Comparison of sensitization between β-lactoglobulin and its hydrolysates
Background: Bovine β-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.
Objective: Enzymatic hydrolysis has been identified to be a very effective way to reduce the sensitization of β-lg compared to other treatments. The aim of this study was to explore whether enzymatic hydrolysis could reduce the allergenicity of native bovine β-lg.
Methods: β-lg was hydrolyzed by trypsin. Twenty four BALB/c mice were divided into three groups and orally sensitized by native bovine β-lg and its hydrolysates five times at weekly intervals.
Results: During the sensitization period, many serious systemic anaphylactic symptoms were observed in mice sensitized by native β-lg compared to hydrolysates of β-lg. Mice sensitized by hydrolysates of β-lg showed a significantly lower spleen lymphocyte proliferation level than intact β-lg. The β-lg-specific IgE antibody levels in serum and intestinal fluid samples induced by native β-lg were significantly elevated. Plasma histamine levels were also evaluated and showed the same trend as IgE. Moreover, the hydrolysates of β-lg significantly up-regulated IFN-γ and IL-10 production and down-regulated IL-4 and IL-5 secretions by murine splenocytes.
Conclusion: These results suggested that enzymatic hydrolysis could partly reduce the allergenicity of β-lg.