RESUMO
This study evaluated the effects of gamma-radiation on the antigenic properties of beta-lactoglobulin in cow's milk. Liquid and lyophilized samples of cow's milk and whey were irradiated with gamma-cells (60Co) at dose levels of 3, 5, and 10 kGy, at room temperature in the presence of air. Effects of treatment on proteins were monitored by Lowry's method, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and enzyme-linked immunosorbent assay. Radiation did not affect the molecular-weight distributions of proteins, but it did reduce their solubility. Furthermore, results showed that irradiation at 10 kGy increased the recognition of milk and whey powders by anti-beta-lactoglobulin (beta-Lg) rabbit immunoglobulin G, with the other samples remaining antigenically stable. These results indicate that gamma-rays do not reduce cow's milk beta-lactoglobulin antigenicity.
Assuntos
Irradiação de Alimentos , Raios gama , Lactoglobulinas/imunologia , Lactoglobulinas/efeitos da radiação , Hipersensibilidade a Leite/prevenção & controle , Leite , Animais , Bovinos , Relação Dose-Resposta à Radiação , Eletroforese em Gel de Poliacrilamida/métodos , Ensaio de Imunoadsorção Enzimática/métodos , Humanos , Imunoglobulina G/imunologia , Imunoglobulina G/efeitos da radiação , Leite/imunologia , Leite/efeitos da radiação , SolubilidadeRESUMO
Weaning is a transient period of life during which maternal proteins are replaced by foreign proteins. Concomitantly, in early postnatal life, both digestive and immune systems undergo a maturation process. Allergy to cow's milk protein may develop in human infants during weaning, determining digestive, respiratory, cutaneous or systemic symptoms. We studied the intestinal response to bovine milk beta-lactoglobulin (beta-LG) in infants with cow's milk allergy, first during the active phase, and then during the symptom-free stage. During the active phase, transepithelial transport of the beta-LG across the intestinal epithelial layer stimulated the sensitized subepithelial immune cells. This stimulation induced a rise in short-circuit current suggestive of an electrogenic chloride secretion and impaired protein handling by the epithelium. These findings underline the dual role of the epithelial layer in intestinal function: on one hand, it takes an active part in allowing dietary antigens to stimulate the submucosal system, and on the other hand becomes the target for mediators involved in food allergy.