The objective of the present study was to characterize the antigenic specificity of purified soybean beta-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 beta-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 beta-conglycinin. Blood was obtained at weekly intervals after initiation of challenge. Growth declined linearly with increasing the concentration of soybean beta-conglycinin (p