied to purify Ara h 2 from raw peanut. Hybridoma and epitope vaccine techniques were employed to generate a monoclonal antibody against a major IgE epitope of Ara h 2 and a polyclonal antibody against 12 IgE epitopes of Ara h 2, respectively. ELISA was carried out to evaluate the target binding and specificity of the generated IgE-EsAbs. Subsequently, IgE-EsAbs-based sELISA was developed to detect Ara h 2 and its allergenic residues in food samples. The IgE-binding capacity of Ara h 2 and peanut in foods was determined by competitive ELISA. The dose-effect relationship between the Ara h 2 IgE epitope content and Ara h 2 (or peanut) IgE-binding ability was further established to validate the reliability of the developed sELISA in measuring IgE-binding variations of Ara h 2 and peanut in foods. Results The obtained Ara h 2 had a purity of 94.44%. Antibody characterization revealed that the IgE-EsAbs recognized the target IgE epitope(s) of Ara h 2 and exhibited high specificity. Accordingly, an IgE-EsAbs-based sELISA using these antibodies was able to detect Ara h 2 and its allergenic residues in food samples, with high sensitivity (a limit of detection of 0.98 ng/mL), accuracy (a mean bias of 0.88%), precision (relative standard deviation < 16.50%), specificity, and recovery (an average recovery of 98.28%). Moreover, the developed sELISA could predict IgE-binding variations of Ara h 2 and peanut in foods, as verified by using sera IgE derived from peanut-allergic individuals. Conclusion This novel immunoassay could be a user-friendly method to monitor low level of Ara h 2 and to preliminary predict in vitro potential allergenicity of Ara h 2 and peanut in processed foods.
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Affiliation(s)
- Yan Yan
- School of Public Health and Health Management, Gannan Medical University, Ganzhou, China
| | - Liming Li
- Department of Dermatology, First Affiliated Hospital of Gannan Medical University, Ganzhou, China
| | - Caiyun Long
- Department of Laboratory, Ganzhou Center for Disease Control and Prevention, Ganzhou, China
| | - Yaping Dong
- School of Public Health and Health Management, Gannan Medical University, Ganzhou, China
| | - Jinyu Li
- Department of Dermatology, First Affiliated Hospital of Gannan Medical University, Ganzhou, China
| | - Caiyi Shen
- School of Public Health and Health Management, Gannan Medical University, Ganzhou, China
| | - Yiqian Zhao
- School of Public Health and Health Management, Gannan Medical University, Ganzhou, China
| | - Jiangqiang Zhao
- School of Public Health and Health Management, Gannan Medical University, Ganzhou, China
| | - Jianbin Wang
- School of Public Health and Health Management, Gannan Medical University, Ganzhou, China
| | - Anqi Xiong
- School of Public Health and Health Management, Gannan Medical University, Ganzhou, China
| | - Xin Li
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang, China
| | - Hongbing Chen
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang, China
| | - Shengfa He
- School of Public Health and Health Management, Gannan Medical University, Ganzhou, China
- Key Laboratory of Environment and Health of Ganzhou, Gannan Medical University, Ganzhou, China
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Zhang Y, Che H, Li C, Jin T. Food Allergens of Plant Origin. Foods 2023; 12:foods12112232. [PMID: 37297475 DOI: 10.3390/foods12112232] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/24/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
This review presents an update on the physical, chemical, and biological properties of food allergens in plant sources, focusing on the few protein families that contribute to multiple food allergens from different species and protein families recently found to contain food allergens. The structures and structural components of the food allergens in the allergen families may provide further directions for discovering new food allergens. Answers as to what makes some food proteins allergens are still elusive. Factors to be considered in mitigating food allergens include the abundance of the protein in a food, the property of short stretches of the sequence of the protein that may constitute linear IgE binding epitopes, the structural properties of the protein, its stability to heat and digestion, the food matrix the protein is in, and the antimicrobial activity to the microbial flora of the human gastrointestinal tract. Additionally, recent data suggest that widely used techniques for mapping linear IgE binding epitopes need to be improved by incorporating positive controls, and methodologies for mapping conformational IgE binding epitopes need to be developed.
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Affiliation(s)
- Yuzhu Zhang
- US Department of Agriculture, Agricultural Research Service, Pacific West Area, Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710, USA
| | - Huilian Che
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Caiming Li
- US Department of Agriculture, Agricultural Research Service, Pacific West Area, Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710, USA
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi 214122, China
| | - Tengchuan Jin
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China
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