Kiwifruit protease Act d 1 compromises the intestinal barrier by disrupting tight junctions

Background Actinidin (Act d 1) is a cysteine protease and major allergen of kiwifruit with diagnostic significance. It is the most abundant of the 11 kiwifruit allergens recognized and has been identified as a marker molecule of kiwifruit allergy. However, the mechanism underlining the oral route of exposure and sensitization to this allergen has yet to be elucidated. Working under the hypothesis that food proteases, as was shown for some inhalatory allergenic proteases, could reach the intestinal mucosa and surpass this barrier through proteolytic activity, we examined the following: Does Act d 1 have the ability to resist gastrointestinal digestion and reach the intestinal mucosa in a biologically active form? Upon reaching the intestinal mucosa does Act d 1 enhance permeability of the intestinal barrier by disrupting tight junctions?