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Hu W, Xiong Z, Meng X, Wu Y, Tong P, Gao J, Li X, Chen H. Lipid matrix-specific pretreatment method for enhancing the extractability and allergenicity maintenance of bovine milk allergens in ELISA detection. Food Chem 2024; 452:139462. [PMID: 38723563 DOI: 10.1016/j.foodchem.2024.139462] [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: 02/01/2024] [Revised: 04/21/2024] [Accepted: 04/21/2024] [Indexed: 06/01/2024]
Abstract
The presence of various components in the food matrix makes allergen detection difficult and inaccurate, and pretreatment is an innovative breakthrough point. Food matrices were categorised based on their composition. Subsequently, a pretreatment method was established using a combination of ultrasound-assisted n-hexane degreasing and weakly alkaline extraction systems to enhance the detection accuracy of bovine milk allergens. Results showed that more allergens were obtained with less structural destruction, as demonstrated using immunological quantification and spectral analysis. Concurrently, allergenicity preservation was confirmed through liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, a KU812 cell degranulation model, and western blotting. The method exhibited good accuracy (bias, 8.47%), repeatability (RSDr, 1.52%), and stability (RSDR, 5.65%). In foods with high lipid content, such as chocolate, the allergen content was 2.29-fold higher than that of commercial kits. Laser confocal scanning microscopy (LCSM) and scanning electron microscopy (SEM) analyses revealed a significant decrease in fat content after post-pretreatment using our method. In addition, colloidal stability surpassed that achieved using commercial kits, as indicated through the PSA and zeta potential results. The results demonstrated the superiority of the extractability and allergenicity maintenance of lipid matrix-specific pretreatment methods for improving the accuracy of ELISA based allergen detection in real food.
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Affiliation(s)
- Wei Hu
- State Key Laboratory of Food Science and Resource, Nanchang University, Nanchang 330047, China; School of Food Science and Technology, Nanchang University, Nanchang 330031, China; Jiangxi Province Key Laboratory of Food Allergy, Nanchang 330047, China
| | - Ziyi Xiong
- State Key Laboratory of Food Science and Resource, Nanchang University, Nanchang 330047, China; School of Food Science and Technology, Nanchang University, Nanchang 330031, China; Jiangxi Province Key Laboratory of Food Allergy, Nanchang 330047, China
| | - Xuanyi Meng
- State Key Laboratory of Food Science and Resource, Nanchang University, Nanchang 330047, China; Jiangxi Province Key Laboratory of Food Allergy, Nanchang 330047, China; Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
| | - Yong Wu
- State Key Laboratory of Food Science and Resource, Nanchang University, Nanchang 330047, China; Jiangxi Province Key Laboratory of Food Allergy, Nanchang 330047, China; Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
| | - Ping Tong
- State Key Laboratory of Food Science and Resource, Nanchang University, Nanchang 330047, China; School of Food Science and Technology, Nanchang University, Nanchang 330031, China; Jiangxi Province Key Laboratory of Food Allergy, Nanchang 330047, China
| | - Jinyan Gao
- School of Food Science and Technology, Nanchang University, Nanchang 330031, China; Jiangxi Province Key Laboratory of Food Allergy, Nanchang 330047, China
| | - Xin Li
- State Key Laboratory of Food Science and Resource, Nanchang University, Nanchang 330047, China; School of Food Science and Technology, Nanchang University, Nanchang 330031, China; Jiangxi Province Key Laboratory of Food Allergy, Nanchang 330047, China.
| | - Hongbing Chen
- State Key Laboratory of Food Science and Resource, Nanchang University, Nanchang 330047, China; Jiangxi Province Key Laboratory of Food Allergy, Nanchang 330047, China; Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
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Sivill S, Iborra S, Cantillo JF. Efficient experimental method for purifying allergens from aqueous extracts. Methods 2024; 229:63-70. [PMID: 38917960 DOI: 10.1016/j.ymeth.2024.06.008] [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: 03/18/2024] [Revised: 06/13/2024] [Accepted: 06/17/2024] [Indexed: 06/27/2024] Open
Abstract
Studying the molecular and immunological basis of allergic diseases often requires purified native allergens. The methodologies for protein purification are usually difficult and may not be completely successful. The objective of this work was to describe a methodology to purify allergens from their natural source, while maintaining their native form. The purification strategy consists of a three-step protocol and was used for purifying five specific allergens, Ole e 1, Amb a 1, Alt a 1, Bet v 1 and Cup a 1. Total proteins were extracted in PBS (pH 7.2). Then, the target allergens were pre-purified and enriched by salting-out using increasing concentrations of ammonium sulfate. The allergens were further purified by anion exchange chromatography. Purification of Amb a 1 required an extra step of cation exchange chromatography. The detection of the allergens in the fractions obtained were screened by SDS-PAGE, and Western blot when needed. Further characterization of purified Amb a 1 was performed by mass spectrometry. Ole e 1, Alt a 1, Bet v 1 and Cup a 1 were obtained at > 90 % purity. Amb a 1 was obtained at > 85 % purity. Overall, we propose an easy-to-perform purification approach that allows obtaining highly pure allergens. Since it does not involve neither chaotropic nor organic reagents, we anticipate that the structural and biological functions of the purified molecule remain intact. This method provides a basis for native allergen purification that can be tailored according to specific needs.
