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Comstock SS, Maleki SJ, Teuber SS. Boiling and Frying Peanuts Decreases Soluble Peanut (Arachis Hypogaea) Allergens Ara h 1 and Ara h 2 But Does Not Generate Hypoallergenic Peanuts. PLoS One 2016; 11:e0157849. [PMID: 27310538 PMCID: PMC4911009 DOI: 10.1371/journal.pone.0157849] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 06/06/2016] [Indexed: 11/18/2022] Open
Abstract
Peanut allergy continues to be a problem in most developed countries of the world. We sought a processing method that would alter allergenic peanut proteins, such that allergen recognition by IgE from allergic individuals would be significantly reduced or eliminated. Such a method would render accidental exposures to trace amounts of peanuts safer. A combination of boiling and frying decreased recovery of Ara h 1 and Ara h 2 at their expected MWs. In contrast, treatment with high pressures under varying temperatures had no effect on protein extraction profiles. Antibodies specific for Ara h 1, Ara h 2, and Ara h 6 bound proteins extracted from raw samples but not in boiled/fried samples. However, pre-incubation of serum with boiled/fried extract removed most raw peanut-reactive IgE from solution, including IgE directed to Ara h 1 and 2. Thus, this method of processing is unlikely to generate a peanut product tolerated by peanut allergic patients. Importantly, variability in individual patients' IgE repertoires may mean that some patients' IgE would bind fewer polypeptides in the sequentially processed seed.
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Affiliation(s)
- Sarah S Comstock
- Department of Internal Medicine, Division of Rheumatology, Allergy and Clinical Immunology, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Soheila J Maleki
- United States Department of Agriculture-Agricultural Research Service-Southern Regional Research Center (USDA-ARS-SRRC), New Orleans, Louisiana, United States of America
| | - Suzanne S Teuber
- Department of Internal Medicine, Division of Rheumatology, Allergy and Clinical Immunology, School of Medicine, University of California Davis, Davis, California, United States of America
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52
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Allergenicity attributes of different peanut market types. Food Chem Toxicol 2016; 91:82-90. [DOI: 10.1016/j.fct.2016.02.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 01/28/2016] [Accepted: 02/19/2016] [Indexed: 11/20/2022]
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53
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Plundrich NJ, White BL, Dean LL, Davis JP, Foegeding EA, Lila MA. Stability and immunogenicity of hypoallergenic peanut protein-polyphenol complexes during in vitro pepsin digestion. Food Funct 2016; 6:2145-54. [PMID: 26007692 DOI: 10.1039/c5fo00162e] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Allergenic peanut proteins are relatively resistant to digestion, and if digested, metabolized peptides tend to remain large and immunoreactive, triggering allergic reactions in sensitive individuals. In this study, the stability of hypoallergenic peanut protein-polyphenol complexes was evaluated during simulated in vitro gastric digestion. When digested with pepsin, the basic subunit of the peanut allergen Ara h 3 was more rapidly hydrolyzed in peanut protein-cranberry or green tea polyphenol complexes compared to uncomplexed peanut flour. Ara h 2 was also hydrolyzed more quickly in the peanut protein-cranberry polyphenol complex than in uncomplexed peanut flour. Peptides from peanut protein-cranberry polyphenol complexes and peanut protein-green tea polyphenol complexes were substantially less immunoreactive (based on their capacity to bind to peanut-specific IgE from patient plasma) compared to peptides from uncomplexed peanut flour. These results suggest that peanut protein-polyphenol complexes may be less immunoreactive passing through the digestive tract in vivo, contributing to their attenuated allergenicity.
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Affiliation(s)
- Nathalie J Plundrich
- Plants for Human Health Institute, Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, North Carolina Research Campus, 600 Laureate Way, Kannapolis, NC 28081, USA.
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54
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van Erp FC, Klemans RJB, Meijer Y, van der Ent CK, Knulst AC. Using Component-Resolved Diagnostics in the Management of Peanut-Allergic Patients. CURRENT TREATMENT OPTIONS IN ALLERGY 2016; 3:169-180. [PMID: 27330930 PMCID: PMC4891380 DOI: 10.1007/s40521-016-0080-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Instead of relying on crude peanut extract, component-resolved diagnostics (CRD) uses sensitization to allergenic proteins within peanut. In this review, we describe the recent advances and future perspectives of the use of CRD in the management of peanut-allergic patients. There is strong evidence that sensitization to Ara h 2 is the best predictor for clinically relevant peanut allergy in children and adults. Isolated sensitization to other peanut components is only rarely present in patients with systemic reactions to peanut. It is, however, important to remark that cut-off points of sIgE to Ara h 2 that predict tolerance or allergy vary between different study populations, different age groups and geographical regions, and validation studies performed in different settings are necessary to implement cut-offs in daily practice. Future studies should focus on the role of CRD in risk-assessment early in life, predicting long-term tolerance and monitoring treatment responses following immunotherapy.
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Affiliation(s)
- F C van Erp
- Department of Paediatric Pulmonology and Allergology, University Medical Centre Utrecht, Utrecht, The Netherlands ; Department of Paediatric Pulmonology and Allergology, University Medical Center Utrecht, Wilhelmina Children's Hospital, P O Box 85090, 3508 AB Utrecht, The Netherlands
| | - R J B Klemans
- Department of Dermatology and Allergology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Y Meijer
- Department of Paediatric Pulmonology and Allergology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - C K van der Ent
- Department of Paediatric Pulmonology and Allergology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - A C Knulst
- Department of Dermatology and Allergology, University Medical Centre Utrecht, Utrecht, The Netherlands
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55
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Iqbal A, Shah F, Hamayun M, Ahmad A, Hussain A, Waqas M, Kang SM, Lee IJ. Allergens of Arachis hypogaea and the effect of processing on their detection by ELISA. Food Nutr Res 2016; 60:28945. [PMID: 26931300 PMCID: PMC4773821 DOI: 10.3402/fnr.v60.28945] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 02/02/2016] [Accepted: 02/06/2016] [Indexed: 11/14/2022] Open
Abstract
Food allergies are an emerging public health problem in industrialized areas of the world. They represent a considerable health problem in these areas because of the relatively high number of reported cases. Usually, food allergens are proteins or glycoproteins with a molecular mass ranging from 10 to 70 kDa. Among the food allergies, peanut is accounted to be responsible for more than 50% of the food allergy fatalities. Threshold doses for peanut allergenic reactions have been found to range from as low as 100 µg to 1 g of peanut protein, which equal to 400 µg to 4 g peanut meal. Allergens from peanut are mainly seed storage proteins that are composed of conglutin, vicilin, and glycinin families. Several peanut proteins have been identified to induce allergic reactions, particularly Ara h 1-11. This review is mainly focused on different classes of peanut allergens, the effect of thermal and chemical treatment of peanut allergens on the IgY binding and detectability of these allergens by enzyme linked immunosorbent assay (ELISA) to provide knowledge for food industry.
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Affiliation(s)
- Amjad Iqbal
- Department of Food Safety and Food Quality, University of Gent, Gent, Belgium
- Department of Agriculture, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Farooq Shah
- Department of Agriculture, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Muhammad Hamayun
- Department of Botany, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Ayaz Ahmad
- Department of Biotechnology, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Anwar Hussain
- Department of Botany, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Muhammad Waqas
- School of Applied Biosciences, College of Agriculture and Life Science, Kyungpook National University, Daegu, South Korea
| | - Sang-Mo Kang
- School of Applied Biosciences, College of Agriculture and Life Science, Kyungpook National University, Daegu, South Korea
| | - In-Jung Lee
- School of Applied Biosciences, College of Agriculture and Life Science, Kyungpook National University, Daegu, South Korea;
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56
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Parker CH, Khuda SE, Pereira M, Ross MM, Fu TJ, Fan X, Wu Y, Williams KM, DeVries J, Pulvermacher B, Bedford B, Zhang X, Jackson LS. Multi-allergen Quantitation and the Impact of Thermal Treatment in Industry-Processed Baked Goods by ELISA and Liquid Chromatography-Tandem Mass Spectrometry. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:10669-10680. [PMID: 26595064 DOI: 10.1021/acs.jafc.5b04287] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Undeclared food allergens account for 30-40% of food recalls in the United States. Compliance with ingredient labeling regulations and the implementation of effective manufacturing allergen control plans require the use of reliable methods for allergen detection and quantitation in complex food products. The objectives of this work were to (1) produce industry-processed model foods incurred with egg, milk, and peanut allergens, (2) compare analytical method performance for allergen quantitation in thermally processed bakery products, and (3) determine the effects of thermal treatment on allergen detection. Control and allergen-incurred cereal bars and muffins were formulated in a pilot-scale industry processing facility. Quantitation of egg, milk, and peanut in incurred baked goods was compared at various processing stages using commercial enzyme-linked immunosorbent assay (ELISA) kits and a novel multi-allergen liquid chromatography (LC)-tandem mass spectrometry (MS/MS) multiple-reaction monitoring (MRM) method. Thermal processing was determined to negatively affect the recovery and quantitation of egg, milk, and peanut to different extents depending on the allergen, matrix, and analytical test method. The Morinaga ELISA and LC-MS/MS quantitative methods reported the highest recovery across all monitored allergens, whereas the ELISA Systems, Neogen BioKits, Neogen Veratox, and R-Biopharm ELISA Kits underperformed in the determination of allergen content of industry-processed bakery products.
