2S methionine-rich protein (SSA) from sunflower seed is an IgE-binding protein.
BACKGROUND
Sunflower seed contains 2S albumins that in other crops have been associated with allergenicity. The sunflower seed methionine-rich 2S albumin (SSA) may be an IgE-binding protein responsible for anaphylactic reactions in some sunflower seed-sensitive subjects. The objective was to demonstrate that SSA is an IgE-binding protein.


METHODS
SSA was purified and the amino-acid sequence determined. The degree of purity of SSA was evaluated by silver staining, and its IgE-binding capacity by immunoblotting with serum from a subject with a convincing clinical history of anaphylaxis to sunflower seed.


RESULTS
The amino-acid sequence confirmed that the purified protein was the mature form of the methionine-rich storage protein SSA from sunflower seed (Helianthus annuus). The SSA was specifically recognized by IgE from the serum of the sunflower seed-allergic subject.


CONCLUSIONS
SSA is an IgE-binding protein, and subjects allergic to sunflower seed whose IgE binds to SSA are at risk of developing allergic reactions if they consume SSA.
Kelly
J D
JD
Food Allergy Research and Resource Program, University of Nebraska at Lincoln, 68583-0919, USA.
Hefle
S L
SL
D055516:2S Albumins, Plant; D000485:Allergens / Q000276:immunology; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D004591:Electrophoresis, Polyacrylamide Gel; D005512:Food Hypersensitivity / Q000276:immunology; D006801:Humans; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000276:immunology*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010940:Plant Proteins / Q000276:immunology* / Q000302:isolation & purification; D012639:Seeds / Q000276:immunology; D016622:Silver Staining
D055516:2S Albumins, Plant; D000485:Allergens; D052179:Antigens, Plant; D010940:Plant Proteins; C067568:methionine-rich 2S protein, Helianthus; D007073:Immunoglobulin E