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.

抄録全体を表示

Fag e 1 is a 22 kDa globulin found in common buckwheat (Fagopyrum esculentum) and it is known to be one of the major allergens causing severe allergic symptoms. In this study, we successfully obtained recombinant Fag e 1 using the Pichia expression system and prepared an allergen-specific hypoallergenic agent by the controlled dry-heating phosphorylation of Fag e 1 (P-Fag e 1). Then, we investigated if P-Fag e 1 can be useful as an immunomodulator in Fag e 1-sensitized mice. For this, P-Fag e 1 was orally administrated into Fag e 1-sensitized mice for 6 weeks, and then these mice were challenged with Fag e 1. We observed a significant reduction in the histamine release in addition to diminished production of total as well as specific IgE in the P-Fag e 1-treated mice. In contrast, total IgA level increased by the treatment with P-Fag e1. The levels of the IL-4 cytokines from both spleen and Peyer’s patches were significantly decreased in P-Fag e 1 treated mice. Additionally, the population of T follicular helper cells (Tfh cells) was increased in the P-Fag e 1 treated group. The suppression of IgE production in the Fag e1 treated group might be due to the enrichment of the Tfh cells and IgA production. Therefore, it could be proposed that P-Fag e 1 is an allergen-specific immunomodulator in mice allergic to Fag e 1.

抄録全体を表示