Evaluation of allergenic potential for rice seed protein components utilizing a rice proteome database and an allergen database in combination with IgE-binding of recombinant proteins.

Among 131 rice endosperm proteins previously identified by MS-based proteomics, most of the proteins showed low or almost no sequence similarity to known allergens in databases, whereas nine proteins did it significantly. The sequence of two proteins showed high overall identity with Hsp70-like hazel tree pollen allergen (Cor a 10) and barley α-amylase (Hor v 16), respectively, whereas the others showed low identity (28-58%) with lemon germin-like protein (Cit l 1), corn zein (Zea m 50 K), wheat chitinase-like xylanase inhibitor (Tri a XI), and kinase-like pollen allergen of Russian thistle (Sal k 1). Immuno-dot blot analysis showed that recombinant proteins for these rice seed homologs were positive in the IgE-binding, but not necessarily similarity dependent, from some allergic patients. These results suggest that utilization of proteome and sequence databases in combination with IgE-binding analysis was effective to screen and evaluate allergenic potential of rice seed protein components.