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Mameri H, Snégaroff J, Gohon Y, Pecquet C, Choudat D, Raison-Peyron N, Denery-Papini S, Wien F, Briozzo P. Immunoglobulin-E reactivity and structural analysis of wheat low-molecular-weight glutenin subunits and their repetitive and nonrepetitive halves. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:7538-7547. [PMID: 22747247 DOI: 10.1021/jf3007568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The IgE reactivity of the recombinant glutenin subunits P73 and B16, and of their repetitive N-terminal and nonrepetitive C-terminal halves, was analyzed using dot-blot with sera from patients diagnosed with baker's asthma, wheat-dependent exercise-induced anaphylaxis, or allergy to hydrolyzed wheat proteins. The linear epitopes of B16 were identified using the Pepscan method. Except for one common epitope, the IgE binding domains of glutenins differ from those of ω5-gliadins. Secondary structure content of the proteins was determined using synchrotron radiation circular dichroism (SRCD): while α structures were predominant in all glutenin subunits, fragments, or chimeras, a high IgE reactivity was associated with proteins rich in β structures. Mixing B16 halves induced conformational interaction, as evidenced by dynamic light scattering and SRCD. IgE reactivity was correlatively increased, as when the halves were associated in the B16-P73 chimera. These results suggest that structural interaction between N- and C-terminal halves may promote epitope presentation.
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Affiliation(s)
- Hamza Mameri
- INRA, UMR 1318 Institut Jean-Pierre Bourgin, F-78026 Versailles, France
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52
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Kulis M, Macqueen I, Li Y, Guo R, Zhong XP, Burks AW. Pepsinized cashew proteins are hypoallergenic and immunogenic and provide effective immunotherapy in mice with cashew allergy. J Allergy Clin Immunol 2012; 130:716-23. [PMID: 22795369 DOI: 10.1016/j.jaci.2012.05.044] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 05/01/2012] [Accepted: 05/23/2012] [Indexed: 12/19/2022]
Abstract
BACKGROUND IgE-mediated allergic reactions to cashews and other nuts can trigger life-threatening anaphylaxis. Proactive therapies to decrease reaction severity do not exist. OBJECTIVES We aimed to determine the efficacy of pepsin-digested cashew proteins used as immunotherapy in a murine model of cashew allergy. METHODS Mice were sensitized to cashew and then underwent challenges with digested or native cashew allergens to assess the allergenicity of the protein preparations. Using native or pepsinized cashew proteins, mice underwent oral or intraperitoneal sensitization protocols to determine the immunogenic properties of the protein preparations. Finally, cashew-sensitized mice underwent an immunotherapy protocol with native or pepsinized cashew proteins and subsequent provocation challenges. RESULTS Pepsinized cashew proteins elicited weaker allergic reactions than native cashew proteins but importantly retained the ability to stimulate cellular proliferation and cytokine production. Mice sensitized with pepsinized proteins reacted on challenge with native allergens, demonstrating that pepsinized allergens retain immunogenicity in vivo. Immunotherapy with pepsinized cashew allergens significantly decreased allergic symptoms and body temperature decrease relative to placebo after challenge with native and pepsinized proteins. Immunologic changes were comparable after immunotherapy with native or pepsinized allergens: T(H)2-type cytokine secretion from splenocytes was decreased, whereas specific IgG(1) and IgG(2a) levels were increased. CONCLUSIONS Pepsinized cashew proteins are effective in treating cashew allergy in mice and appear to work through the same mechanisms as native protein immunotherapy.
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Affiliation(s)
- Mike Kulis
- Department of Pediatric Allergy and Immunology, Duke University Medical Center, Durham, NC 27710, USA.
