Molecular features of maize allergens and their implications in human health

Foods from plant origin, particularly nuts and seeds, represent the major source of registered food allergy due to the high variability of plant allergenic molecules, which depends on plant growing conditions, seed/fruit ripening, environmental stresses and/or industrial processing. Maize, one of the major human diet components, is one of the most world widely consumed cereals. It has become therefore one of the major causes of food allergy due to the widespread corn derived food products, which make difficult itsto avoid it. However, detailled biochemical knowledge of maize allergy is lacking. There are several unanswered questions including the symptoms and mechanisms involved in maize allergenic reactions, its prevalence in adults and children, the implicated allergen molecules and the clinical cross-sensitization. Therefore, diagnostic tests and maize allergy management constitute a field of great interest. Currently, maize allergen proteins are classified into 20 different families, displaying diverse structures and functions. They are responsible for many IgE cross-reactions between unrelated pollen and plant food allergen sources. The most relevant maize allergen molecules belong to the expansin and the Ole e 1 superfamilies, the panallergen profilin, and the Lipid Transfer Proteins (LTPs), i.e. Zea m 14, the major maize allergen. Agricultural biotechnology promises plant food production through genetically modified (GM) crops with improved agronomic characteristics and enhanced consumer benefits. Numerous efforts in plant breeding programs have resulted in producing low-allergen or allergen-null plants that could moderate the allergic response. For this purpose, identification of new genes, and knowledge of allergen protein structures and function is crucial for the understanding of biochemical processes inducing maize allergy. Computational biology and protein modeling are increasingly used to evaluate whether a novel protein correspons to a known allergen, has a potential to become an allergen or could possibly cross-react with another existing allergen. In order to answer the above crucial questions and bring insights into the processes of food allergy, we focus our attention in this review on maize allergens protein families, their biochemical, structural and immunological properties, while discussing possible strategies to predict biological consequences of allergen sensitization and cross-reactivity as well as therapies to mitigate maize allergy.