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Affiliation(s)
- Christine H Parker
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration , 5100 Paint Branch Parkway, College Park, Maryland 20740, United States
| | - Sefat E Khuda
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration , 8301 Muirkirk Road, Laurel, Maryland 20708, United States
| | - Marion Pereira
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration , 8301 Muirkirk Road, Laurel, Maryland 20708, United States
| | - Mark M Ross
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration , 5100 Paint Branch Parkway, College Park, Maryland 20740, United States
| | - Tong-Jen Fu
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration , 6502 South Archer Road, Bedford Park, Illinois 60501, United States
| | - Xuebin Fan
- Institute for Food Safety and Health, Illinois Institute of Technology , Bedford Park, Illinois 60501, United States
| | - Yan Wu
- Institute for Food Safety and Health, Illinois Institute of Technology , Bedford Park, Illinois 60501, United States
| | - Kristina M Williams
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration , 8301 Muirkirk Road, Laurel, Maryland 20708, United States
| | - Jonathan DeVries
- James Ford Bell Technical Center, General Mills , 9000 Plymouth Avenue North, Golden Valley, Minnesota 55427, United States
| | - Brian Pulvermacher
- James Ford Bell Technical Center, General Mills , 9000 Plymouth Avenue North, Golden Valley, Minnesota 55427, United States
| | - Binaifer Bedford
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration , 6502 South Archer Road, Bedford Park, Illinois 60501, United States
| | - Xi Zhang
- Institute for Food Safety and Health, Illinois Institute of Technology , Bedford Park, Illinois 60501, United States
| | - Lauren S Jackson
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration , 6502 South Archer Road, Bedford Park, Illinois 60501, United States
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57
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Chokshi NY, Sicherer SH. Interpreting IgE sensitization tests in food allergy. Expert Rev Clin Immunol 2015; 12:389-403. [DOI: 10.1586/1744666x.2016.1124761] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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58
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Effect of thermal and electric field treatment on the conformation of Ara h 6 peanut protein allergen. INNOV FOOD SCI EMERG 2015. [DOI: 10.1016/j.ifset.2015.03.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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59
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van Hoffen E, van der Kleij HPM, den Hartog Jager CF, van Doorn WA, Knol EF, Opstelten DJ, Koppelman SJ, Knulst AC. Chemical modification of peanut conglutin reduces IgE reactivity but not T cell reactivity in peanut-allergic patients. Clin Exp Allergy 2015; 44:1558-66. [PMID: 24717146 DOI: 10.1111/cea.12319] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 02/15/2014] [Accepted: 03/24/2014] [Indexed: 11/29/2022]
Abstract
BACKGROUND Specific immunotherapy for peanut allergy is associated with significant side-effects. Chemically modified allergens may provide a safer alternative. OBJECTIVE This study aimed to analyse the immunogenicity and allergenicity of modified peanut conglutin. METHODS Native peanut conglutin and two modifications thereof were generated (RA and RAGA). Conglutin-specific T cell lines from 11 peanut-allergic patients were analysed for proliferation and cytokine production. Sera from 14 patients were analysed for IgE/IgG1/IgG4 binding by immunoblot and ELISA. IgE reactivity was analysed by direct and indirect basophil activation test (BAT), in presence and absence of patient plasma or CD32-blocking antibodies. RESULTS T cell proliferation to RA was unchanged, and proliferation to RAGA was reduced compared to native conglutin. Cytokine profiles remained unchanged. IgE, IgG1 and IgG4 binding to RA and RAGA was significantly reduced. In the direct BAT, the relative potency of modified conglutin was decreased in 67% and increased/similar in 33% of the patients. In the indirect BAT, RA and RAGA were 10-100 times less potent than native conglutin. Addition of plasma to the indirect BAT increased the relative potency of modified conglutin in patients with high peanut-specific IgG levels. This was mediated via blocking of the response to native conglutin, most likely by soluble IgG, and not via CD32. CONCLUSION AND CLINICAL RELEVANCE Chemical modification of peanut conglutin by RA retains immunogenicity and reduces allergenicity and may be a promising approach for development of a curative treatment for peanut allergy. In a subgroup of patients, where the reactivity of native conglutin is already partially blocked by IgG, the effect of the modification of conglutin is less pronounced.
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Affiliation(s)
- E van Hoffen
- Department of Dermatology/Allergology, University Medical Center Utrecht, Utrecht, The Netherlands
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60
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Bencharitiwong R, van der Kleij HP, Koppelman SJ, Nowak-Węgrzyn A. Effect of chemical modifications on allergenic potency of peanut proteins. Allergy Asthma Proc 2015; 36:185-91. [PMID: 25976435 DOI: 10.2500/aap.2015.36.3840] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Modification of native peanut extracts could reduce adverse effects of peanut immunotherapy. OBJECTIVE We sought to compare native and chemically modified crude peanut extract (CPE) and major peanut allergens Ara h 2 and Ara h 6 in a mediator-release assay based on the rat basophilic leukemia (RBL) cell line transfected with human Fcε receptor. METHODS Native Ara h 2/6 was reduced and alkylated (RA), with or without additional glutaraldehyde treatment (RAGA). CPE was reduced and alkylated. Sera of subjects with peanut allergy (16 males; median age 7 years) were used for overnight RBL-passive sensitization. Cells were stimulated with 0.1 pg/mL to 10 μg/mL of peanut. β-N-acetylhexosaminidase release (NHR) was used as a marker of RBL degranulation, expressed as a percentage of total degranulation caused by Triton X. RESULTS Median peanut-specific immunoglobulin E was 233 kUA/L. Nineteen subjects were responders, NHR ≥ 10% in the mediator release assay. Responders had reduced NHR by RA and RAGA compared with the native Ara h 2/6. Modification resulted in a later onset of activation by 10- to 100-fold in concentration and a lowering of the maximum release. Modified RA-Ara h 2/6 and RAGA-Ara h 2/6 caused significantly lower maximum mediator release than native Ara h 2/6, at protein concentrations 0.1, 1, and 10 ng/mL (p < 0.001, < 0.001, and < 0.001, respectively, for RA; and < 0.001, 0.026, and 0.041, respectively, for RAGA). RA-CPE caused significantly lower maximum NHR than native CPE, at protein concentration 1 ng/mL (p < 0.001) and 10 ng/mL (p < 0.002). Responders had high rAra h 2 immunoglobulin E (mean, 61.1 kUA/L; p < 0.001) and higher NHR in mediator release assay to native Ara h 2/6 than CPE, which indicates that Ara h 2/6 were the most relevant peanut allergens in these responders. CONCLUSIONS Chemical modification of purified native Ara h 2 and Ara h 6 reduced mediator release in an in vitro assay ∼100-fold, which indicates decreased allergenicity for further development of the alternative candidate for safe peanut immunotherapy.
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Affiliation(s)
- Ramon Bencharitiwong
- Division of Pediatric Allergy and Immunology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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61
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Jayasena S, Smits M, Fiechter D, de Jong A, Nordlee J, Baumert J, Taylor SL, Pieters RH, Koppelman SJ. Comparison of six commercial ELISA kits for their specificity and sensitivity in detecting different major peanut allergens. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:1849-1855. [PMID: 25651402 DOI: 10.1021/jf504741t] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Six commercial peanut enzyme-linked immunosorbent assay kits were assessed for their ability to recover peanut from the standard reference material 2387 peanut butter and also for their specificity in detecting four major peanut allergens, Ara h 1, Ara h 2, Ara h 3, and Ara h 6. The percentage recovery of peanut from peanut butter differed across different kits as well as at different sample concentrations. The highest recovery was observed with the Romer and R-Biopharm kits, while four other kits were found to underestimate the protein content of the reference peanut butter samples. Five of the kits were most sensitive in detecting Ara h 3 followed by Ara h 1, while hardly recognizing Ara h 2 and Ara h 6. The other kit showed the highest sensitivity to Ara h 2 and Ara h 6, while Ara h 1 and Ara h 3 were poorly recognized. Although Ara h 2 and Ara h 6 are known to be heat stable and more potent allergens, antisera specific to any of these four peanut proteins/allergens may serve as good markers for the detection of peanut residues.
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Affiliation(s)
- Shyamali Jayasena
- Food Allergy Research and Resource Program, Department of Food Science & Technology, University of Nebraska , 143 Food Industry Complex, Lincoln, Nebraska 68583-0919, United States
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62
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Bernard H, Guillon B, Drumare MF, Paty E, Dreskin SC, Wal JM, Adel-Patient K, Hazebrouck S. Allergenicity of peanut component Ara h 2: Contribution of conformational versus linear hydroxyproline-containing epitopes. J Allergy Clin Immunol 2014; 135:1267-74.e1-8. [PMID: 25483599 DOI: 10.1016/j.jaci.2014.10.025] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 10/03/2014] [Accepted: 10/06/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND The 2S-albumin Ara h 2 is the most potent peanut allergen and a good predictor of clinical reactivity in allergic children. Posttranslational hydroxylation of proline residues occurs in DPYSP(OH)S motifs, which are repeated 2 or 3 times in different isoforms. OBJECTIVES We investigated the effect of proline hydroxylation on IgE binding and the relative contributions of linear and conformational epitopes to Ara h 2 allergenicity. METHODS Peptides containing DPYSP(OH)S motifs were synthesized. A recombinant variant of Ara h 2 without DPYSP(OH)S motifs was generated by means of deletion mutagenesis. IgE reactivity of 18 French and 5 American patients with peanut allergy toward synthetic peptides and recombinant allergens was assessed by using IgE-binding inhibition assays and degranulation tests of humanized rat basophilic leukemia cells. RESULTS Hydroxyproline-containing peptides exhibited an IgE-binding activity equivalent to that of the unfolded Ara h 2. In contrast, corresponding peptides without hydroxyprolines displayed a very weak IgE-binding capacity. Despite removal of the DPYSP(OH)S motifs, the deletion variant still displayed Ara h 2 conformational epitopes. The IgE-binding capacity of Ara h 2 was then recapitulated with an equimolar mixture of a hydroxylated peptide and the deletion variant. Hydroxylated peptides of 15 and 27 amino acid residues were also able to trigger cell degranulation. CONCLUSIONS Sensitization toward linear and conformational epitopes of Ara h 2 is variable among patients with peanut allergy. Optimal IgE binding to linear epitopes of Ara h 2 requires posttranslational hydroxylation of proline residues. The absence of hydroxyprolines could then affect the accuracy of component-resolved diagnostics by using rAra h 2.