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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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Bøgh KL, Barkholt V, Rigby NM, Mills ENC, Madsen CB. Digested Ara h 1 loses sensitizing capacity when separated into fractions. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:2934-2942. [PMID: 22364549 DOI: 10.1021/jf2052306] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The major peanut allergen Ara h 1 is an easily digestible protein under physiological conditions. The present study revealed that pepsin digestion products of Ara h 1 retained the sensitizing potential in a Brown Norway rat model, while this sensitizing capacity was lost by separating the digest into fractions by gel permeation chromatography. Protein chemical analysis showed that the peptide composition as well as the aggregation profiles of the fractions of Ara h 1 digest differed from that of the whole pool. These results indicate that the sensitizing capacity of digested Ara h 1 is a consequence of the peptides being in an aggregated state resembling the intact molecule or that most peptides of the digests need to be present in the same solution, having a synergistic or adjuvant effect and thereby augmenting the immune response against other peptides.
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Affiliation(s)
- Katrine L Bøgh
- National Food Institute, Division of Toxicology and Risk Assessment, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark.
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55
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Ayuso R, Sánchez-Garcia S, Pascal M, Lin J, Grishina G, Fu Z, Ibáñez MD, Sastre J, Sampson HA. Is epitope recognition of shrimp allergens useful to predict clinical reactivity? Clin Exp Allergy 2011; 42:293-304. [PMID: 22192087 DOI: 10.1111/j.1365-2222.2011.03920.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 09/19/2011] [Accepted: 10/11/2011] [Indexed: 11/28/2022]
Abstract
BACKGROUND Shrimp is a frequent cause of severe allergic reactions world-wide. Due to issues such as cross-reactivity, diagnosis of shrimp allergy is still inaccurate, requiring the need for double-blind, placebo-controlled food challenges (DBPCFC). A better understanding of the relationship between laboratory findings and clinical reactivity is needed. OBJECTIVE To determine whether sensitization to certain shrimp allergens or recognition of particular IgE epitopes of those allergens are good biomarkers of clinical reactivity to shrimp. METHODS Thirty-seven consecutive patients were selected with clinical histories of shrimp allergy. Skin prick test, specific IgE determinations, DBPCFC and immunoblot assays to shrimp extract were performed. IgE binding to synthetic overlapping peptides representing the sequence of the four allergens from the Pacific white shrimp (Litopenaeus vannamei) identified to date (Lit v1, Lit v2, Lit v3 and Lit v4) was analysed. RESULTS Of 37 (46%) patients, 17 had a positive challenge to shrimp (11 children and 6 adults). By microarray, patients with positive challenges showed more intense binding to shrimp peptides than those with negative challenges. Statistically significant differences in terms of the frequency and intensity of IgE binding to some epitopes were observed between the two groups. Diagnostic efficiency was higher for individual epitopes than for proteins. Particularly, efficiency was highest for certain Lit v 1 and Lit v 2 epitopes, followed by Lit v 3 and Lit v 4 epitopes. CONCLUSION AND CLINICAL RELEVANCE Patients with positive shrimp challenges present in general more intense and diverse epitope recognition to all four shrimp allergens. IgE antibodies to these shrimp epitopes could be used as biomarkers for prediction of clinical reactivity in subjects with sensitization to shrimp. Patients with positive shrimp challenges show more intense sensitization and more diverse epitope recognition. Several IgE-binding shrimp epitopes could be used as biomarkers for predicting clinical reactivity in subjects with sensitization to shrimp.
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Affiliation(s)
- R Ayuso
- Division of Allergy & Immunology, Mount Sinai School of Medicine, New York, NY 10029, USA.