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Affiliation(s)
- S Sivill
- R&D, Inmunotek, Alcalá de Henares, Madrid, Spain
| | - S Iborra
- R&D, Inmunotek, Alcalá de Henares, Madrid, Spain
| | - J F Cantillo
- R&D, Inmunotek, Alcalá de Henares, Madrid, Spain.
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Han X, He X, Wang X, Luo L, Li Y, Lai D, Liu H, Liu J, Rao S, Liu G. Comparative analysis of tropomyosin allergenicity in three different species of molluscs: insights into the role of amino acid composition in IgE epitopes. Food Funct 2024; 15:5397-5413. [PMID: 38639426 DOI: 10.1039/d4fo00958d] [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: 04/20/2024]
Abstract
Limited research has been conducted on the differences in allergenicity among Alectryonella plicatula tropomyosin (ATM), Haliotis discus hannai tropomyosin (HTM), and Mimachlamys nobilis tropomyosin (MTM) in molluscs. Our study aimed to comprehensively analyze and compare their immunoreactivity, sensitization, and allergenicity while simultaneously elucidating the underlying molecular mechanisms involved. We assessed the immune binding activity of TM utilizing 86 sera from allergic patients and evaluated sensitization and allergenicity through two different types of mouse models. The dot-blot and basophil activation test assays revealed strong immunoreactivity for HTM, ATM, and MTM, with HTM exhibiting significantly lower levels compared to ATM. In the BALB/c mouse sensitization model, all TM groups stimulated the production of specific antibodies, elicited IgE-mediated immediate hypersensitivity responses, and caused an imbalance in the IL-4/IFN-γ ratio. Similarly, in the BALB/c mouse model of food allergy, all TM variants induced IgE-mediated type I hypersensitivity responses, leading to the development of food allergies characterized by clinical symptoms and an imbalance in the IL-4/IFN-γ ratio. The stimulation ability of sensitization and the severity of food allergies consistently ranked as ATM > MTM > HTM. Through an in-depth analysis of non-polar amino acid frequency and polar hydrogen bonds, HTM exhibited higher frequencies of non-polar amino acids in its amino acid sequence and IgE epitopes, in comparison with ATM and MTM. Furthermore, HTM demonstrated a lower number of polar hydrogen bonds in IgE epitopes. Overall, HTM exhibited the lowest allergenic potential in both allergic patients and mouse models, likely due to its lower polarity in the amino acid sequence and IgE epitopes.
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Affiliation(s)
- Xinyu 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, Fujian 361021, China.
| | - Xinrong He
- 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, Fujian 361021, China.
| | - Xinya Wang
- Department of Bioinformatics, Fujian Key Laboratory of Medical Bioinformatics, Institute of Precision Medicine, School of Medical Technology and Engineering, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Lianzhong Luo
- Engineering Research Center of Marine Biopharmaceutical Resources, Fujian Province University, Xiamen Medical College, Xiamen, Fujian 361023, China
| | - Yubao Li
- Medical Center of Jimei University, Xiamen, Fujian 361021, China
| | - Dong Lai
- Xiamen Medical College Affiliated Second Hospital, Xiamen, Fujian 361021, China
| | - Hong 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, Fujian 361021, China.
| | - Jingwen 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, Fujian 361021, China.
| | - Shitao Rao
- Department of Bioinformatics, Fujian Key Laboratory of Medical Bioinformatics, Institute of Precision Medicine, School of Medical Technology and Engineering, Fujian Medical University, Fuzhou, Fujian 350122, China
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
| | - Guangming 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, Fujian 361021, China.