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Affiliation(s)
- Hervé Bernard
- INRA, UR 496, Unité d'Immuno-Allergie Alimentaire, Jouy-en-Josas, France; CEA, iBiTecS/Service de Pharmacologie et d'Immunoanalyse, Gif-sur-Yvette, France
| | - Blanche Guillon
- INRA, UR 496, Unité d'Immuno-Allergie Alimentaire, Jouy-en-Josas, France; CEA, iBiTecS/Service de Pharmacologie et d'Immunoanalyse, Gif-sur-Yvette, France
| | - Marie-Françoise Drumare
- INRA, UR 496, Unité d'Immuno-Allergie Alimentaire, Jouy-en-Josas, France; CEA, iBiTecS/Service de Pharmacologie et d'Immunoanalyse, Gif-sur-Yvette, France
| | - Evelyne Paty
- Université Paris Descartes-Assistance Publique des Hôpitaux de Paris, Hôpital Necker Enfants Malades, Paris, France
| | - Stephen C Dreskin
- Division of Allergy and Clinical Immunology, Department of Medicine, University of Colorado Denver, Aurora, Colo
| | - Jean-Michel Wal
- INRA, UR 496, Unité d'Immuno-Allergie Alimentaire, Jouy-en-Josas, France; CEA, iBiTecS/Service de Pharmacologie et d'Immunoanalyse, Gif-sur-Yvette, France
| | - Karine Adel-Patient
- INRA, UR 496, Unité d'Immuno-Allergie Alimentaire, Jouy-en-Josas, France; CEA, iBiTecS/Service de Pharmacologie et d'Immunoanalyse, Gif-sur-Yvette, France
| | - Stéphane Hazebrouck
- INRA, UR 496, Unité d'Immuno-Allergie Alimentaire, Jouy-en-Josas, France; CEA, iBiTecS/Service de Pharmacologie et d'Immunoanalyse, Gif-sur-Yvette, France.
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63
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Aalberse RC, Knol EF. Historic overview of allergy research in the Netherlands. Immunol Lett 2014; 162:163-72. [PMID: 25455604 DOI: 10.1016/j.imlet.2014.10.015] [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] [Indexed: 11/18/2022]
Abstract
Research in allergy has a long history in the Netherlands, although the relation with immunology has not always been appreciated. In many aspects Dutch researchers have made major contribution in allergy research. This ranges from the first characterization of house dust mite as an important allergen, the first characterization of human Th2 and Th1 T cell clones, to the development of diagnostic test systems. In this overview Aalberse and Knol have made an overview of the major contributions of Dutch immunologists in allergy.
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Affiliation(s)
- Rob C Aalberse
- Department of Immunopathology, Sanquin Blood Supply Foundation and Academic Medical Centre, Amsterdam, The Netherlands
| | - Edward F Knol
- Department of Immunology, University Medical Center Utrecht, The Netherlands; Department of Dermatology and Allergology, University Medical Center Utrecht, The Netherlands.
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64
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Abstract
Accurately diagnosing a patient with a possible food allergy is important to avoid unnecessary dietary restrictions and prevent life-threatening reactions. Routine testing modalities have limited accuracy, and an oral food challenge is often required to make a definitive diagnosis. Given that they are labor intensive and risk inducing an allergic reaction, several alternative diagnostic modalities have been investigated. Testing for IgE antibodies to particular protein components in foods has shown promise to improve diagnostics and has entered clinical practice. Additional modalities show potential, including epitope binding, T-cell studies, and basophil activation.
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Affiliation(s)
- Jacob D Kattan
- Department of Pediatric Allergy and Immunology, Jaffe Food Allergy Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1198, New York, NY 10029, USA.
| | - Scott H Sicherer
- Department of Pediatric Allergy and Immunology, Jaffe Food Allergy Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, Box 1198, New York, NY 10029, USA
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65
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Klemans RJB, Knol EF, Bruijnzeel-Koomen CAFM, Knulst AC. The diagnostic accuracy of specific IgE to Ara h 6 in adults is as good as Ara h 2. Allergy 2014; 69:1112-4. [PMID: 24813113 DOI: 10.1111/all.12424] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2014] [Indexed: 11/29/2022]
Abstract
Specific IgE (sIgE) to Ara h 2 is useful in diagnosing peanut allergy. Our aim was to assess the diagnostic value of sIgE to Ara h 6, another 2S albumin, in an adult population suspected of peanut allergy. Subjects with suspected peanut allergy between 2002 and 2013 were included if a diagnostic double-blind, placebo-controlled food challenge with peanut was performed. sIgE to Ara h 2 and Ara h 6 was measured by ImmunoCAP ISAC 112. Of 107 challenged subjects, 65 had a positive challenge (61%). The discriminative ability of sIgE to Ara h 2 and Ara h 6 was comparable: AUC 0.81 vs. 0.82. Positive predictive value for both tests was 95% using a cutoff value ≥1 ISU/l with poor corresponding sensitivity values (58% for Ara h 2, 62% for Ara h 6), but good specificity values (95% for both tests). In conclusion, the diagnostic value of sIgE to Ara h 6 on population level was as good as sIgE to Ara h 2. On individual level, however, 5% of the subjects showed contradicting results between both tests using a cutoff of 0.3 ISU/l, leading to a risk of misdiagnosis if only one of both tests is used.
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Affiliation(s)
- R. J. B. Klemans
- Department of Dermatology and Allergology; University Medical Center Utrecht; Utrecht the Netherlands
| | - E. F. Knol
- Department of Dermatology and Allergology; University Medical Center Utrecht; Utrecht the Netherlands
- Department of Immunology; University Medical Center Utrecht; Utrecht the Netherlands
| | | | - A. C. Knulst
- Department of Dermatology and Allergology; University Medical Center Utrecht; Utrecht the Netherlands
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66
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Plundrich NJ, Kulis M, White BL, Grace MH, Guo R, Burks AW, Davis JP, Lila MA. Novel strategy to create hypoallergenic peanut protein-polyphenol edible matrices for oral immunotherapy. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:7010-21. [PMID: 24758688 DOI: 10.1021/jf405773b] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Peanut allergy is an IgE-mediated hypersensitivity. Upon peanut consumption by an allergic individual, epitopes on peanut proteins bind and cross-link peanut-specific IgE on mast cell and basophil surfaces triggering the cells to release inflammatory mediators responsible for allergic reactions. Polyphenolic phytochemicals have high affinity to bind proteins and form soluble and insoluble complexes with unique functionality. This study investigated the allergenicity of polyphenol-fortified peanut matrices prepared by complexing various polyphenol-rich plant juices and extracts with peanut flour. Polyphenol-fortified peanut matrices reduced IgE binding to one or more peanut allergens (Ara h 1, Ara h 2, Ara h 3, and Ara h 6). Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) suggested changes in secondary protein structure. Peanut protein-cranberry polyphenol fortified matrices triggered significantly less basophil degranulation than unmodified flour in an ex vivo assay using human blood and less mast cell degranulation when used to orally challenge peanut-allergic mice. Polyphenol fortification of peanut flour resulted in a hypoallergenic matrix with reduced IgE binding and degranulation capacity, likely due to changes in protein secondary structure or masking of epitopes, suggesting potential applications for oral immunotherapy.
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Affiliation(s)
- Nathalie J Plundrich
- Plants for Human Health Institute, Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University , North Carolina Research Campus, Kannapolis, North Carolina 28081, United States
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67
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Lupinek C, Wollmann E, Baar A, Banerjee S, Breiteneder H, Broecker BM, Bublin M, Curin M, Flicker S, Garmatiuk T, Hochwallner H, Mittermann I, Pahr S, Resch Y, Roux KH, Srinivasan B, Stentzel S, Vrtala S, Willison LN, Wickman M, Lødrup-Carlsen KC, Antó JM, Bousquet J, Bachert C, Ebner D, Schlederer T, Harwanegg C, Valenta R. Advances in allergen-microarray technology for diagnosis and monitoring of allergy: the MeDALL allergen-chip. Methods 2014; 66:106-19. [PMID: 24161540 PMCID: PMC4687054 DOI: 10.1016/j.ymeth.2013.10.008] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 10/07/2013] [Accepted: 10/09/2013] [Indexed: 01/23/2023] Open
Abstract
Allergy diagnosis based on purified allergen molecules provides detailed information regarding the individual sensitization profile of allergic patients, allows monitoring of the development of allergic disease and of the effect of therapies on the immune response to individual allergen molecules. Allergen microarrays contain a large variety of allergen molecules and thus allow the simultaneous detection of allergic patients' antibody reactivity profiles towards each of the allergen molecules with only minute amounts of serum. In this article we summarize recent progress in the field of allergen microarray technology and introduce the MeDALL allergen-chip which has been developed for the specific and sensitive monitoring of IgE and IgG reactivity profiles towards more than 170 allergen molecules in sera collected in European birth cohorts. MeDALL is a European research program in which allergen microarray technology is used for the monitoring of the development of allergic disease in childhood, to draw a geographic map of the recognition of clinically relevant allergens in different populations and to establish reactivity profiles which are associated with and predict certain disease manifestations. We describe technical advances of the MeDALL allergen-chip regarding specificity, sensitivity and its ability to deliver test results which are close to in vivo reactivity. In addition, the usefulness and numerous advantages of allergen microarrays for allergy research, refined allergy diagnosis, monitoring of disease, of the effects of therapies, for improving the prescription of specific immunotherapy and for prevention are discussed.
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Affiliation(s)
- Christian Lupinek
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Eva Wollmann
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Alexandra Baar
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Srinita Banerjee
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Heimo Breiteneder
- Division of Medical Biotechnology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | | | - Merima Bublin
- Division of Medical Biotechnology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Mirela Curin
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Sabine Flicker
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Tetiana Garmatiuk
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Heidrun Hochwallner
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Irene Mittermann
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Sandra Pahr
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Yvonne Resch
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Kenneth H Roux
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Bharani Srinivasan
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | | | - Susanne Vrtala
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria
| | - Leanna N Willison
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Magnus Wickman
- Sachs' Children's Hospital, Södersjukhuset, Stockholm, Sweden; Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | - Josep Maria Antó
- Centre for Research in Environmental Epidemiology (CREAL), IMIM (Hospital del Mar Research Institute), Universitat Pompeu Fabra, Departament de Ciències Experimentals i de la Salut, CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain
| | - Jean Bousquet
- University Hospital of Montpellier, Hôpital Arnaud de Villeneuve, Montpellier, INSERM 1018, Villejuif, France
| | - Claus Bachert
- Upper Airways Research Laboratory, University Hospital Ghent, Belgium
| | - Daniel Ebner
- Phadia Multiplexing, Thermo Fisher Scientific, Vienna, Austria
| | | | | | - Rudolf Valenta
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Austria.