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56
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Protein unfolding strongly modulates the allergenicity and immunogenicity of Pru p 3, the major peach allergen. J Allergy Clin Immunol 2011; 128:1022-30.e1-7. [DOI: 10.1016/j.jaci.2011.04.020] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 03/15/2011] [Accepted: 04/05/2011] [Indexed: 01/03/2023]
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Rosenfeld L, Shreffler W, Bardina L, Niggemann B, Wahn U, Sampson HA, Beyer K. Walnut allergy in peanut-allergic patients: significance of sequential epitopes of walnut homologous to linear epitopes of Ara h 1, 2 and 3 in relation to clinical reactivity. Int Arch Allergy Immunol 2011; 157:238-45. [PMID: 22042002 DOI: 10.1159/000327841] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 03/25/2011] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Peanut allergy is a frequent and potentially life-threatening food allergy. Despite the large taxonomic distance between the plants, peanut-allergic patients often react to tree nuts such as walnuts. While the allergens of peanut and walnut have a high degree of homology in their amino-acid sequences, it is unknown whether this similarity is responsible for the observed co-reactivity. Therefore, we analyzed the binding of specific IgE antibodies to sequential epitopes of peanut and walnut in peanut-allergic patients with and without walnut allergy. METHODS The IgE binding to previously described sequential epitopes of peanut and the homologous regions of walnut was assessed in 32 peanut-allergic patients using a peptide microarray technology. Twelve patients had a clinically relevant walnut allergy and 20 were tolerant to walnut. Inhibition assays with peanut peptides and corresponding walnut sequences were performed to show specific binding to sequential epitopes. RESULTS No differences in the recognition of sequential epitopes could be found between peanut-allergic patients with or without walnut allergy. Only a few patients showed IgE binding to walnut sequences that corresponded to sequential epitopes of peanut. In the inhibition assays, no relevant cross-reacting IgE antibodies could be detected for the peptides analyzed. CONCLUSION Our results indicate that although they share a rather high degree of homology with the corresponding regions of walnut allergens, the sequence stretches previously identified as sequential IgE binding epitopes of Ara h 1, Ara h 2 and Ara h 3 have no IgE binding equivalents in walnut allergens.
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Affiliation(s)
- Leonard Rosenfeld
- Department of Pediatric Pneumology and Immunology, University Children's Hospital Charité, Berlin, Germany
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58
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Abstract
Here, we discuss various questions related to IgE epitopes: What are the technical possibilities and pitfalls, what is currently known, how can we put this information into hypothetical frameworks and the unavoidable question: how useful is this information for patient care or allergenicity prediction? We discuss the information obtained by (i) 3D structures of allergen-antibody complexes; (ii) analysis of allergen analogues; (iii) mimics without obvious structural similarity; (iv) mAbs competing with IgE; (v) repertoire analysis of cloned IgEs, and other developments. Based on limited data, four suggestions are presented in the literature: (i) IgE might be more cross-reactive than IgG; (ii) IgE might be more often directed to immunologically 'uninviting' surfaces; (iii) IgE epitopes may tend to cluster and (iv) IgE paratopes might have a higher intrinsic flexibility. While these are not proven facts, they still can generate hypotheses for future research. The hypothesis is put forward that the IgE repertoire of switched B-cells is less influenced by positive selection, because positive selection might not be able to rescue IgE-switched B cells. While this might be of interest for the discussion about mechanisms leading to allergen-sensitization, we need to be modest in answering the 'clinical relevance' question. Current evidence indicates the IgE-epitope repertoire is too big to make specific IgE epitopes a realistic target for diagnosis, treatment or allergenicity prediction. In-depth analysis of a few selected IgE epitope-peptides or mimitopes derived from allergen-sequences and from random peptide libraries, respectively, might well prove rewarding in relation to diagnosis and prognosis of allergy, particularly food allergy.
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Affiliation(s)
- R C Aalberse
- Department of Immunopathology, Sanquin Research and Academic Medical Centre, Amsterdam, the Netherlands.