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Smits NG, De Dominicis E, Koops AJ, Kraan R, Saner S, Van Der Fels-Klerx H, Hoek-van den Hil E. Comparison of commercial allergen ELISA kits for egg detection in food matrices. Heliyon 2023; 9:e19687. [PMID: 37780752 PMCID: PMC10539936 DOI: 10.1016/j.heliyon.2023.e19687] [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] [Received: 07/17/2023] [Revised: 08/28/2023] [Accepted: 08/30/2023] [Indexed: 10/03/2023] Open
Abstract
Consumption of low levels of egg already can evoke harmful physiological responses in humans in those allergic to eggs. By detection of egg in food products, using Egg ELISA kits to determine its unintended presence, food producers can respond to avoid potential safety or quality risks of their products. Selection of an ELISA kit fit for the issue at hand is challenging due to, amongst others, lack of information on assay performances with specified matrices. In this study, performances of seven commercial egg ELISA kits are compared for nine different relevant matrices: cookie, chocolate, pasta, dressing, stock cube, wine, vegetable drink and milk, ice cream and meat/meat replacers. The presence of egg was unified for all ELISA kits to mg total egg protein kg-1 food product. In every matrix, kit performances for recovery, intra- and interassay were compared, and also processing is accounted for by determination of egg in incurred samples. All seven kits were able to detect egg qualitatively at the VITAL3 ED01 level of 0.2 mg total egg protein and the corresponding relevant portion size for each matrix. For quantitative results, each ELISA kit showed an increase in detected egg concentration with increased egg levels and performed within the set criteria for recovery for the cookie, chocolate, stock cube and wine. For pasta, vegetable drink and milk, ice cream, and salad dressing, recovery of egg was within the set criteria for at least 4 ELISA kits. Most challenging matrices were meat/meat replacers, showing high matrix effects which could not be explained by the possible egg presence in the cognate blank. Only one ELISA kit was able to recover egg within the set criteria for the meat/meat replacer matrix. Results enable food industry to choose for ELISA kits suitable for egg detection in the matrix of interest.
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Affiliation(s)
- Nathalie G.E. Smits
- Wageningen Food Safety Research, Wageningen University and Research, P.O. Box 230, 6700, AE, Wageningen, the Netherlands
| | | | - Andries J. Koops
- Wageningen Food Safety Research, Wageningen University and Research, P.O. Box 230, 6700, AE, Wageningen, the Netherlands
| | - Rian Kraan
- Wageningen Food Safety Research, Wageningen University and Research, P.O. Box 230, 6700, AE, Wageningen, the Netherlands
| | - Samim Saner
- Mérieux NutriSciences R&D, Quality, Operation, France
| | - H.J. Van Der Fels-Klerx
- Wageningen Food Safety Research, Wageningen University and Research, P.O. Box 230, 6700, AE, Wageningen, the Netherlands
| | - Elise Hoek-van den Hil
- Wageningen Food Safety Research, Wageningen University and Research, P.O. Box 230, 6700, AE, Wageningen, the Netherlands
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Ji NR, Han XY, Yu CC, He XR, Rao ST, Huan F, Liu H, Chen GX, Cao MJ, Liu GM. Identification of linear epitopes and their major role in the immunoglobulin E-binding capacity of tropomyosin from Alectryonella plicatula. Food Funct 2022; 13:9078-9090. [PMID: 35943407 DOI: 10.1039/d2fo01713j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tropomyosin (TM) is an important allergen in molluscans. However, there was a lack of information about TM as an allergen in oysters. TM was purified and identified from Alectryonella plicatula (ATM), and its primary sequence was cloned and encoded with 284 amino acids (AAs). Chemical denaturants were used to destroy the structure to confirm that linear epitopes played a major role in the immunoglobulin E-binding capacity of ATM. Subsequently, nine linear epitopes were identified using a serological test. The peptide with AA27-41 was regarded as the key epitope because it could be recognized strongly by most sera of oyster-sensitive individuals in comparison to other epitope peptides. Finally, the epitopes and the primary sequence of TM among shellfish were aligned to find the two conserved epitopes (AA117-132 and AA164-178) in oyster, octopus, abalone, scallop, clam, shrimp, and crab. Overall, these data provide a foundation for the allergenicity and cross-reactivity of TM.
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Affiliation(s)
- Nai-Ru Ji
- 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, Fujian 361021, China.
| | - Xin-Yu 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, Fujian 361021, China.
| | - Chen-Chen Yu
- 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, Fujian 361021, China.
| | - Xin-Rong He
- 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, Fujian 361021, China.
| | - Shi-Tao Rao
- School of Medical Technology and Engineering, Fujian Medical University, Fuzhou, Fujian 350004, 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, Fujian 361021, China.
| | - Hong 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, Fujian 361021, China.
| | - Gui-Xia Chen
- Women and Children's Hospital Affiliated to Xiamen University, Xiamen, Fujian 361003, China
| | - Min-Jie Cao
- 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, Fujian 361021, 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, Fujian 361021, China.
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