Guo Pengfei, Piao Xiangshu, Cao Yunhe, Ou Deyuan, Li Defa
National Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, PR China.
Int Arch Allergy Immunol. 2008;145(2):102-10. doi: 10.1159/000108135. Epub 2007 Sep 7.
The major storage protein in soybean seed is beta-conglycinin and this protein has been identified as being responsible for food-allergic reactions in several species. However, the mechanism through which beta-conglycinin induces an allergic reaction has not yet been elucidated. In addition, assessing the antigenic activity of beta-conglycinin by studying the activity of a subunit has rarely been conducted. Therefore, the objective of the present study was to characterize the antigenic specificity of the beta-conglycinin alpha'-subunit.
We established an Escherichia coli expression system to obtain beta-conglycinin alpha'-subunit. The fusion proteins were then used in a rat model to induce a hypersensitive reaction. Immunoblotting, IgE and IgG1 level, histamine release, and passive cutaneous anaphylaxis reactions and intestinal histology were tested to assess the allergenic activity of the beta-conglycinin alpha'-subunit.
Pure beta-conglycinin alpha'-subunit was obtained by expression in E. coli. The recombinant proteins were shown to have the same biological activity as the natural beta-conglycinin alpha'-subunit using immunoblotting analysis. Both the IgE and IgG1 level in serum and the histamine concentration in the intestine were increased while passive cutaneous anaphylactic reactions were induced in Brown Norway rats by intragastric gavage with the alpha'-subunit. Histamine release of mast cells was also elevated in vitro.
Our results indicate that the beta-conglycinin alpha'-subunit possesses an intrinsic immune-stimulating capacity and that it can induce an allergic reaction. Moreover, this study showed that beta-conglycinin alpha'-subunit-induced anaphylaxis is IgE mediated, and mast cell degranulation and histamine release are associated with anaphylactic symptoms.
大豆种子中的主要贮藏蛋白是β-伴大豆球蛋白，该蛋白已被确定是多种物种食物过敏反应的原因。然而，β-伴大豆球蛋白诱导过敏反应的机制尚未阐明。此外，通过研究亚基活性来评估β-伴大豆球蛋白的抗原活性的研究很少。因此，本研究的目的是表征β-伴大豆球蛋白α'-亚基的抗原特异性。
我们建立了一个大肠杆菌表达系统来获得β-伴大豆球蛋白α'-亚基。然后将融合蛋白用于大鼠模型以诱导过敏反应。通过免疫印迹、IgE和IgG1水平、组胺释放、被动皮肤过敏反应和肠道组织学检测来评估β-伴大豆球蛋白α'-亚基的致敏活性。
通过在大肠杆菌中表达获得了纯的β-伴大豆球蛋白α'-亚基。使用免疫印迹分析表明重组蛋白具有与天然β-伴大豆球蛋白α'-亚基相同的生物活性。用α'-亚基灌胃棕色挪威大鼠后，血清中的IgE和IgG1水平以及肠道中的组胺浓度均升高，同时诱导了被动皮肤过敏反应。体外肥大细胞的组胺释放也升高。
我们的结果表明，β-伴大豆球蛋白α'-亚基具有内在的免疫刺激能力，并且可以诱导过敏反应。此外，本研究表明β-伴大豆球蛋白α'-亚基诱导的过敏反应是由IgE介导的，肥大细胞脱颗粒和组胺释放与过敏症状有关。