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Koid AE, Chapman MD, Hamilton RG, van Ree R, Versteeg SA, Dreskin SC, Koppelman SJ, Wünschmann S. Ara h 6 complements Ara h 2 as an important marker for IgE reactivity to peanut. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:206-13. [PMID: 24328145 PMCID: PMC4055559 DOI: 10.1021/jf4022509] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The similarities of two major peanut allergens, Ara h 2 and Ara h 6, in molecular size, amino acid sequence, and structure have made it difficult to obtain natural Ara h 6 free of Ara h 2. The objectives of this study were to purify natural Ara h 6 that is essentially free of Ara h 2 and to compare its IgE reactivity and potency in histamine release assays to Ara h 2. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the highly purified allergen (<0.01% Ara h 2) revealed a single 14.5 kD band, and the identity of Ara h 6 was confirmed by liquid chromatography-tandem mass spectrometry. Ara h 6 showed a higher seroprevalence in chimeric IgE enzyme-linked immunosorbent assay (n = 54) but a weaker biological activity in basophil histamine release assays than Ara h 2. Purified Ara h 6 will be useful for diagnostic IgE antibody assays as well as molecular and cellular studies to investigate the immunological mechanisms of peanut allergy.
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Affiliation(s)
- Audrey E Koid
- INDOOR Biotechnologies, Inc., 1216 Harris St, Charlottesville, VA 22903
| | - Martin D Chapman
- INDOOR Biotechnologies, Inc., 1216 Harris St, Charlottesville, VA 22903
| | - Robert G Hamilton
- Johns Hopkins University School of Medicine, 600 N Wolfe St #6-113, Baltimore, MD 21287
| | - Ronald van Ree
- Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam-Zuidoost, The Netherlands
| | - Serge A Versteeg
- Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam-Zuidoost, The Netherlands
| | - Stephen C Dreskin
- University of Colorado Denver, School of Medicine, 1250 14th St, Denver, CO 80202
| | | | - Sabina Wünschmann
- INDOOR Biotechnologies, Inc., 1216 Harris St, Charlottesville, VA 22903
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69
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Abstract
Peanut is recognized as a potent food allergen producing one of the most frequent food allergies. This fact has originated the publication of an elevated number of scientific reports dealing with peanut allergens and, especially, the prevalence of peanut allergy. For this reason, the information available on peanut allergens is increasing and the debate about peanut allergy is always renewed. This article reviews the information currently available on peanut allergens and on the techniques used for their chemical characterization. Moreover, a general overview on the current biotechnological approaches used to reduce or eliminate peanut allergens is also provided.
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Affiliation(s)
- Jorge Sáiz
- Department of Chemistry I, Faculty of Biology, Environmental Sciences, and Chemistry, University of Alcalá, 28871 Alcalá de Henares, Madrid, Spain
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70
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Apostolovic D, Luykx D, Warmenhoven H, Verbart D, Stanic-Vucinic D, de Jong GAH, Velickovic TC, Koppelman SJ. Reduction and alkylation of peanut allergen isoforms Ara h 2 and Ara h 6; characterization of intermediate- and end products. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:2832-42. [PMID: 24145103 DOI: 10.1016/j.bbapap.2013.10.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 09/12/2013] [Accepted: 10/04/2013] [Indexed: 10/26/2022]
Abstract
Conglutins, the major peanut allergens, Ara h 2 and Ara h 6, are highly structured proteins stabilized by multiple disulfide bridges and are stable towards heat-denaturation and digestion. We sought a way to reduce their potent allergenicity in view of the development of immunotherapy for peanut allergy. Isoforms of conglutin were purified, reduced with dithiothreitol and subsequently alkylated with iodoacetamide. The effect of this modification was assessed on protein folding and IgE-binding. We found that all disulfide bridges were reduced and alkylated. As a result, the secondary structure lost α-helix and gained some β-structure content, and the tertiary structure stability was reduced. On a functional level, the modification led to a strongly decreased IgE-binding. Using conditions for limited reduction and alkylation, partially reduced and alkylated proteins were found with rearranged disulfide bridges and, in some cases, intermolecular cross-links were found. Peptide mass finger printing was applied to control progress of the modification reaction and to map novel disulfide bonds. There was no preference for the order in which disulfides were reduced, and disulfide rearrangement occurred in a non-specific way. Only minor differences in kinetics of reduction and alkylation were found between the different conglutin isoforms. We conclude that the peanut conglutins Ara h 2 and Ara h 6 can be chemically modified by reduction and alkylation, such that they substantially unfold and that their allergenic potency decreases.
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Affiliation(s)
- Danijela Apostolovic
- HAL Allergy B.V., J.H. Oortweg 15-17, 2333 CH Leiden, The Netherlands; Faculty of Chemistry, University of Belgrade, Studentski trg 16, 11 000 Belgrade, Serbia
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71
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Zhou Y, Wang JS, Yang XJ, Lin DH, Gao YF, Su YJ, Yang S, Zhang YJ, Zheng JJ. Peanut Allergy, Allergen Composition, and Methods of Reducing Allergenicity: A Review. INTERNATIONAL JOURNAL OF FOOD SCIENCE 2013; 2013:909140. [PMID: 26904614 PMCID: PMC4745518 DOI: 10.1155/2013/909140] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Revised: 06/23/2013] [Accepted: 06/24/2013] [Indexed: 12/22/2022]
Abstract
Peanut allergy affects 1-2% of the world's population. It is dangerous, and usually lifelong, and it greatly decreases the life quality of peanut-allergic individuals and their families. In a word, peanut allergy has become a major health concern worldwide. Thirteen peanut allergens are identified, and they are briefly introduced in this paper. Although there is no feasible solution to peanut allergy at present, many methods have shown great promise. This paper reviews methods of reducing peanut allergenicity, including physical methods (heat and pressure, PUV), chemical methods (tannic acid and magnetic beads), and biological methods (conventional breeding, irradiation breeding, genetic engineering, enzymatic treatment, and fermentation).
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Affiliation(s)
- Yang Zhou
- College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China
| | - Jin-shui Wang
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, China
| | - Xiao-jia Yang
- College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China
| | - Dan-hua Lin
- College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China
| | - Yun-fang Gao
- College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China
| | - Yin-jie Su
- College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China
| | - Sen Yang
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, China
| | - Yan-jie Zhang
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, China
| | - Jing-jing Zheng
- College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China
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72
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IgE cross-reactivity between the major peanut allergen Ara h 2 and the nonhomologous allergens Ara h 1 and Ara h 3. J Allergy Clin Immunol 2013; 132:118-24. [DOI: 10.1016/j.jaci.2013.01.022] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 12/14/2012] [Accepted: 01/17/2013] [Indexed: 11/20/2022]
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73
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Toomer OT, Do A, Pereira M, Williams K. Effect of simulated gastric and intestinal digestion on temporal stability and immunoreactivity of peanut, almond, and pine nut protein allergens. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2013; 61:5903-5913. [PMID: 23742710 DOI: 10.1021/jf400953q] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Current models of digestibility utilize pepsin stability to assess the safety of allergenic versus nonallergenic food proteins. Dietary protein digestion in vivo, however, requires acid denaturation and protease cleavage by pepsin, trypsin, and/or chymotrypsin. The ability of this approach to identify food protein stability in the mammalian gut may be limited. We determined the temporal stability and immunoreactivity of almond, pine nut, and peanut allergenic proteins under simulated physiologic gastric and intestinal digestive conditions in vitro. Gel electrophoresis and immunoblot analyses were used to determine protein stability and immunoreactivity, respectively. Peanut, almond, and pine nut proteins were pepsin- and pancreatin-stable and immunoreactive for up to 1 h after initiation of digestion. Moreover, successive acid denaturation and pepsin and pancreatin cleavage were necessary to hydrolyze these allergenic proteins and reduce their IgG- and IgE-binding capacity, which suggests that digestibility models must be improved for more accurate safety assessment of food allergens.
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Affiliation(s)
- Ondulla T Toomer
- United States Food and Drug Administration , Laurel, Maryland 20708, United States
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74
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Allergen component testing for food allergy: ready for prime time? Curr Allergy Asthma Rep 2013; 13:58-63. [PMID: 23011598 DOI: 10.1007/s11882-012-0311-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Food allergies can cause life-threatening reactions and greatly influence quality of life. Accurate diagnosis of food allergies is important to avoid serious allergic reactions and prevent unnecessary dietary restrictions, but can be difficult. Skin prick testing (SPT) and serum food-specific IgE (sIgE) levels are extremely sensitive testing options, but positive test results to tolerated foods are not uncommon. Allergen component-resolved diagnostics (CRD) have the potential to provide a more accurate assessment in diagnosing food allergies. Recently, a number of studies have demonstrated that CRD may improve the specificity of allergy testing to a variety of foods including peanut, milk, and egg. While it may be a helpful adjunct to current diagnostic testing, CRD is not ready to replace existing methods of allergy testing, as it not as sensitive, is not widely available, and evaluations of component testing for a number of major food allergens are lacking.
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75
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Abstract
Food allergy has become a major public health concern in westernized countries, and allergic reactions to peanuts are particularly common and severe. Allergens are defined as antigens that elicit an IgE response, and most allergenic materials (e.g., pollens, danders, and foods) contain multiple allergenic proteins. This has led to the concept that there are "major" allergens and allergens of less importance. "Major allergens" have been defined as allergens that bind a large amount of IgE from the majority of patients and have biologic activity. However, the ability of an allergen to cross-link complexes of IgE and its high-affinity receptor FcεRI (IgE/FcεRI), which we have termed its allergic effector activity, does not correlate well with assays of IgE binding. To identify the proteins that are the most active allergens in peanuts, we and others have employed in vitro model assays of allergen-mediated cross-linking of IgE/FcεRI complexes and have demonstrated that the most potent allergens are not necessarily those that bind the most IgE. The importance of a specific allergen can be determined by measuring the allergic effector activity of that allergen following purification under non-denaturing conditions and by specifically removing the allergen from a complex allergenic extract either by chromatography or by specific immunodepletion. In our studies of peanut allergens, our laboratory has found that two related allergens, Ara h 2 and Ara h 6, together account for the majority of the effector activity in a crude peanut extract. Furthermore, murine studies demonstrated that Ara h 2 and Ara h 6 are not only the major elicitors of anaphylaxis in this system, but also can effectively desensitize peanut-allergic mice. As a result of these observations, we propose that the definition of a major allergen should be based on the potency of that allergen in assays of allergic effector activity and demonstration that removal of that allergen from an extract results in loss of potency. Using these criteria, Ara h 2 and Ara h 6 are the major peanut allergens.