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59
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Denery-Papini S, Bodinier M, Pineau F, Triballeau S, Tranquet O, Adel-Patient K, Moneret-Vautrin DA, Bakan B, Marion D, Mothes T, Mameri H, Kasarda D. Immunoglobulin-E-binding epitopes of wheat allergens in patients with food allergy to wheat and in mice experimentally sensitized to wheat proteins. Clin Exp Allergy 2011; 41:1478-92. [PMID: 21771117 DOI: 10.1111/j.1365-2222.2011.03808.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND At present, B cell epitopes involved in food allergy to wheat are known only for a few allergens and a few categories of patients. OBJECTIVE To characterize the epitopes of different wheat kernel allergens: α-, γ, ω2, and ω5-gliadin, a low-molecular-weight (LMW) glutenin subunit, and a lipid transfer protein (LTP1) recognized by allergic patients and by sensitized mice and provide further understanding of the role of structure in determining allergic response. METHODS Sera were obtained from 39 patients suffering from food allergy to wheat. BALB/c mice were sensitized to gliadins or LTP1 by intraperitoneal immunizations. Continuous epitopes bound by IgE were delineated by the Pepscan technique. The response to reduced, alkylated LTP1 was compared with that of the native form to evaluate the importance of protein folding on IgE reactivity. RESULTS Few continuous epitopes of LTP1 reacted with IgE from allergic patients and mice, but one of them was common to several patients and sensitized mice. The unfolded protein was not recognized by either patient or mouse IgE, emphasizing the major role of LTP1 folding and discontinuous epitopes in IgE-binding. In contrast, many continuous epitopes were detected by patient and mouse IgE especially for an ω5-gliadin, which is an unstructured protein, and to a lesser extent, for the other gliadins and a LMW-glutenin subunit. CONCLUSION AND CLINICAL RELEVANCE The conformation of LTP1 appeared to have a strong impact on the type of IgE-binding epitopes elicited by this protein in both man and mouse. The responses in mice sensitized to gliadins or LTP1 were sufficiently comparable with the human response in terms of IgE-binding epitopes to provide support for the use of the mouse model in further investigations.
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Affiliation(s)
- S Denery-Papini
- INRA, UR1268 Biopolymers, Interactions, Assemblies, rue de la Géraudière, Nantes cedex 03, France.
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60
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Mueller GA, Gosavi RA, Pomés A, Wünschmann S, Moon AF, London RE, Pedersen LC. Ara h 2: crystal structure and IgE binding distinguish two subpopulations of peanut allergic patients by epitope diversity. Allergy 2011; 66:878-85. [PMID: 21255036 DOI: 10.1111/j.1398-9995.2010.02532.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Peanut allergy affects 1% of the population and causes the most fatal food-related anaphylactic reactions. The protein Ara h 2 is the most potent peanut allergen recognized by 80-90% of peanut allergic patients. METHODS The crystal structure of the major peanut allergen Ara h 2 was determined for the first time at 2.7 Å resolution using a customized maltose-binding protein (MBP)-fusion system. IgE antibody binding to the MBP fusion construct vs the natural allergen was compared by ELISA using sera from peanut allergic patients. RESULTS The structure of Ara h 2 is a five-helix bundle held together by four disulfide bonds and related to the prolamin protein superfamily. The fold is most similar to other amylase and trypsin inhibitors. The MBP--Ara h 2 fusion construct was positively recognized by IgE from 76% of allergic patients (25/33). Two populations of patients could be identified. Subpopulation 1 (n = 14) showed an excellent correlation of IgE antibody binding to natural vs recombinant Ara h 2. Subpopulation 2 (n = 15) showed significantly reduced IgE binding to the MBP fusion protein. Interestingly, about 20% of the IgE binding in subpopulation 2 could be recovered by increasing the distance between MBP and Ara h 2 in a second construct. DISCUSSION The reduced IgE binding to the MBP--Ara h 2 of subpopulation 2 indicates that the MBP molecule protects an immunodominant epitope region near the first helix of Ara h 2. Residues involved in the epitope(s) are suggested by the crystal structure. The MBP--Ara h 2 fusion constructs will be useful to further elucidate the relevance of certain epitopes to peanut allergy.
