Immunoproteomic identification of allergenic proteins in pecan (Carya illinoinensis) pollen

Pecan (C. illinoinensis) pollen is an important cause of allergic respiratory disease. Pecan is distributed worldwide as shade, ornamental or cultivation tree. To date three well known pecan food allergens have been reported, however, pollen allergens have not been identified. Here, we describe the first identification of IgE recognized pecan pollen proteins, for which proteins were analyzed by 2-DE and immunoblotting using a pool of 8 sera from pecan sensitive patients as primary antibody. IgE recognized protein spots were analyzed by LC-MS/MS and identified using a database of translated protein sequences obtained by the assembly of C. illinoinensis public transcriptomic information. This study has identified 17 IgE binding proteins from pecan pollen including proteins widely recognized as allergens and panallergens. These findings will contribute to develop specific diagnosis and treatment of pecan pollen allergy. Significance: Pecan is a tree highly valued for its fruits that have a great commercial value. To date three pecan seed storage proteins have been officially recognized by the WHO/IUIS allergen nomenclature subcommittee as food allergens (Car i 1, Car i 2 and Car i 4). Pecan tree pollen is highly allergenic and a clinically relevant cause of allergies in North America (USA and Mexico) and regions where the tree is extensively cultivated (Israel, South Africa, Australia, Egypt, Peru, Argentina, and Brazil). Here, we describe the first identification of IgE recognized pollen proteins using an immunoproteomics approach and a protein database created by the assembly of pecan public transcriptomic information. The findings described here will allow the development of new diagnostic and therapeutic modalities for pecan pollen allergy.