Milk whey protein fed as a constituent of the diet induced both oral tolerance and a systemic humoral response, while heat-denatured whey protein induced only oral tolerance.

Milk whey protein fed to mice as a constituent of the diet elicited a systemic humoral response. The serum antibodies were of the IgG class, which recognized mainly beta-lactoglobulin. Feeding whey protein diet also induced tolerance of systemic immunity (oral tolerance). However, when heat-denatured whey protein was fed, the animals showed only a poor serum response, while oral tolerance was induced to a similar degree as that of native whey protein diet. The results demonstrate the difference of antigen recognition between oral tolerance and oral immunization and suggests that our system using mice may be a useful animal model for food allergy.