Hydrolysate of highly digestible phosphorylated buckwheat major allergen Fag e 2 attenuates allergic reactions in Fag e 2-sensitized mice

Abstract

Fag e 2 is a 16 kDa major buckwheat allergen that is highly resistant to pepsin digestion. We previously reported that phosphorylation reduced the IgE-binding activity of Fag e 2 and oral administration of phosphorylated Fag e 2 (P-Fag e 2) attenuated allergic reactions in mice. In this study, we investigated the effects of phosphorylation on the digestibility of Fag e 2 and assessed whether digested P-Fag e 2 (DP-Fag e 2) can attenuate allergic reactions in Fag e 2-sensitized mice. Recombinant Fag e 2, obtained using the Pichia expression system, was phosphorylated via dry-heating in the presence of pyrophosphate. The peptic digestibility of Fag e 2 was enhanced by phosphorylation. Mice orally administered DP-Fag e 2 for 6 weeks after Fag e 2 sensitization exhibited reduced allergic symptom scores compared to those of sham-treated mice. Furthermore, decreased total and specific IgE, decreased specific IgG₁, and increased total IgA were observed in the serum of the DP-Fag e 2-fed group. These results suggest that P-Fag e 2 is easily digested in the stomach and induces the attenuation of the IgE-mediated allergic reaction.