Analysis of the Structural and Immunological Stability of 2S Albumin, Nonspecific Lipid Transfer Protein, and Profilin Allergens from Mustard Seeds

Departamento de Bioquímica y Biología Molecular, Facultad de Química, Universidad Complutense de Madrid, Ciudad Universitaria, 28040 Madrid, Spain.
Journal of Agricultural and Food Chemistry (Impact Factor: 2.91). 05/2012; 60(23). DOI: 10.1021/jf300555h
Source: PubMed


This work investigates the resistance to proteolysis and heating of the yellow mustard (Sinapis alba L.) allergens Sin a 1 (2S albumin), Sin a 3 (nonspecific lipid transfer protein, LTP), and Sin a 4 (profilin) to explain their potential capability to induce primary sensitization at the gastrointestinal level. Sin a 1 and Sin a 3 resisted gastric digestion showing no reduction of the IgE reactivity. Intestinal digestion of Sin a 1 and Sin a 3 produced a limited proteolysis but retained significant IgE-binding reactivity. Sin a 1 was stable after heating, and although Sin a 3 was modified, most of its structure was recovered after cooling back. These two allergens would be therefore able to sensitize by ingestion. Sin a 4 was completely digested by gastric treatment and its conformational structure markedly modified at 85 °C. Thus, this allergen can be described as a nonsensitizing mustard allergen.

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    • "In accordance with this finding, CD measurement of Cor a 14 revealed that the protein retained most of its secondary structure after heating and completely refolded after cooling. This was also shown for other 2S albumins [37] [38]. "
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    ABSTRACT: Allergens from nuts frequently induce severe allergic reactions in sensitive individuals. The aim of this study was to elucidate the physicochemical characteristics of natural Cor a 14, the 2S albumin from hazelnut. Cor a 14 was purified from raw hazelnuts using a combination of precipitation and chromatographic techniques. The protein was analyzed using gel electrophoresis, mass spectrometry, and far-UV circular dichroism (CD) analyses. The IgE binding of native, heat-treated, and in vitro digested Cor a 14 was studied. We identified two different Cor a 14-isoforms and showed microclipping at the C-terminus. CD spectra at room temperature showed the typical characteristics of 2S albumins, and temperatures of more than 80°C were required to start unfolding of Cor a 14 demonstrating its high stability to heat treatment. In vitro digestion experiments revealed that Cor a 14 is resistant to proteolytic degradation. Native and heat-treated protein was recognized by sera from hazelnut allergic patients. However, denaturation of the allergen led to significantly reduced IgE binding. We identified two different isoforms of Cor a 14 displaying high stability under heating and gastric and duodenal conditions. Data from IgE binding experiments reveal the existence of both, linear and conformational epitopes. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Full-text · Article · Jul 2015 · Molecular Nutrition & Food Research
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    • "Four allergens from yellow mustard seeds have been identified, purified and characterized so far: i) 2S albumin Sin a 1 (14 kDa) [10,11]; ii) 11S globulin Sin a 2 (51 kDa) [12,13]; iii) LTP Sin a 3 (12 kDa) [14]; and iv) profilin Sin a 4 (13–14 kDa) [14]. Sin a 1 and Sin a 3 but not Sin a 4 might act as genuine food allergens able to reach the gut immune system due to their high structural and immunological stability [15]. The capacity of Sin a 2 to act as primary sensitizer at the intestinal mucosa has not been investigated so far. "
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    ABSTRACT: Background The 11S globulin Sin a 2 is a marker to predict severity of symptoms in mustard allergic patients. The potential implication of Sin a 2 in cross-reactivity with tree nuts and peanut has not been investigated so far. In this work, we studied at the IgG and IgE level the involvement of the 11S globulin Sin a 2 in cross-reactivity among mustard, tree nuts and peanut. Methods Eleven well-characterized mustard-allergic patients sensitized to Sin a 2 were included in the study. A specific anti-Sin a 2 serum was obtained in rabbit. Skin prick tests (SPT), enzyme-linked immunosorbent assay (ELISA), immunoblotting and IgG or IgE-inhibition immunoblotting experiments using purified Sin a 2, Sin a 1, Sin a 3, mustard, almond, hazelnut, pistachio, walnut or peanut extracts were performed. Results The rabbit anti-Sin a 2 serum showed high affinity and specificity to Sin a 2, which allowed us to demonstrate that Sin a 2 shares IgG epitopes with allergenic 11S globulins from tree nuts (almond, hazelnut, pistachio and walnut) but not from peanut. All the patients included in the study had positive skin prick test to tree nuts and/or peanut and we subdivided them into two different groups according to their clinical symptoms after ingestion of such allergenic sources. We showed that 11S globulins contain conserved IgE epitopes involved in cross-reactivity among mustard, tree nuts and peanut as well as species-specific IgE epitopes. Conclusions The allergenic 11S globulin Sin a 2 from mustard is involved in cross-reactivity at the IgE level with tree nuts and peanut. Although the clinical relevance of the cross-reactive IgE epitopes present in 11S globulins needs to be investigated in further detail, our results contribute to improve the diagnosis and management of mustard allergic patients sensitized to Sin a 2.
    Full-text · Article · Dec 2012
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    ABSTRACT: Immunoglobulin (Ig) E-mediated food allergy is a type 2 helper T cell (TH2)-dependent disease whose prevalence is increasing in industrialized countries as a direct consequence of reduced tolerance to food antigens. The generation of regulatory T cells (Treg) is a key component of oral tolerance, and compelling experimental evidence has demonstrated that functional allergen-specific Treg cells play a major role in healthy immune responses to allergens and clinically successful allergen-specific immunotherapy. In the particular case of IgE-mediated food allergy, further investigations are required to firmly demonstrate the role of Treg cells during desensitization, induction of tolerance, or both, and several studies have also suggested a key role for these cells in healthy responses to food allergens. Treg cells are able to suppress the sensitization and effector phases of allergic reactions via several mechanisms of action based on multiple soluble and surface-binding molecules. Our knowledge of the mechanisms governing the generation of food allergen-specific Treg cells in the gastrointestinal mucosa, including the specific dendritic cell subsets involved in such processes, has increased significantly over the last decade. The identification of alternative tissues where oral tolerance to food allergens might occur in vive is crucial, not only for a better understanding of the pathophysiology of food allergy, but also for the development of alternative therapeutic interventions. Recent findings demonstrate that oral tolerance can be induced in the tonsils through generation and maintenance of functional allergen-specificTreg cells. Further investigation in this area could pave the way for novel treatments of food allergy and other immune tolerance-related diseases.
    No preview · Article · Jan 2013 · Journal of investigational allergology & clinical immunology: official organ of the International Association of Asthmology (INTERASMA) and Sociedad Latinoamericana de Alergia e Inmunología
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