Comparison of sensitization between beta-lactoglobulin and its hydrolysates

Bovine beta-lactoglobulin is one of the first foreign antigens encountered by some newborn children, and it has been described as the main allergenic protein in cow's milk even when present at low concentration.

Enzymatic hydrolysis has been identified to be a very effective way to reduce the sensitization of beta-lg compared to other treatments. The aim of this study was to explore whether enzymatic hydrolysis could reduce the allergenicity of native bovine beta-lg.

beta-lg was hydrolyzed by trypsin. Twenty four BALB/c mice were divided into three groups and orally sensitized by native bovine beta-lg and its hydrolysates five times at weekly intervals.

During the sensitization period, many serious systemic anaphylactic symptoms were observed in mice sensitized by native beta-lg compared to hydrolysates of beta-lg. Mice sensitized by hydrolysates of beta-lg showed a significantly lower spleen lymphocyte proliferation level than intact beta-lg. The beta-lg-specific IgE antibody levels in serum and intestinal fluid samples induced by native beta-lg were significantly elevated. Plasma histamine levels were also evaluated and showed the same trend as IgE. Moreover, the hydrolysates of beta-lg significantly up-regulated IFN-gamma and IL-10 production and down-regulated IL-4 and IL-5 secretions by murine splenocytes.

These results suggested that enzymatic hydrolysis could partly reduce the allergenicity of beta-lg.