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Affiliation(s)
- Yonghua Zhuang
- Division of Allergy and Clinical Immunology, Department of Medicine, University of Colorado School of Medicine, 12700 E. 19th Ave., Room 10C03, Aurora, CO 80045, USA
| | - Stephen C. Dreskin
- Division of Allergy and Clinical Immunology, Department of Medicine, University of Colorado School of Medicine, 12700 E. 19th Ave., Room 10C03, Aurora, CO 80045, USA
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76
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Luo C, Hu C, Gao J, Li X, Wu Z, Yang A, Chen H. A potential practical approach to reduce Ara h 6 allergenicity by gamma irradiation. Food Chem 2013. [DOI: 10.1016/j.foodchem.2012.09.091] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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77
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Zhuang Y, Durrani S, Hodges BDM, Dreskin SC, Chen X. Expression of recombinant Ara h 6 in Pichia pastoris but not in Escherichia coli preserves allergic effector function and allows assessment of specific mutations. Mol Nutr Food Res 2012; 56:986-95. [PMID: 22707273 DOI: 10.1002/mnfr.201100827] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
SCOPE Ara h 6 has recently been recognized as an important peanut allergen. Recombinant allergens have been used for analysis of IgE binding, but have not been used to analyze the allergic effector activity that is more relevant to allergic reactions. METHODS AND RESULTS Ara h 6 was expressed as a recombinant protein in both Escherichia coli and Pichia pastoris (rAra h 6-E. coli and rAra h 6-Pichia, respectively). Effector activity was assayed by measuring degranulation of RBL SX-38 cells sensitized with IgE from patients with severe peanut allergy. Compared to native Ara h 6 (nAra h 6), rAra h 6-Pichia had intact effector function whereas rAra h 6-E. coli had significantly reduced function. The lower effector activity in rAra h 6-E. coli compared to nAra h 6 and rAra h 6-Pichia did not appear to be due to differences in posttranslational modifications (analyzed by mass spectrometry and staining for carbohydrates) and may be due to subtle alteration(s) of folding seen on CD analysis and on nonreduced gels. Finally, we introduced point mutations in four important IgE-binding linear epitopes of Ara h 6 and found dramatically reduced allergic effector activity. CONCLUSION Our studies demonstrate the utility of fully functional rAra h 6-Pichia as a starting point for analysis of specific mutations that adversely affect allergic effector function.
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Affiliation(s)
- Yonghua Zhuang
- Department of Medicine, Division of Allergy and Clinical Immunology, University of Colorado Denver, Aurora, CO 80045, USA
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78
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Chen X, Wang Q, El-Mezayen R, Zhuang Y, Dreskin SC. Ara h 2 and Ara h 6 have similar allergenic activity and are substantially redundant. Int Arch Allergy Immunol 2012; 160:251-8. [PMID: 23075924 DOI: 10.1159/000341642] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 07/06/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The moderately homologous (approx. 60%) proteins Ara h 2 and Ara h 6 are the most potent peanut allergens. This study was designed to define the relative individual contributions of Ara h 2 and Ara h 6 to the overall allergenic activity of a crude peanut extract (CPE). METHODS Ara h 2 and Ara h 6 were removed from CPE by gel filtration chromatography. Ara h 2.01, Ara h 2.02 and Ara h 6 were further purified (>99%). The potency of each allergen and the ability of these allergens to reconstitute the allergenic activity of CPE depleted of Ara h 2 and Ara h 6 was measured with RBL SX-38 cells sensitized with IgE from sensitized peanut allergic patients. RESULTS The potency of the native proteins were significantly different (p < 0.0001) although not dramatically so, with a rank order of Ara h 2.01 > Ara h 2.02 > Ara h 6. The addition of either purified Ara h 2 or Ara h 6 independently at their original concentration to CPE depleted of both Ara h 2 and Ara h 6 restored 80-100% of the original CPE allergenic activity. Addition of both Ara h 2 and Ara h 6 consistently completely restored the allergenic activity of CPE. CONCLUSIONS These studies indicate that either Ara h 2 or Ara h 6 independently can account for most of the allergenic activity in a CPE and demonstrate important redundancy in the allergenic activity of these related molecules.
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Affiliation(s)
- Xueni Chen
- Division of Allergy and Clinical Immunology, Department of Medicine, University of Colorado Denver, Aurora, CO 80045, USA
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79
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Ebisawa M, Movérare R, Sato S, Maruyama N, Borres MP, Komata T. Measurement of Ara h 1-, 2-, and 3-specific IgE antibodies is useful in diagnosis of peanut allergy in Japanese children. Pediatr Allergy Immunol 2012; 23:573-81. [PMID: 22831547 DOI: 10.1111/j.1399-3038.2012.01332.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Food challenges are time-consuming, expensive, and not always possible to perform. Therefore, new tools to diagnose food allergy are desired. The aim was to evaluate IgE antibodies to peanut allergens in the diagnosis of peanut allergy in Japanese children using ImmunoCAP(®) and IgE immunoblotting. METHODS The study included 2-13-yr-old consecutive patients (n = 57) referred to our specialist clinic for investigation of current peanut allergy using food challenge. All children had a previous doctor's diagnosis of peanut allergy and were on elimination diet. Serum samples were analyzed for IgE reactivity to peanut, recombinant (r) Ara h 1, 2, 3, 5, 8, and 9. IgE immunoblotting (n = 23) was performed using extracts from raw and roasted peanut. RESULTS Twenty-six of the children failed (allergic group), and 31 passed the peanut challenge (tolerant group). The rAra h 2 ImmunoCAP test was superior in its ability to differentiate between children in the allergic and tolerant groups with a sensitivity and specificity of 88% and 84%, respectively (cutoff, 0.35 kU(A)/l). The combination of rAra h 1, 2, and 3 resulted in a higher specificity (94%) when IgE to all of them was the criteria for positivity. ImmunoCAP generally showed a good agreement with immunoblotting using both raw and roasted peanut for IgE reactivity to Ara h 1, 2, and 3. CONCLUSIONS Measurement of IgE antibodies to rAra h 1, 2, and 3 is useful in the diagnosis of peanut allergy and in the investigation of reactions to raw and roasted peanut.
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Affiliation(s)
- Motohiro Ebisawa
- Department of Allergy, Clinical Research Center for Allergology and Rheumatology, Sagamihara National Hospital, Sagamihara, Kanagawa, Japan.
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80
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Peanut component Ara h 8 sensitization and tolerance to peanut. J Allergy Clin Immunol 2012; 130:468-72. [DOI: 10.1016/j.jaci.2012.05.019] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 04/16/2012] [Accepted: 05/17/2012] [Indexed: 11/21/2022]
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81
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Identification of a new IgE-binding epitope of peanut oleosin that cross-reacts with buckwheat. Biosci Biotechnol Biochem 2012; 76:1182-8. [PMID: 22790944 DOI: 10.1271/bbb.120063] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Peanut and buckwheat induce a severe allergic reaction, anaphylaxis, which is considered to be mediated by immunoglobulin E (IgE). We identified in this study a new IgE-binding epitope of the peanut allergen that cross-reacted with buckwheat. The phosphate-buffered saline-soluble fraction of buckwheat inhibited the binding between IgE and the peanut allergen. A cross-reactive peptide was isolated from the α-chymotrypsin hydrolysate of peanut. Based on the amino acid sequence and mass spectrometric analysis data, the peptide was identified as Ser-Asp-Gln-Thr-Arg-Thr-Gly-Tyr (SDQTRTGY); this sequence is identical to amino acids 2-9 in the N-terminal hydrophilic domain of oleosin 3 which is located on the surface of the lipid storage body. Synthetic SDQTRTGY was found to bind with IgE in the sera of all eight peanut-allergic patients tested. Since many foods of plant origin contain oleosin, the possibility of an anaphylactic cross-reaction in allergic patients should always be considered.
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82
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Kulis M, Chen X, Lew J, Wang Q, Patel OP, Zhuang Y, Murray KS, Duncan MW, Porterfield HS, W Burks A, Dreskin SC. The 2S albumin allergens of Arachis hypogaea, Ara h 2 and Ara h 6, are the major elicitors of anaphylaxis and can effectively desensitize peanut-allergic mice. Clin Exp Allergy 2012; 42:326-36. [PMID: 22288514 DOI: 10.1111/j.1365-2222.2011.03934.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Ara h 2 and Ara h 6, co-purified together in a 13-25 kD fraction (Ara h 2/6; 20 kD fraction) on gel filtration chromatography, account for the majority of effector activity in a crude peanut extract (CPE) when assayed with RBL SX-38 cells sensitized with IgE from human peanut allergic sera. OBJECTIVES To determine if Ara h 2/6 are the primary peanut allergens responsible for allergic reactions in vivo and to determine if Ara h 2/6 would be sufficient to prevent allergic reactions to a complete CPE. METHODS An oral sensitization mouse model of peanut allergy was used to assess the activity of Ara h 2/6 (20 kD) and CPE without the 20 kD fraction (CPE w/o 20 kD) for allergic provocation challenge and immunotherapy. The activity of these preparations was also tested in an assay of histamine release from human basophils in whole blood. RESULTS Compared with mice challenged with control CPE, mice challenged with CPE w/o 20 kD experienced reduced symptoms (P < 0.05) and a smaller decrease in body temperature (P < 0.01). Results with the basophil histamine release assay corroborated these findings (P < 0.01). The mouse model was also used to administer Ara h 2/6 (20 kD) in an immunotherapy protocol, in which peanut-allergic mice treated with the 20 kD fraction experienced significantly reduced symptoms, changes in body temperature, and mast cell protease (MMCP-1) release compared with placebo (P < 0.01 for all parameters). Importantly, immunotherapy with the 20 kD fraction was just as effective as treatment with CPE, whereas CPE w/o 20 kD was significantly less effective for higher dose peanut challenges. CONCLUSIONS AND CLINICAL RELEVANCE Ara h 2/6 are the most potent peanut allergens in vivo and can be used to desensitize peanut-allergic mice. These results have potential implications for clinical research in the areas of diagnosis and immunotherapy for peanut allergy.
