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Antigenicity of the proteins in soy lecithin and soy oil in soybean allergy
Author(s) -
Hiroko Awazuhara,
Hideki Kawai,
Baba M,
T Matsui,
Atsushi Komiyama
Publication year - 1998
Publication title -
clinical and experimental allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 154
eISSN - 1365-2222
pISSN - 0954-7894
DOI - 10.1046/j.1365-2222.1998.00431.x
Subject(s) - soy protein , antigenicity , soybean oil , chemistry , lecithin , food science , soybean proteins , chromatography , immunoglobulin e , plant lipid transfer proteins , biochemistry , biology , antibody , immunology , gene
Background Soy lecithin and soy oil are usually produced from the hexane extract of soybean. Some of the soybean proteins are included in the extract and are therefore present in small amounts in both soy lecithin and soy oil. The antigenicity of the proteins present in defatted soybean has been studied with respect to soybean allergy, but the antigenicity of those found in the extract is yet to be investigated. Objective The antigenicity of soy lecithin and soy oil proteins with regard to soybean allergy were investigated. Methods The proteins present in soy lecithin and soy oil were determined according to already established method and analysed by SDS‐PAGE. The IgE‐ and IgG4‐binding abilities of the soy lecithin proteins were investigated by immunoblotting with sera from 30 soybean‐sensitive patients, including seven with a positive challenge test. Immunoblotting of soy oil proteins was performed with the sera from some of these patients. Results In 100 g of sample, the soy lecithin and soy oil contained 2.8 mg and 1.4–4.0 μg of proteins, respectively. The results of SDS‐PAGE demonstrated the presence of only three proteins, with molecular weights of about 58–67 kDa in soy oil, and suggested that soy lecithin also contains these proteins. The soy lecithin also contained many proteins besides these. In the soy lecithin, the detection rate of only one protein, with a molecular weight of 31 kDa, by the serum IgE of patients was significantly different compared with controls (detection rate: 40%). The proteins with molecular weights of 58–67 kDa rarely bound to serum IgE. Only one of the patients who presented a positive challenge test had IgE antibodies to soy lecithin proteins. IgG4‐binding proteins were found only rarely in soy lecithin. Neither the IgE nor the IgG4 present in the patients' sera reacted to any soy oil protein. Conclusion Proteins present in soy lecithin and soy oil have little antigenicity with regard to soybean allergy.