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MESH Headings
- 2S Albumins, Plant/chemistry
- 2S Albumins, Plant/genetics
- 2S Albumins, Plant/immunology
- 2S Albumins, Plant/metabolism
- Antigens, Plant/chemistry
- Antigens, Plant/genetics
- Antigens, Plant/immunology
- Antigens, Plant/metabolism
- Arachis/genetics
- Arachis/immunology
- Arachis/metabolism
- Crystallization
- Crystallography, X-Ray
- Glycoproteins/chemistry
- Glycoproteins/genetics
- Glycoproteins/immunology
- Glycoproteins/metabolism
- Humans
- Immunodominant Epitopes/chemistry
- Immunodominant Epitopes/genetics
- Immunodominant Epitopes/immunology
- Immunoglobulin E/immunology
- Immunoglobulin E/metabolism
- Maltose-Binding Proteins/chemistry
- Maltose-Binding Proteins/genetics
- Maltose-Binding Proteins/metabolism
- Models, Molecular
- Peanut Hypersensitivity/classification
- Peanut Hypersensitivity/diagnosis
- Peanut Hypersensitivity/immunology
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
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Affiliation(s)
- G A Mueller
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA.
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61
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Willison LN, Tripathi P, Sharma G, Teuber SS, Sathe SK, Roux KH. Cloning, expression and patient IgE reactivity of recombinant Pru du 6, an 11S globulin from almond. Int Arch Allergy Immunol 2011; 156:267-81. [PMID: 21720172 DOI: 10.1159/000323887] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Accepted: 12/26/2010] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND IgE-reactive proteins have been identified in almond; however, few have been cloned and tested for specific patient IgE reactivity. Here, we clone and express prunin 1 and prunin 2, isoforms of the major almond protein prunin, an 11S globulin, and assay each for IgE reactivity. METHODS Prunin isoforms were PCR-amplified from an almond cDNA library, sequenced, cloned and expressed in Escherichia coli. Reactivity to the recombinant (r) allergens, Pru du 6.01 and Pru du 6.02, was screened by dot blot and immunoblot assays using sera from almond-allergic patients and murine monoclonal antibodies (mAbs). Sequential IgE-binding epitopes were identified by solid-phase overlapping peptide analysis. Epitope stability was assessed by assaying denatured recombinant proteins by immunoblot. RESULTS IgE reactivity to rPru du 6.01 and rPru du 6.02 was found in 9 of 18 (50%) and 5 of 18 patients (28%), respectively. Four patients (22%) demonstrated reactivity to both isoforms. Murine anti-almond IgG mAbs also showed greater reactivity to rPru du 6.01 than to rPru du 6.02. Both stable and labile epitopes were detected. Six IgE-binding sequential epitope-bearing peptide segments on Pru du 6.01 and 8 on Pru du 6.02 were detected using pooled almond-allergic sera. CONCLUSIONS rPru du 6.01 is more widely recognized than rPru du 6.02 in our patient population. The identification of multiple sequential epitopes and the observation that treatment with denaturing agents had little effect on IgE-binding intensity in some patients suggests an important role for sequential epitopes on prunins.
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Affiliation(s)
- LeAnna N Willison
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4295, USA
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Su CF, Kuo IC, Chen PW, Huang CH, Seow SV, Chua KY, Yu SM. Characterization of an immunomodulatory Der p 2-FIP-fve fusion protein produced in transformed rice suspension cell culture. Transgenic Res 2011; 21:177-92. [DOI: 10.1007/s11248-011-9518-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2010] [Accepted: 04/26/2011] [Indexed: 11/29/2022]
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63
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Lollier V, Denery-Papini S, Larré C, Tessier D. A generic approach to evaluate how B-cell epitopes are surface-exposed on protein structures. Mol Immunol 2010; 48:577-85. [PMID: 21111484 PMCID: PMC7112657 DOI: 10.1016/j.molimm.2010.10.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 10/24/2010] [Indexed: 11/17/2022]
Abstract
Methods that predict antibody epitopes could help to promote the development of diagnostic tools, vaccines or immunotherapies by affecting the epitope binding of antibodies during an immunological response to antigens. It is generally assumed that there is a direct relationship between antibody accessibility to antigens and accessible surface of proteins. Based on this assumption, prediction systems often includes solvent accessibility values calculated from the primary sequence of proteins or from their three dimensional structures as a predictive criterion. However, the current prediction systems seem weakly efficient in view of benchmark tests. We were interested in evaluating how amino acids that have been experimentally identified as epitopic elements could differ from the rest of the antigenic molecule at the level of surface exposure, hence we assessed the average accessibility of epitopes. The approach used here utilises published epitopes deduced from numerous identification techniques, including sequence scanning and structure visualisation after crystallography, and it involves many types of antigens from toxins to allergens. Our results show that epitopic residues are not distributed among any specific Relative Surface Accessibility and Protrusion Index values and that, in some cases, epitopes cover the entire antigenic sequence. These results led to the conclusion that the classification of known epitopes with respect to the experimental conditions used to identify them should be introduced before attempting to characterise epitopic areas in a generic way.