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Affiliation(s)
- M Kulis
- Department of Pediatric Allergy and Immunology, Duke University Medical Center, Durham, NC, USA
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83
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Hazebrouck S, Guillon B, Drumare MF, Paty E, Wal JM, Bernard H. Trypsin resistance of the major peanut allergen Ara h 6 and allergenicity of the digestion products are abolished after selective disruption of disulfide bonds. Mol Nutr Food Res 2012; 56:548-57. [DOI: 10.1002/mnfr.201100614] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Stéphane Hazebrouck
- INRA, UR 496, Unité d’Immuno-Allergie Alimentaire, CEA/iBiTeC-S/SPI, CEA de Saclay; Gif-sur-Yvette France
| | - Blanche Guillon
- INRA, UR 496, Unité d’Immuno-Allergie Alimentaire, CEA/iBiTeC-S/SPI, CEA de Saclay; Gif-sur-Yvette France
| | - Marie-Françoise Drumare
- INRA, UR 496, Unité d’Immuno-Allergie Alimentaire, CEA/iBiTeC-S/SPI, CEA de Saclay; Gif-sur-Yvette France
| | - Evelyne Paty
- Université Paris Descartes Assistance Publique des Hôpitaux de Paris; Hôpital Necker Enfants Malades; Paris France
| | - Jean-Michel Wal
- INRA, UR 496, Unité d’Immuno-Allergie Alimentaire, CEA/iBiTeC-S/SPI, CEA de Saclay; Gif-sur-Yvette France
| | - Hervé Bernard
- INRA, UR 496, Unité d’Immuno-Allergie Alimentaire, CEA/iBiTeC-S/SPI, CEA de Saclay; Gif-sur-Yvette France
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84
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Lin YT, Wu CTC, Cheng JH, Huang JL, Yeh KW. Patterns of sensitization to peanut allergen components in Taiwanese Preschool children. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2012; 45:90-5. [PMID: 22444546 DOI: 10.1016/j.jmii.2011.11.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 07/13/2011] [Accepted: 09/13/2011] [Indexed: 11/30/2022]
Abstract
BACKGROUND/PURPOSE Peanut allergy is very common in Western countries, although it is seldom encountered in Eastern countries. Peanuts are comprised of at least 11 components, but the contribution to clinical symptoms by each component in each individual is not known. This study investigated the distributions of sensitivity to peanut allergen components among Taiwanese children who were sensitized to peanuts and followed the evolution of sensitization patterns to these components. METHODS We enrolled 29 preschool children (age=2.11±1.36 years) who were sensitized to peanuts above class 3. Serum was analyzed for specific immunoglobulin E (IgE) antibodies to recombinant Ara h 1, Ara h 2, Ara h 3, Ara h 8, and Ara h 9. Allergen component-specific IgE ≥0.35 kU(A)/L was defined as positive. Eighteen children were retested 22.64±5.1 months later. Peanut allergy symptoms were recorded from detailed questionnaires. RESULTS The percentages of children sensitized to Ara h 1, 2, 3, 8, and 9 were, respectively, 51.8%, 65.5%, 62.1%, 13.8%, and 24.1%. Regarding changing patterns of peanut component sensitization at follow-up, children with clinical symptoms to peanuts had persistent elevations of Ara h 2-specific IgE: 12.6±1.01 up to 34.15±19.4 kU(A)/L; p=0.144. In contrast, Ara h 2 concentrations decreased significantly in children without clinical symptoms. Ara h 8 and 9 were nonspecific for children with or without symptoms. CONCLUSION Ara h 1, Ara h 2, and Ara h 3 were major components contributing to peanut sensitization in Taiwanese children. Ara h 2 was probably the most important component that contributed to clinical symptoms and remained steady in children who had peanut allergy.
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Affiliation(s)
- Yang-Te Lin
- Division of Allergy Asthma and Rheumatology, Department of Pediatrics, Chang Gung Memorial Hospital, Taoyuan, Taiwan
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85
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Abstract
PURPOSE OF REVIEW To review and discuss recent studies on molecular diagnosis of peanut and other legume allergy. RECENT FINDINGS Studies from the UK and France suggest that quantification of Ara h 2-specific IgE may accurately discriminate peanut allergy from tolerance. However, the pattern of allergenic component recognition in peanut-sensitized patients from different populations or geographical areas varies, reflecting different pollen and dietary exposures. In the USA, peanut-allergic patients are commonly sensitized to Ara h 1-3, in Spain to Ara h 9 and in Sweden to Ara h 8. Patients with soybean allergy sensitized to Gly m 5 or Gly m 6 allergens may be at greater risk of experiencing severe allergic reactions. SUMMARY Accurate diagnosis of peanut and legume allergy is challenging and essential. Measurement of IgE response to specific allergenic molecules may be more useful in predicting the presence and severity of clinical allergy than currently used skin or blood tests based on whole extracts. However, given the heterogeneity in component recognition patterns observed in different geographical areas, further studies are essential to identify and confirm potentially useful molecular diagnostic and prognostic markers. Until such markers are confirmed and replicated in different age groups, oral food challenge (OFC) remains the gold standard for accurate diagnosis.
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86
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Vissers YM, Blanc F, Skov PS, Johnson PE, Rigby NM, Przybylski-Nicaise L, Bernard H, Wal JM, Ballmer-Weber B, Zuidmeer-Jongejan L, Szépfalusi Z, Ruinemans-Koerts J, Jansen APH, Savelkoul HFJ, Wichers HJ, Mackie AR, Mills CEN, Adel-Patient K. Effect of heating and glycation on the allergenicity of 2S albumins (Ara h 2/6) from peanut. PLoS One 2011; 6:e23998. [PMID: 21901150 PMCID: PMC3162016 DOI: 10.1371/journal.pone.0023998] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Accepted: 07/29/2011] [Indexed: 11/19/2022] Open
Abstract
Background Peanut allergy is one of the most common and severe food allergies, and processing is known to influence the allergenicity of peanut proteins. We aimed to establish the effect of heating and glycation on the IgE-binding properties and biological activity of 2S albumins (Ara h 2/6) from peanut. Methodology/Principal Findings Native Ara h 2/6 was purified from raw peanuts and heated in solution (15 min, 110°C) in the presence or absence of glucose. Ara h 2 and 6 were also purified from roasted peanut. Using PBMC and sera from peanut-allergic patients, the cellular proliferative potency and IgE reactivity (reverse EAST inhibition) and functionality (basophil degranulation capacity) of allergens were assessed. Heating Ara h 2/6 at 110°C resulted in extensive denaturation, hydrolysis and aggregation of the protein, whilst Ara h 2 and 6 isolated from roasted peanut retained its native conformation. Allergen stimulation of PBMC induced proliferation and Th2 cytokine secretion which was unaffected by thermal processing. Conversely, IgE reactivity and functionality of Ara h 2/6 was decreased by heating. Whilst heating-glycation further reduced the IgE binding capacity of the proteins, it moderated their loss of histamine releasing capacity. Ara h 2 and 6 purified from roasted peanut demonstrated the same IgE reactivity as unheated, native Ara h 2/6. Conclusions/Significance Although no effect of processing on T-cell reactivity was observed, heat induced denaturation reduced the IgE reactivity and subsequent functionality of Ara h 2/6. Conversely, Ara h 2 and 6 purified from roasted peanut retained the structure and IgE reactivity/functionality of the native protein which may explain the allergenic potency of this protein. Through detailed molecular study and allergenicity assessment approaches, this work then gives new insights into the effect of thermal processing on structure/allergenicity of peanut proteins.
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Affiliation(s)
- Yvonne M Vissers
- Cell Biology and Immunology Group, Wageningen University and Research Centre, Wageningen, The Netherlands
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87
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Movérare R, Ahlstedt S, Bengtsson U, Borres MP, van Hage M, Poorafshar M, Sjölander S, Akerström J, van Odijk J. Evaluation of IgE antibodies to recombinant peanut allergens in patients with reported reactions to peanut. Int Arch Allergy Immunol 2011; 156:282-90. [PMID: 21720173 DOI: 10.1159/000323891] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 12/22/2010] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Peanut may cause severe reactions in allergic individuals. The objective was to evaluate IgE antibodies to various recombinant (r) peanut and birch pollen allergens in relation to IgE levels to whole peanut extract and severe allergic reactions to peanut. METHODS Seventy-four Swedish peanut-allergic patients (age: 14-61 years) reported previous peanut exposure and associated symptoms using a questionnaire. Their IgE reactivity to peanut, birch pollen and individual allergen components was analyzed using ImmunoCAP. RESULTS Of the 48 subjects sensitized to Ara h 1, 2 or 3, 60% had peanut-specific IgE levels >15 kU(A)/l, while 100% of the subjects without detectable IgE to these allergens had low peanut-specific IgE levels (<10 kU(A)/l). The levels of IgE to rAra h 8, rBet v 1 and birch pollen were highly correlated (r(S) = 0.94, p < 0.0001). Fifty-eight patients reported adverse reactions after accidental or deliberate peanut exposure (oral, inhalation or skin) of whom 41 had IgE to rAra h 1, 2 or 3. Symptoms of respiratory distress were associated with sensitization to Ara h 1, 2 or 3 (56 vs. 18%, p < 0.01). Two cases of anaphylaxis were reported among the individuals sensitized to Ara h 1-3. IgE to rAra h 8, rAra h 9, profilin or cross-reactive carbohydrate determinants were not associated with severe symptoms. CONCLUSIONS The results indicate that IgE reactivity to Ara h 1, 2 and 3 is associated with severe reactions after exposure to peanut in Swedish patients.
