Germin-like protein Cit s 1 and profilin Cit s 2 are major allergens in orange (Citrus sinensis) fruits

• Published in: Molecular nutrition & food research Vol. 50; no. 3; pp. 282 - 290
• Main Authors: Crespo, Jesus F., Retzek, Mechthild, Foetisch, Kay, Sierra-Maestro, Elena, Cid-Sanchez, Ana B., Pascual, Cristina Y., Conti, Amedeo, Feliu, Angelica, Rodriguez, Julia, Vieths, Stefan, Scheurer, Stephan
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.03.2006; WILEY‐VCH Verlag; Wiley-VCH-Verl
• Subjects: Allergens - analysis; Allergens - chemistry; Antigens, Plant; Basophils - drug effects; Basophils - physiology; Biological and medical sciences; Citrus sinensis; Citrus sinensis - immunology; Food Hypersensitivity - immunology; Food industries; Fruit - immunology; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; General aspects; Germin-like protein; Glycoproteins - analysis; Humans; Immunoglobulin E - blood; Immunoglobulin E - immunology; Isoflavone reductase-like protein; Methods of analysis, processing and quality control, regulation, standards; Orange allergy; Peptide Fragments - chemistry; Plant Proteins - analysis; Profilin; Profilins - analysis; Isoflavone; min-like protein / Isoflavone reductase-like protein / Orange allergy / Profilin; Immunopathology; Allergy; Fruit; Citrus sinensis; Enzyme; Citrus fruit; Rutaceae; Flavonoid; Orange; Protein; Phytoestrogen; Polyphenol; Dicotyledones; Angiospermae; Spermatophyta; Oxidoreductases; Allergen; Reductase
• ISSN: 1613-4125; 1613-4133
• DOI: 10.1002/mnfr.200500200

Oranges are clinically relevant allergenic foods. To date, orange allergens have not been characterized in detail. The study is aimed at analyzing the sensitization profile in orange‐sensitized subjects with and without clinical allergy, and to identify orange allergens. Fifty‐six sensitized subjects with self‐reported reactions to orange were grouped into reactors (anaphylaxis or multiple episodes of immediate reactions and/or positive challenge tests) and non‐reactors (negative open food challenge tests). Allergens were characterized by IgE immunoblotting, N‐terminal sequencing, IgE‐inhibition assays, and mediator release assays were performed to determine the allergenic potency of orange profilin. Of 56 subjects, 23 were classified as orange allergic showing mainly an oral allergy syndrome. Of 23 subjects classified as orange allergic, 22 were sensitized to profilin, Cit s 2. In patients with mono‐sensitization to profilin in vitro histamine releases up to 75% from basophils were induced using orange extract and purified plant profilins. Of the allergic patients 78% were sensitized to germin‐like protein, Cit s 1. Both allergens showed retained IgE reactivity in heat‐processed orange juice. Interestingly, subjects with and without clinical allergy showed a comparable sensitization profile. Profilin and germin‐like proteins are major orange allergens. The potential clinical relevance of orange profilin was indicated by its strong capacity to release histamine from basophils. However, a predominant sensitization to both allergens in subjects without symptoms also indicates a high frequency of clinically insignificant sensitization.