Characterization of the Soluble Allergenic Proteins of Cashew Nut (Anacardium occidentale L.)

• Published in: Journal of agricultural and food chemistry Vol. 50; no. 22; pp. 6543 - 6549
• Main Authors: Teuber, Suzanne S, Sathe, Shridhar K, Peterson, W. Rich, Roux, Kenneth H
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Washington, DC American Chemical Society 23.10.2002
• Subjects: Adult; Agronomy. Soil science and plant productions; Anacardium - adverse effects; Anacardium - chemistry; Anacardium - immunology; Antigens, allergens; Biological and medical sciences; Blotting, Western; Electrophoresis, Polyacrylamide Gel; Female; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Fundamental immunology; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; Generalities. Production, biomass, yield. Quality; Humans; Hypersensitivity, Immediate - immunology; Immediate hypersensitivity. Allergy. Anaphylaxis, etc; Immunobiology; Immunoglobulin E - chemistry; Immunoglobulin E - immunology; Male; Middle Aged; Molecular Weight; Nut Hypersensitivity; Plant Proteins - adverse effects; Plant Proteins - analysis; Plant Proteins - immunology; Solubility; Storage protein; 2S albumin; Anacardium occidentale; IgE; Identification; Soluble form; Allergenicity; Globulin; Characterization; Binding protein; legumin-like protein; Dicotyledones; Angiospermae; N terminal-Sequence; Fruit tree; sucrose-binding protein; Aminoacid sequence; Anacardiaceae; Cashew; Albumin; vicilin; food allergy; 13S globulin; tree nut allergy; anacardein; FOOD ALLERGIES; Plant protein; Spermatophyta; Legumin; Cashew nut; Allergen
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf025757j

The allergens associated with cashew food allergy have not been well-characterized. We sought to identify the major allergens in cashew nut by performing IgE immunoblots to dissociated and reduced or nonreduced cashew protein extracts, followed by sequencing of the peptides of interest. Sera from 15 subjects with life-threatening reactions to cashews and 8 subjects who tolerate cashews but have life-threatening reactions to other tree nuts were compared. An aqueous cashew protein extract containing albumin/globulin was separated by sodium dodecyl sulfate−polyacrylamide gel electrophoresis (SDS−PAGE) and subjected to IgE immunoblotting using patient sera. Selected IgE reactive bands were subjected to N-terminal amino acid sequencing. Each of the 15 sera from cashew-allergic subjects showed IgE binding to the cashew protein extract. The dominant IgE-binding antigens in the reduced preparations included peptides in the 31−35 kD range, consistent with the large subunits of the major storage 13S globulin (legumin-like protein). Low-molecular-weight polypeptides of the 2S albumin family, with similarity to the major walnut allergen Jug r 1, also bound IgE. The sera from eight patients who tolerate cashew but displayed allergies to other tree nuts showed only minimal or no IgE binding to cashew. Cashew food allergy is associated with the presence of IgE directed against the major seed storage proteins in cashew, including the 13S globulin (legumin group) and 2S albumins, both of which represent major allergen classes in several plant seeds. Thus, the legumin-group proteins and 2S albumins are again identified as major food allergens, which will help further research into seed protein allergenicity. Keywords: Cashew; 13S globulin; legumin-like protein; 2S albumin; vicilin; sucrose-binding protein; anacardein; food allergy; tree nut allergy