Assessment of the allergenic potential of proteins.
The development of novel foods, including foods derived from genetically modified plants, has generated considerable interest in the design and application of appropriate safety assurance measures. A specific focus of attention has been on allergenicity, and in particular the need to determine whether the products of novel genes introduced into food plants have the potential to cause allergic sensitisation. Among the approaches applied currently are considerations of whether a new protein has structural, sequence and/or antigenic similarities with known food allergens, and whether or not it displays resistance to digestion within a simulated gastric fluid, or by pepsin. Although such data are useful in an overall hazard assessment, they are neither individually, nor collectively, able to provide a direct evaluation of inherent sensitising potential. For this reason there is a need to develop and apply appropriate animal models that will offer a more holistic view of sensitising activity. Several methods have been suggested, but as yet none has been evaluated fully or validated. Nevertheless, significant progress has been made and in this article an experimental approach using BALB/c strain mice in which animals are exposed to the test protein via systemic (intraperitoneal, or in certain circumstances, intradermal) administration is described. Inherent sensitising potential is measured as a function of induced IgE antibody responses. Experience to date is encouraging and the data available reveal that this method is able to distinguish between proteins of different allergenic potential.