Modulation of immunoresponse in BALB/c mice by oral administration of Fag e 1-glucomannan conjugate.

Maillard-type glycosylation was applied to preparation of hypoallergenic agents from a major buckwheat allergen, Fag e 1. Conjugation with arabinogalactan (AG), xyloglucan (XG), or yeast glucomannan (YGM) successfully decreased in vitro allergenicity of Fag e 1. Determination of IgE titer in the tested allergic mice revealed that YGM was the most effective for in vivo allergenicity of Fag e 1 among these water-soluble polysaccharides. Real-time PCR analysis using a set of primer for IL-4 (a typical Th2 cytokine) or IFN-gamma (a typical Th1 cytokine) showed that expressed mRNA for IL-4 in splenocytes drastically decreased with increasing with Fag e 1-YGM conjugate feeding. In addition, based on a flow-cytometric analysis of T cell subsets in the splenocytes, it was confirmed that the feeding led to an improvement of Th1/Th2 balance in the allergic mice where population of Th1 increased from 2.91% to 4.02%, while that of Th2 decreased from 3.75% to 2.72%. Furthermore, it was revealed that differentiation ratio of regulatory T cell (Treg) in the splenocytes increased from 14.5% to 18.7% by the oral administration. These results indicated that Fag e 1-YGM conjugate can be available for an immunomodulating agent for buckwheat allergy.