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Assessing the allergenic potential of food proteins in germ-free and conventional mice
No animal model of food allergy has proven to be predictive of human responses in ranking purified dietary proteins in prevalence or potency of allergy. Since the gastrointestinal microbiota is thought to influence the induction of oral tolerance, we hypothesized that a germ-free mouse model would more accurately predict human allergic responses than conventional mice. The overall goal of this work was to develop a model system to predict the potential allergenicity of novel proteins. ^ Initial studies aimed to identify the route of sensitization and microbial status that results in the most reproducible responses in mice. Conventional and germ-free C3H/HeN mice were sensitized with the major milk allergen, β-lactoglobulin (BLG), using intraperitoneal (IP) or intragastric (IG) sensitization. One week following the final sensitization, a 500 &mgr;g IP or 60 mg BLG IG challenge was administered. Using various markers indicative of food allergy, the route of sensitization, route of challenge, and microbial status were evaluated. IP sensitization and challenge was determined to be the optimal route as more mice had clinical symptoms and allergen-specific IgE than when the IG route was utilized. Mice with a natural microbiota had greater variability in allergic responses, and a tendency toward less severe allergic symptoms compared to germ-free mice. Lipopolysaccharide contamination was found to impact the sensitization potential of purified protein in germ-free more so than in conventional mice. ^ The IP protocol was used to test the model's ability to predict allergenicity using three proteins of varying human allergenicity. Purified potent dietary peanut allergen, Ara h 2; moderately potent bovine milk allergen, β-lactoglobulin; and non- or weakly allergenic protein, soy lipoxygenase were characterized and used to sensitize and challenge the germ-free mice. ^ The results indicate this animal model was able to reliably differentiate proteins based on inherent allergenicity as strong responses to potent allergens, and weak responses to a non-allergen were observed.^
Biology, Molecular|Biology, Microbiology|Health Sciences, Immunology
Marsteller, Nathan L, "Assessing the allergenic potential of food proteins in germ-free and conventional mice" (2014). ETD collection for University of Nebraska - Lincoln. AAI3665957.