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Affiliation(s)
- Virginie Lollier
- UR1268 Biopolymers, Interactions, Assemblies, INRA, 44300 Nantes, France.
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64
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Prickett SR, Voskamp AL, Dacumos-Hill A, Symons K, Rolland JM, O'Hehir RE. Ara h 2 peptides containing dominant CD4+ T-cell epitopes: candidates for a peanut allergy therapeutic. J Allergy Clin Immunol 2010; 127:608-15.e1-5. [PMID: 21093025 DOI: 10.1016/j.jaci.2010.09.027] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 08/26/2010] [Accepted: 09/23/2010] [Indexed: 11/30/2022]
Abstract
BACKGROUND Peanut allergy is a life-threatening condition; there is currently no cure. Although whole allergen extracts are used for specific immunotherapy for many allergies, they can cause severe reactions, and even fatalities, in peanut allergy. OBJECTIVE This study aimed to identify short, T-cell epitope-based peptides that target allergen-specific CD4(+) T cells but do not bind IgE as candidates for safe peanut-specific immunotherapy. METHODS Multiple CD4(+) T-cell lines specific for the major peanut allergen Ara h 2 were generated from PBMCs of 16 HLA-diverse subjects with peanut allergy by using 5,6-carboxyfluorescein diacetate succinimidylester-based methodology. Proliferation and ELISPOT assays were used to identify dominant epitopes recognized by T-cell lines and to confirm recognition by peripheral blood T cells of epitope-based peptides modified for therapeutic production. HLA restriction of core epitope recognition was investigated by using anti-HLA blocking antibodies and HLA genotyping. Serum-IgE peptide-binding was assessed by dot-blot. RESULTS Five dominant CD4(+) T-cell epitopes were identified in Ara h 2. In combination, these were presented by HLA-DR, HLA-DP, and HLA-DQ molecules and recognized by T cells from all 16 subjects. Three short peptide variants containing these T-cell epitopes were designed with cysteine-to-serine substitutions to facilitate stability and therapeutic production. Variant peptides showed HLA-binding degeneracy, did not bind peanut-specific serum IgE, and could directly target T(H)2-type T cells in peripheral blood of subjects with allergy. CONCLUSION Short CD4(+) T-cell epitope-based Ara h 2 peptides were identified as novel candidates for a T-cell-targeted peanut-specific immunotherapy for an HLA-diverse population.
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Affiliation(s)
- Sara R Prickett
- Department of Immunology, Monash University, Melbourne, Australia
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65
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Dupont D, Mandalari G, Mollé D, Jardin J, Rolet-Répécaud O, Duboz G, Léonil J, Mills CEN, Mackie AR. Food processing increases casein resistance to simulated infant digestion. Mol Nutr Food Res 2010; 54:1677-89. [DOI: 10.1002/mnfr.200900582] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Abstract
PURPOSE OF REVIEW To highlight recent advances in management of peanut allergy. RECENT FINDINGS Peanut allergy presents during early childhood. The prevalence of peanut allergy in children in developed countries appears to be increasing. Several factors, such as peanut-specific or environmental, are hypothesized as contributing to increased prevalence. However, there is no consensus on this matter. Component-related diagnostic tests are being explored to characterize clinical sensitivity. Currently, the primary treatment includes avoidance of peanut and immediate treatment of anaphylaxis. Recent peanut oral immunotherapy (OIT) trials achieved successful desensitization to peanuts in study participants, which may benefit many patients. Newer prospective studies are exploring effects of early high-dose peanut protein introduction versus avoidance in high-risk infants and development of peanut tolerance [Learning Early About Peanut Allergy (LEAP) study]. Several other immunotherapeutic approaches are being investigated in animal models. SUMMARY There is no cure for peanut allergy. Peanut oral immunotherapy offers a potential treatment for desensitization.