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88
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Koppelman SJ, Hefle SL, Taylor SL, de Jong GAH. Digestion of peanut allergens Ara h 1, Ara h 2, Ara h 3, and Ara h 6: a comparative in vitro study and partial characterization of digestion-resistant peptides. Mol Nutr Food Res 2011; 54:1711-21. [PMID: 20603832 DOI: 10.1002/mnfr.201000011] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
SCOPE There are differences in stability to pepsin between the major allergens in peanut; however, data are from different reports using different digestion models. This study provides a comprehensive comparison of the digestibility of the major peanut allergens. METHODS AND RESULTS Peanut allergens Ara h 1, Ara h 2, Ara h 3 and Ara h 6 were incubated with pepsin to mimic the effect of gastric digestion. Samples were analyzed using SDS-PAGE. To further investigate resistance to digestion, Ara h 2 was additionally subjected to digestion with trypsin and residual peptides were characterized. Ara h 1 and Ara h 3 were rapidly hydrolyzed by pepsin. On the contrary, Ara h 2 and Ara h 6 were resistant to pepsin digestion, even at very high concentrations of pepsin. In fact, limited proteolysis could only be demonstrated by SDS-PAGE performed under reducing conditions, indicating an important role for the disulfide bridges in maintaining the quaternary structure of Ara h 2 and Ara h 6. Trypsin digestion of Ara h 2 similarly resulted in large residual peptides and these were identified. CONCLUSION Ara h 2 and Ara h 6 are considerably more stable towards digestion than Ara h 1 and Ara h 3.
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89
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Differences among heat-treated, raw, and commercial peanut extracts by skin testing and immunoblotting. Ann Allergy Asthma Immunol 2011; 105:451-7. [PMID: 21130383 DOI: 10.1016/j.anai.2010.09.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 09/25/2010] [Accepted: 09/27/2010] [Indexed: 11/22/2022]
Abstract
BACKGROUND Peanut allergenicity has been reported to be influenced by heat treatment, yet the commonly available extracts for skin prick testing (SPT) are derived from raw extracts. OBJECTIVE To assess the effect of heat treatment on the SPT reactivity and specific IgE binding to peanut. METHODS Three commercial extracts and 3 laboratory-prepared extracts, including raw, roasted, and boiled, were used for SPT in 19 patients with suspected peanut allergy and in 4 individuals who eat peanut without any symptoms. Serum samples were obtained to measure total IgE in addition to specific IgE binding to the study extracts by immunoblotting. Peanut allergy was confirmed with challenge test unless the individual had a convincing history of a severe reaction. RESULTS Eleven study participants were considered peanut allergic based on a strong history or positive challenge test result. SPT with the prepared and commercial reagents showed that the boiled extract had the highest specificity (67% vs 42%-63% for the other extracts). The prepared extracts showed similar SPT sensitivity (81%). Three patients with a history of severe reaction and elevated specific IgE levels to peanut to the 3 study extracts had variable SPT reactivity to 1 or more of the commercial extracts. IgE binding to Ara h 2 was found in nearly all patients, regardless of their clinical reactivity. CONCLUSIONS None of the extracts tested showed optimal diagnostic reliability regarding both sensitivity and specificity. Perhaps testing should be performed with multiple individual extracts prepared by different methods.
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90
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Glaspole IN, de Leon MP, Prickett SR, O'Hehir RE, Rolland JM. Clinical allergy to hazelnut and peanut: identification of T cell cross-reactive allergens. Int Arch Allergy Immunol 2011; 155:345-54. [PMID: 21346364 DOI: 10.1159/000321268] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Accepted: 09/15/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Peanut and tree nut allergies are life-threatening conditions for many affected individuals worldwide. Currently there is no cure. While co-allergy to peanut and tree nuts is a common clinical observation, and IgE cross-reactivity between peanut and tree nuts is reported, T cell cross-reactivity is poorly defined. METHODS Hazelnut-specific T cell lines were established using peripheral blood mononuclear cells from 5 subjects with co-allergy to hazelnut and peanut. These lines were stimulated with hazelnut and peanut extracts and purified major peanut allergens, Ara h 1 and Ara h 2. Proliferation was determined by (3)H-thymidine incorporation and secretion of key Th1 (IFN-γ) and Th2 (IL-5) cytokines analysed by ELISA. RESULTS Hazelnut-specific T cell lines from all 5 subjects proliferated upon stimulation with both hazelnut and peanut extracts and for 4 subjects, to Ara h 1 and/or Ara h 2. Proliferating cells were mainly CD4+ T cells and produced both IL-5 and IFN-γ in response to hazelnut and peanut stimulation. Mitogenicity of extracts and allergens was excluded by their lack of stimulation of house dust mite-specific T cells. CONCLUSION Our finding that hazelnut and peanut co-allergy is associated with cross-reactive T cell responses, driven partly by cross-reactivity to the major peanut allergens Ara h 1 and Ara h 2, points to future development of allergen immunotherapy by targeting cross-reactive T cells.
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Affiliation(s)
- Ian N Glaspole
- Department of Allergy, Immunology and Respiratory Medicine, Alfred Hospital, Melbourne, Vic., Australia
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91
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Johnson PE, Van der Plancken I, Balasa A, Husband FA, Grauwet T, Hendrickx M, Knorr D, Mills ENC, Mackie AR. High pressure, thermal and pulsed electric-field-induced structural changes in selected food allergens. Mol Nutr Food Res 2010; 54:1701-10. [DOI: 10.1002/mnfr.201000006] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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92
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Radosavljevic J, Dobrijevic D, Jadranin M, Blanusa M, Vukmirica J, Cirkovic Velickovic T. Insights into proteolytic processing of the major peanut allergen Ara h 2 by endogenous peanut proteases. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2010; 90:1702-1708. [PMID: 20564442 DOI: 10.1002/jsfa.4005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
BACKGROUND The major peanut allergens are Ara h 1, Ara h 2 and Ara h 6. Proteolytic processing has been shown to be required for the maturation process of Ara h 6. The aim of this study was to examine whether Ara h 2 undergoes proteolytic processing and, if so, whether proteolytic processing influences its ability to bind human immunoglobulin E (IgE). RESULTS Ara h 2 isolated from peanut extract under conditions of protease inhibition revealed a single additional peak for its two known isoforms (Ara h 2.01 and Ara h 2.02), corresponding to a C-terminally truncated form lacking a dipeptide (RY). Ara h 2 isolated in the absence of protease inhibition, however, yielded two additional peaks, identified as C-terminally truncated forms lacking either a dipeptide (RY) or a single tyrosine residue. The IgE-binding capacity of the Ara h 2 truncated forms was not altered. CONCLUSION Ara h 2 undergoes proteolytic processing by peanut proteases that involves C-terminal removal of a dipeptide. Hence Ara h 2 isolated from peanut extract is a complex mixture of two isoforms expressed by different genes, Ara h 2.01 and Ara h 2.02, as well as truncated forms generated by the proteolytic processing of these isoforms.
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Affiliation(s)
- Jelena Radosavljevic
- Department of Biochemistry, Faculty of Chemistry, University of Belgrade, Studentski Trg 12-16, Belgrade, Serbia.
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93
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Flinterman AE, Pasmans SGMA, den Hartog Jager CF, Hoekstra MO, Bruijnzeel-Koomen CAFM, Knol EF, van Hoffen E. T cell responses to major peanut allergens in children with and without peanut allergy. Clin Exp Allergy 2010; 40:590-7. [PMID: 20067479 DOI: 10.1111/j.1365-2222.2009.03431.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND T cell responses involved in peanut allergy are poorly understood. OBJECTIVE To investigate T cell responses towards major peanut allergens in peanut-allergic (PA) subjects compared with peanut-sensitized (PS) non-allergic children and non-atopic (NA) controls. METHODS Eighteen PA children, seven non-allergic PS children and 11 NA adults were included. Peripheral blood mononuclear cells were stimulated with a crude peanut extract (CPE). Short-term T cell lines were generated and subsequently stimulated with CPE and purified Ara h 1, Ara h 2, Ara h 3 and Ara h 6. The proliferation and production of IL-13, IFN-gamma, IL-10 and TNF-alpha were analysed. RESULTS Proliferation to CPE and major allergens was enhanced in PA subjects. The primary response to CPE was comparable with PS subjects, with increased production of IL-13 and IFN-gamma compared with NA. Production of IL-10 was not observed. In short-term T cell lines, the response to CPE was stronger in PA than in PS and NA subjects. Only PA children had a detectable response to major peanut allergens, characterized by IL-13 production. The response was the highest after Ara h 3 stimulation, and the lowest after Ara h 2 stimulation. No significant correlation was observed between peanut-specific IgE levels and T cell responses to CPE. CONCLUSION T cell responses to CPE in PA and PS children were characterized by Th1 and Th2 cytokines. Only PA children showed enhanced Th2 responses to Ara h 1, Ara h 3 and Ara h 6.
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Affiliation(s)
- A E Flinterman
- Departments of Dermatology/Allergology, UMC Utrecht, The Netherlands
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94
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Lauer I, Dueringer N, Pokoj S, Rehm S, Zoccatelli G, Reese G, Miguel-Moncin MS, Cistero-Bahima A, Enrique E, Lidholm J, Vieths S, Scheurer S. The non-specific lipid transfer protein, Ara h 9, is an important allergen in peanut. Clin Exp Allergy 2009; 39:1427-37. [PMID: 19624524 DOI: 10.1111/j.1365-2222.2009.03312.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Plant food allergy in the Mediterranean area is mainly caused by non-specific lipid transfer proteins (nsLTP). The aim of this study was to characterize peanut nsLTP in comparison with peach nsLTP, Pru p 3, and assess its importance in peanut allergy. METHODS Peanut-allergic patients from Spain (n=32) were included on the basis of a positive case history and either a positive skin prick test or specific IgE to peanut. For comparison, sera of 41 peanut-allergic subjects from outside the Mediterranean area were used. Natural Ara h 9 and two isoforms of recombinant Ara h 9, expressed in Pichia pastoris, were purified using a two-step chromatographic procedure. Allergen characterization was carried out by N-terminal sequencing, circular dichroism (CD) spectroscopy, immunoblotting, IgE inhibition tests and basophil histamine release assays. RESULTS Compared with natural peanut nsLTP, the recombinant proteins could be purified in high amounts from yeast supernatant (> or =45 mg/L). The identity of the proteins was verified by N-terminal amino acid sequencing and with rabbit nsLTP-specific antibodies. CD spectroscopy revealed similar secondary structures for all preparations and Pru p 3. The Ara h 9 isoforms showed 62-68% amino acid sequence identity with Pru p 3. IgE antibody reactivity to rAra h 9 was present in 29/32 Spanish and 6/41 non-Mediterranean subjects. Recombinant Ara h 9 showed strong cross-reactivity to nPru p 3 and similar IgE-binding capacity as nAra h 9. The two Ara h 9 isoforms displayed similar IgE reactivity. In peanut-allergic patients with concomitant peach allergy, Ara h 9 showed a weaker allergenic potency than Pru p 3 in histamine release assays. CONCLUSIONS Ara h 9 is a major allergen in peanut-allergic patients from the Mediterranean area. Ara h 9 is capable of inducing histamine release from basophils, but to a lesser extent than Pru p 3.
