The Mechanism of Whey Protein Hydrolysates with Oral Immunotolerance

To investigate the mechanism of oral immune tolerance induced by whey protein hydrolysates, this study utilized five industrially used proteases to hydrolyze whey protein and prepared the hydrolysates. An oral immune tolerance model was established using Balb/c mice. The levels of specific IgG, IgE, and histamine in the serum of mice from the five hydrolysate-preventive groups were measured. The expression levels of genes and proteins associated with the MAPK signaling pathway in small intestinal mast cells were analyzed using qPCR and Western blot. The results demonstrated that the expression of JNK in the jejunum from the trypsin, bromelain, papain, Neutrase, and pepsin mouse groups was downregulated, which correlated with the alleviation of allergic responses. A moderate increase in ERK expression was accompanied by an expansion of Treg cells, thereby inducing oral immune tolerance. The process of oral immune tolerance was regulated by the MAPK signaling pathway. This study systematically elucidates the oral immune tolerance mechanisms of the five hydrolysates, and the conclusions will provide the guidance for the development of hypoallergenic infant formula.