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Affiliation(s)
- Milind Pansare
- Division of Allergy/Immunology, Wayne State University, and Pediatric Residency Program, The Carman and Ann Adams Department of Pediatrics, Children's Hospital of Michigan, Detroit, Michigan 48201, USA.
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67
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Robotham JM, Xia L, Willison LN, Teuber SS, Sathe SK, Roux KH. Characterization of a cashew allergen, 11S globulin (Ana o 2), conformational epitope. Mol Immunol 2010; 47:1830-8. [PMID: 20362336 DOI: 10.1016/j.molimm.2009.12.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 12/11/2009] [Accepted: 12/17/2009] [Indexed: 10/19/2022]
Abstract
Both linear and conformational epitopes likely contribute to the allergenicity of tree nut allergens, yet, due largely to technical issues, few conformational epitopes have been characterized. Using the well studied recombinant cashew allergen, Ana o 2, an 11S globulin or legumin, we identified a murine monoclonal antibody which recognizes a conformational epitope and competes with patient IgE Ana o 2-reactive antibodies. This epitope is expressed on the large subunit of Ana o 2, but only when associated with an 11S globulin small subunit. Both Ana o 2 and the homologous soybean Gly m 6 small subunits can foster epitope expression, even when the natural N-terminal to C-terminal subunit order is reversed in chimeric molecules. The epitope, which is also expressed on native Ana o 2, is readily susceptible to destruction by physical and chemical denaturants.
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Affiliation(s)
- Jason M Robotham
- Department of Biological Science and Institute of Molecular Biophysics, Florida State University, 319 Stadium Dr., Tallahassee, FL 32306-4295, USA
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Sicherer SH, Leung DYM. Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects in 2009. J Allergy Clin Immunol 2010; 125:85-97. [PMID: 20109740 DOI: 10.1016/j.jaci.2009.11.031] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 11/23/2009] [Indexed: 11/15/2022]
Abstract
This review highlights some of the research advances in anaphylaxis and hypersensitivity reactions to foods, drugs, and insects, as well as advances in allergic skin disease that were reported in the Journal in 2009. Among key epidemiologic observations, several westernized countries report that more than 1% of children have peanut allergy, and there is some evidence that environmental exposure to peanut is a risk factor. The role of regulatory T cells, complement, platelet-activating factor, and effector cells in the development and expression of food allergy were explored in several murine models and human studies. Delayed anaphylaxis to mammalian meats appears to be related to IgE binding to the carbohydrate moiety galactose-alpha-1,3-galactose, which also has implications for hypersensitivity to murine mAb therapeutics containing this oligosaccharide. Oral immunotherapy studies continue to show promise for the treatment of food allergy, but determining whether the treatment causes tolerance (cure) or temporary desensitization remains to be explored. Increased baseline serum tryptase levels might inform the risk of venom anaphylaxis and might indicate a risk for mast cell disorders in persons who have experienced such episodes. Reduced structural and immune barrier function contribute to local and systemic allergen sensitization in patients with atopic dermatitis, as well as increased propensity of skin infections in these patients. The use of increased doses of nonsedating antihistamines and potential usefulness of omalizumab for chronic urticaria was highlighted. These exciting advances reported in the Journal can improve patient care today and provide insights on how we can improve the diagnosis and treatment of these allergic diseases in the future.
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Affiliation(s)
- Scott H Sicherer
- Elliot and Roslyn Jaffe Food Allergy Institute, Division of Allergy and Immunology, Department of Pediatrics, Mount Sinai School of Medicine, New York, NY, USA.
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