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Characterization of the antigenic specificity of soybean protein β-conglycinin and its effects on growth and immune function in rats

2007; Taylor & Francis; Volume: 61; Issue: 3 Linguagem: Inglês

10.1080/17450390701318358

1745-039X

Pengfei Guo, Xiangshu Piao, Deyuan Ou, Defa Li, Yue Hao,

Mast cells and histamine

Abstract The objective of the present study was to characterize the antigenic specificity of purified soybean β-conglycinin and to investigate its effects on the growth and immune responses of rats. Thirty-two Brown Norway rats, 3 weeks of age, were randomly allotted to one of four treatments and individually fed casein-cornstarch based diets. Rats were sensitised by means of intragastric gavage with purified β-conglycinin (0, 5, 10 or 20 mg protein/ml in phosphate buffered saline at pH 7.4) on day 0, 7, 14, and 21 (1 ml/animal). On day 28, rats received a double dose of β-conglycinin. Blood was obtained at weekly intervals after initiation of challenge. Growth declined linearly with increasing the concentration of soybean β-conglycinin (p < 0.05). Both the total IgE and β-conglycinin-specific IgE levels in serum increased while passive cutaneous anaphylactic reactions were induced in the rats. Lymphocyte proliferation response to concanavalin A in plasma and spleen was increased linearly with increased levels of soybean (p < 0.01) β-conglycinin. The percentage of CD4+ lymphocyte subset linearly increased (p < 0.001). As a result, the concentrations of cytokines in plasma and spleen, including interleukin-4 (p < 0.01), interleukin-5 (p < 0.01), and tumour necrosis factor-α (p < 0.01) increased linearly with increasing level of purified β-conglycinin. Our results indicate that purified β-conglycinin possesses intrinsic immune-stimulating capacity and can induce an allergic reaction. Therefore, dietary soybean β-conglycinin has negative effects on growth and both cell-mediated and humoral immune function in rats.