Background For genetically predisposed atopic infants, cow's milk protein hydrolysed formulas have been widely used.
Objective Whether hydrolysed formulas can induce oral tolerance to whey proteins will be extensively studied in naïve and sensitized mice.
Methods Antigenicity of hydrolysed formulas was first studied using immunoblotting. Naïve mice fed hydrolysed formulas for 1–4 weeks were sensitized with whey allergens. In contrast, mice sensitized with whey allergens were fed hydrolysed formulas continually for 12 weeks.
Results Whey allergens were found in Nan and Neoangelac FL. Large whey peptides with antigenicity were found in Nan-HA. Profound suppression of IgE, IgG1 and IgG responses to whey allergens were induced in those fed Nan for 1 week, or Nan-HA for 4 weeks. IgE responses to whey allergens were suppressed in those fed Neoangelac FL for 4 weeks, or Nan-HA for 1–2 weeks. In contrast, those fed extensively hydrolysed formulas for 1–4 weeks failed to show decreased responses. On the other hand, IgE responses to β-lactoglobulin, but not to bovine serum albumin or α-lactalbumin, were decreased in sensitized mice fed Nan for 12 weeks. There was no suppression in sensitized mice fed hydrolysed formulas.
Conclusion Suppression of IgE responses to whey proteins was readily induced in naïve mice fed Nan or Nan-HA for 1 week. In contrast, it was hardly induced in sensitized mice even after prolonged feeding of Nan for 12 weeks, let alone hydrolysed formulas.