Assessment of the Route of Exposure to Ovalbumin and Cow’s Milk Proteins on the Induction of IgE Responses in BALB/c Mice

SIMPLE SUMMARY: The mouse model is very valuable to scientists, mainly because many reagents are commercially available for conducting research in this animal model. In the search for a standardized mouse model of food allergy, the route of administration of the proteins of interest is a determinant to successfully sensitizing the mice. Our aim was to evaluate the IgE allergen-specific response to food proteins after their administration by the intragastric or intraperitoneal routes in BALB/c mice. The results show that the intraperitoneal administration of the allergens ovalbumin or cow’s milk protein triggered more robust and consistent immunoglobulin E responses than the intragastric administration of the proteins, whether Sucralfate is used or not (an antacid that can promote sensitization in mice and an allergic response similar to the one triggered in human beings). It is concluded that the intraperitoneal administration of food proteins is better than the intragastric one to sensitize BALB/c mice, even after gastric-acid suppression. We have generated scientific evidence to pave the way in the search for a reproducible mouse model of immunoglobulin E-mediated food allergy to evaluate the safety of crops derived from modern biotechnology, such as genetic engineering, or the safety and effectiveness of new food allergy therapies. ABSTRACT: BALB/c mice can be orally sensitized to food proteins under acid suppressive medication, mimicking human exposure and triggering a human-like allergic immune response. However, the reproducibility of such an oral food allergy model remains questionable. Our aim was to evaluate the IgE responses triggered against ovalbumin (OVA) and cow’s milk proteins (CMP) after intragastric (IG), either under gastric-acid suppression or not, or intraperitoneal (IP) sensitization in BALB/c mice. OVA (0.2 mg) and different concentrations of CMP were administered with/without the antacid sucralfate by the IG route. For IP sensitization, OVA or CMP (0.5 mg) were administered. ELISA was used to evaluate IgE responses. The IP sensitization protocols triggered more robust and consistent anti-OVA or anti-CMP IgE responses than the intragastric ones (with/without sucralfate) (p < 0.05). 2.7% (1/36), and 5.5% (3/54) of the mice that underwent the sucralfate-assisted IG protocol triggered IgE responses against OVA or CMP, respectively. All the mice were administered OVA or CMP via IP triggered detectable IgE responses. The IP sensitization model is more reliable than the IG one for evaluating the intrinsic sensitizing and/or allergenic potential of food proteins, even if IG immunizations are carried out under gastric-acid suppression.