Molecular Properties of Plant Food Allergens: A Current Classification into Protein Families

So far the allergen list of the International Union of Immunological Societies (IUIS) allergen nomenclature subcommittee comprises 130 plant-derived food allergens. Based on sequence homology these allergens can be classified into only 27 out of 9,000 known protein families according to the Allfam database. These families comprise the prolamin and cupin superfamilies, pathogenesis related proteins, profilins, thaumatin-like proteins, oleosins, expansins, a number of enzymes and protease inhibitors among others. The classification on structural and thus biochemical and functional similarities will provide a new outlook on the molecules and might contribute to answer the question about allergenicity of different proteins. This will help to define clinical relevant allergenic molecules and explain cross-reactive phenomena between single food allergen sources as well as between food allergens and allergenic molecules of other origins (e.g. pollen).