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Affiliation(s)
- I Lauer
- Division of Allergology, Paul-Ehrlich-Institut, Langen, Germany.
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95
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Blanc F, Adel-Patient K, Drumare MF, Paty E, Wal JM, Bernard H. Capacity of purified peanut allergens to induce degranulation in a functional in vitro assay: Ara h 2 and Ara h 6 are the most efficient elicitors. Clin Exp Allergy 2009; 39:1277-85. [PMID: 19538351 DOI: 10.1111/j.1365-2222.2009.03294.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Peanut is a most common and potent food allergen. Many peanut allergens have been characterized using, in particular, IgE-binding studies. OBJECTIVES We optimized an in vitro functional assay to assess the capacity of peanut allergens to degranulate humanized rat basophilic leukaemia cells, RBL SX-38 cells, after sensitization by serum IgE from peanut-allergic patients. We thus compared the activity of the main peanut allergens, i.e. Ara h 1, Ara h 2, Ara h 3 and Ara h 6, purified from roasted peanut. METHODS Sera of 12 peanut-allergic patients were collected and total and peanut-specific IgE were measured. They were used to sensitize RBL SX-38 cells and the degranulation was induced by incubation with ranging concentrations of a whole peanut protein extract or of purified peanut allergens. The mediator release was quantified by the determination of beta-hexosaminidase activity in the supernatant. The intensity of the degranulation was expressed as maximum release and as EC50, corresponding to the dose of allergen that induced 50% of the maximum release. RESULTS For each serum, only 10 IU/mL of human IgE was necessary to sensitize the cells and obtain an optimal degranulation. With all the allergens, the release was positively correlated with the concentration of allergen-specific IgE in the serum used to sensitize the cells. The medians of EC50 obtained for Ara h 2 and Ara h 6 were 2.1 and 2.8 pm, respectively, while they were much higher for Ara h 3 and Ara h 1 (65 and 150 pm, respectively). CONCLUSION The RBL SX-38 release assay proved to be sensitive, specific and reproducible. It allowed the comparison of the degranulation potential of different peanut allergens. For all the sera tested, Ara h 2 and Ara h 6 were more potent than Ara h 1 or Ara h 3.
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Affiliation(s)
- F Blanc
- INRA, UR496, Unité d'Immuno-Allergie Alimentaire, Gif sur Yvette, Cedex, France
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96
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Porterfield HS, Murray KS, Schlichting DG, Chen X, Hansen KC, Duncan MW, Dreskin SC. Effector activity of peanut allergens: a critical role for Ara h 2, Ara h 6, and their variants. Clin Exp Allergy 2009; 39:1099-108. [PMID: 19438581 DOI: 10.1111/j.1365-2222.2009.03273.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
RATIONALE An important property of allergens is their ability to cross-link IgE and activate mast cells and basophils. The effector activity of peanut allergens has not been well characterized. METHODS Crude extracts of fresh peanut flour were fractionated by gel filtration. Effector function was assayed by measuring degranulation of RBL SX-38 cells sensitized with IgE from individual sera and from pools of sera of peanut-allergic donors. RESULTS Following gel filtration, 75 +/- 7% of the applied protein and 76 +/- 16% (n=3) of the applied activity (assayed with a pool of 11 sera) were recovered in the resultant fractions. The majority (85 +/- 2%; n=3) of the recovered activity resided in a fraction with a theoretical average molecular weight of approximately 20 kDa and a range of 13-25 kDa. When all the individual fractions were recombined, the measured activity was similar to that of the original extract [140 +/- 43% when measured with a pool of serum (n=2) and 66 +/- 7% when measured with individual sera (n=4)]; when all individual fractions excluding the 20 kDa fraction were recombined, the measured activity was only 8 +/- 2% (n=2) of the original extract when assayed with the serum pool and 10 +/- 4% (n=3) when assayed with the individual sera. Two-dimensional gel electrophoresis of this biologically active fraction revealed >60 protein spots. Analysis of 50 of the most prominent spots by matrix-assisted laser-desorption ionization time-of-flight mass spectrometry and of the full mixture by automated tandem mass spectrometry coupled to online capillary liquid chromatography revealed that >97% of the protein mass consisted of Ara h 2.0101, Ara h 2.0201, Ara h 6 isoforms, and variants of these proteins. CONCLUSIONS Ara h 2 and Ara h 6 account for the majority of the effector activity found in a crude peanut extract.
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Affiliation(s)
- H S Porterfield
- Department of Medicine, University of Colorado at Denver, Aurora, CO 80262, USA
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97
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Marsh J, Rigby N, Wellner K, Reese G, Knulst A, Akkerdaas J, van Ree R, Radauer C, Lovegrove A, Sancho A, Mills C, Vieths S, Hoffmann-Sommergruber K, Shewry PR. Purification and characterisation of a panel of peanut allergens suitable for use in allergy diagnosis. Mol Nutr Food Res 2009; 52 Suppl 2:S272-85. [PMID: 18727014 DOI: 10.1002/mnfr.200700524] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Peanut is a major cause of type 1 hypersensitive reactions including anaphylaxis. This results from the presence of a number of protein allergens, six of which are being studied as part of the EU FP6 EuroPrevall programme. These are Ara h 1 (7S globulin), Ara h 2, Ara h 6 (2S albumins), Ara h 3/4 (11S globulins) and Ara h 8 (Bet v 1 homologue). Methods for the purification of Ara h 1, Ara h 3/4, Ara h 2 and Ara h 6 from peanut seeds and for the production of recombinant Ara h 8 in Escherichia coli are described with spectroscopic analyses being used to confirm that they are authentically folded. N-terminal sequencing of the proteins purified from peanut seeds also revealed details of the differences between isoforms and their generation by proteolytic processing within the seed. Preliminary IgE binding studies of the purified allergens confirmed that they retained their immunological properties indicating their suitability for use in allergy diagnosis.
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Affiliation(s)
- Justin Marsh
- Rothamsted Research, Harpenden, Hertfordshire, UK
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98
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Chu Y, Faustinelli P, Ramos ML, Hajduch M, Stevenson S, Thelen JJ, Maleki SJ, Cheng H, Ozias-Akins P. Reduction of IgE binding and nonpromotion of Aspergillus flavus fungal growth by simultaneously silencing Ara h 2 and Ara h 6 in peanut. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:11225-11233. [PMID: 19007236 DOI: 10.1021/jf802600r] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The most potent peanut allergens, Ara h 2 and Ara h 6, were silenced in transgenic plants by RNA interference. Three independent transgenic lines were recovered after microprojectile bombardment, of which two contained single, integrated copies of the transgene. The third line contained multiple copies of the transgene. Ara h 2 expression was significantly suppressed in all three lines, whereas Ara h 6 was reduced in two lines. Expression of peanut allergens Ara h 1 and Ara h 3 was not noticeably affected. Significant reduction of human IgE binding to Ara h 2 and Ara h 6 also was observed. Seed weight and germination data from transgenic and nontransgenic segregants showed no significant differences. Data collected from in vitro Aspergillus flavus infection indicate no significant difference in fungal growth between the transgenic lines and the nontransgenic controls. These data suggest that silencing Ara h 2 and Ara h 6 is a feasible approach to produce hypoallergenic peanut.
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Affiliation(s)
- Ye Chu
- Department of Horticulture, University of Georgia, 31793, USA
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99
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Goodman RE. Performing IgE serum testing due to bioinformatics matches in the allergenicity assessment of GM crops. Food Chem Toxicol 2008; 46 Suppl 10:S24-34. [PMID: 18715545 DOI: 10.1016/j.fct.2008.07.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Proteins introduced into genetically modified (GM) organisms through genetic engineering must be evaluated for their potential to cause allergic disease under various national laws and regulations. The Codex Alimentarius Commission guidance document (2003) calls for testing of serum IgE binding to the introduced protein if the gene was from an allergenic source, or the sequence of the transferred protein has >35% identity in any segment of 80 or more amino acids to a known allergen or shares significant short amino acid identities. The Codex guidance recognized that the assessment will evolve based on new scientific knowledge. Arguably, the current criteria are too conservative as discussed in this paper and they do not provide practical guidance on serum testing. The goals of this paper are: (1) to summarize evidence supporting the level of identity that indicates potential risk of cross-reactivity for those with existing allergies; (2) to provide example bioinformatics results and discuss their interpretation using published examples of proteins expressed in transgenic crops; and (3) to discuss key factors of experimental design and methodology for serum IgE tests to minimize the rate of false negative and false positive identification of potential allergens and cross-reactive proteins.
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Affiliation(s)
- Richard E Goodman
- Food Allergy Research and Resource Program, Department of Food Science and Technology, University of Nebraska, 143 Food Industry Complex, Lincoln, USA.
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100
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Boulay A, Houghton J, Gancheva V, Sterk Y, Strada A, Schlegel-Zawadzka M, Sora B, Sala R, van Ree R, Rowe G. A EuroPrevall review of factors affecting incidence of peanut allergy: priorities for research and policy. Allergy 2008; 63:797-809. [PMID: 18588545 DOI: 10.1111/j.1398-9995.2008.01776.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Peanuts are extensively cultivated around the world, providing a foodstuff that is both cheap to produce and nutritious. However, allergy to peanuts is of growing global concern, particularly given the severity of peanut-allergic reactions, which can include anaphylaxis and death. Consequently, it is important to understand the factors related to the prevalence of peanut allergy in order to inform efforts to ameliorate or pre-empt the condition. In this article we review evidence for the relevance of factors hypothesized to have some association with allergy prevalence, including both genetic and environmental factors. Although our analysis does indicate some empirical support for the importance of a number of factors, the key finding is that there are significant data gaps in the literature that undermine our ability to provide firm conclusions. We highlight these gaps, indicating questions that need to be addressed by future research.
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Affiliation(s)
- A Boulay
- Institute of Food Research, Norwich Research Park, Colney, Norwich, UK
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