Improved Animal Model for Assessment of Allergenic Potential of Foods Through Selective Deletion of T Cells and Global Gene Expression AnalysisEPA Grant Number: R833134
Title: Improved Animal Model for Assessment of Allergenic Potential of Foods Through Selective Deletion of T Cells and Global Gene Expression Analysis
Investigators: HogenEsch, Harm , Muir, William
Institution: Purdue University
EPA Project Officer: McOliver, Cynthia
Project Period: November 1, 2006 through October 31, 2009 (Extended to November 30, 2010)
Project Amount: $398,497
RFA: Biotechnology: Potential Allergenicity of Genetically Engineered Foods (2006) RFA Text | Recipients Lists
Research Category: Food Allergy , Health
The goal of the research is to develop an improved animal model to test for food allergies and to identify changes in gene expression that can serve as early biomarkers for the detection of food allergy.
Genetic modification of plants for human consumption is increasingly used for the purpose of increased yield and disease resistance as well as the creation of specialty food products. While GM foods are not inherently less safe than conventional foods, the insertion of genes from a wide variety of sources creates the potential for new food allergens. The overall objective of the study is to develop a new animal model to test for allergenic potential of foods that requires a short duration of testing; has increased sensitivity and discriminatory power over existing models; and is relatively easy to use. The specific objectives of this proposal are:
- to determine if mice that lack a subpopulation of T lymphocytes known as TCRγδ+ T cells, are more sensitive to food allergens than mice with an intact TCRγδ+ T cell population. Previous studies indicate that TCRγδ+ T cells are important for the maintenance of oral tolerance suggesting that their absence will make the mice more sensitive to food allergens;
- to determine if oral administration of food proteins to TCRγδ-deficient mice can discriminate between allergenic and non-allergenic proteins;
- to identify early biomarkers of food allergenicity in mice that shorten the exposure protocol and increase the sensitivity of the mouse model.
Genetically TCRγδ-deficient mice on a C57BL/6 background and BALB/c mice treated with anti-TCRγδ-antibodies will be used to address objectives 1 and 2. The mice will be administered proteins orally without adjuvants and the IgE and IgG antibody response will be measured. The proteins will be two preparations of known high allergenicity, i.e. ovalbumin and peanut protein extract, and two preparations of low allergenicity, potato protein extract and ribulose. To address objective 3, mice will be exposed by intragastric gavage to the high allergenic and low allergenic proteins, and mRNA from spleen, mesenteric lymph node and intestine will be collected for gene expression profiling using microarrays. Comparison of gene expression between highly allergenic protein-treated and low allergenic protein-treated mice should identify changes in gene expression that are specific for responses to food allergens. These changes will be verified and validated for a subset of genes by quantitative RT-PCR. This research should identify biomarkers that can detect the response of mice to food allergens in a short term exposure model.
The result of this research will be an animal model that is suitable for testing of the allergenic potential of genetically engineered foods along with biomarkers for early detection of food allergies. The proposed mouse model uses oral exposure without adjuvants and requires a relatively easy, short exposure protocol as a result of the availability of sensitive biomarkers for rapid detection of gene-expression changes in the exposed mice.