Gastrointestinal digestion and absorption of soybean β-conglycinin in an early weaned piglet model: An initial step to the induction of soybean allergy.

To date, it still remains unknown how β-conglycinin, a major soybean allergen, crosses intestinal epithelial barrier to reach immune cells. The purpose of this study was to elucidate the pathway and molecular mechanism of β-conglycinin absorption and transport across intestinal mucosal epithelium using a β-conglycinin allergic piglet model. Ten-day old piglets were orally sensitized with diets containing 2% and 4% β-conglycinin. The digestion, absorption and transport of β-conglycinin in gastrointestinal tract was investigated. The results showed that β-conglycinin had a certain resistance to gastrointestinal digestion, and the digestion-resistant subunits and fragments were absorbed into the intestinal mucosa and then induced an anaphylaxis in early weaned piglets. The absorption occurred in the form of IgE-allergen immune complex through transcellular pathway with CD23 as the receptor. These results provided important clues for using the pathway and molecule as inhibitor target to prevent and alleviate soybean β-conglycinin allergy in infants.