Toxicology Letters 120 (2001) 171 – 180 Determination of protein allergenicity: studies in rats Andre ´ H. Penninks, Leon M.J. Knippels * Experimental Immunology, Diision of Toxicology, TNO Nutrition and Food Research, P.O. Box 360, 3700 AJ Zeist, The Netherlands Abstract For the safety evaluation of genetically engineered crops the potential allergenicity of the newly introduced protein(s) has become an important issue. There is, however, no universal and reliable test system for the evaluation of the allergenic potency of food products. The best known allergy assessment proposal is the careful stepwise process using the IFBC/ILSI decision tree. Unfortunately, the described tests are not always conclusive, especially if the gene source coding for the protein has no history of dietary use and/or an unknown history in terms of allergenicity. The further testing warranted should in particular be focused on the prediction of the sensitizing potential of the novel protein, for which animal models are considered to be needed. In this paper the results are summarized of a promising food allergy model developed in Brown Norway (BN) rats. The results demonstrate that BN rats can be sensitized orally to the various allergenic food proteins tested, resulting in significant antigen-specific IgE responses, without the use of adjuvants. Upon oral challenge of previously sensitized animals, local and systemic immune-mediated effects, such as increased gastrointestinal permeability and decreased breathing frequency and blood pressure, could also be observed. © 2001 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Protein allergenicity; Oral sensitization; GMOs; BN-rat model www.elsevier.com/locate/toxlet 1. Introduction Advances in modern biotechnology techniques will result in the introduction of an increasing number of new generations of food and food ingredients. In particular, the development and market introduction of genetically engineered food crops has gained considerable attention in the past few years. A large number of different plant species, including the most economically important crops like soy, corn, canola, cotton etc., have been successfully genetically engineered in the past few years, of which only a few have reached the marketplace. A toxicological evalua- tion and risk assessment are, in most cases, major items in the safety evaluation of novel foods and novel food ingredients. As some proteins in our food are responsible for the development of food allergy and most of the genetically modified foods developed up to know contain new proteins, their safety evalua- tion should include an assessment of the aller- genicity of such a new protein. Although, however, the potential allergenicity of foods * Corresponding author. Tel.: +31-30-6944564; fax: +31- 30-6960264. E-mail address: knippels@voeding.tno.nl (L.M.J. Knippels). 0378-4274/01/$ - see front matter © 2001 Elsevier Science Ireland Ltd. All rights reserved. PII:S0378-4274(01)00275-2