Effects of various saccharides on the masking of epitope sites and uptake in the gut of cedar allergen Cry j 1-saccharide conjugates by a naturally occurring Maillard reaction.

A major allergen of Japanese cedar, Cry j 1, was conjugated with galactomannan (M(w) of 15 kDa), dextran (M(w) of 12 kDa), xyloglucan (M(w) of 1.4 kDa), and various monosaccharides through the Maillard reaction by dry-heating in 65% relative humidity. The Cry j 1-galactomannan conjugate completely masked the epitopes of the allergen in Cry j 1. The Cry j 1-dextran conjugate also masked the epitopes of Cry j 1. The small size of oligosaccharide (xyloglucan) and various monosaccharides cannot mask the epitopes of allergen Cry j 1. This suggests that the higher molecular size of attached saccharides is important to mask sterically the epitope sites. The Cry j 1-galactomannan and Cry j 1-mannose conjugates were effectively trafficked in the gut and co-localized with immune cells, such as dendritic cells in the gut, suggesting that Cry j 1-saccharide conjugates are phagocytosed via the mannose receptor in immune cells. These results suggest that the Cry j 1-galactomannan conjugate is suitable for masking the epitope sites of Cry j 1 and trafficking to immune cells in gut lumen.