Assessment of the Brown Norway rat as a suitable model for the investigation of food allergy

Abstract

We have investigated the potential of the inbred Brown Norway (BN) rat as a model for food allergy using two different antigens, ovalbumin (OA) and semi-skimmed milk (SSM). The use of milk-free diet prior to and during exposure to SSM was a key factor in the induction of sensitisation to milk proteins. Investigation of dose received and timing of administration identified a sensitisation regimen using 500 μg SSM injected i.p. together with 1 mg CGN (adjuvant) on days 0 and 7 as the optimum conditions for induction of reaginic antibody production. In this model milk proteins were less allergenic than OA as the amount of SSM required to induce sensitivity was 20-fold greater. Examination of antigen-specificity of the IgG and reaginic antibody responses to a range of proteins, present in SSM, showed that the BN rats were capable of recognising a similar profile of allergens as those recognised by milk sensitive humans. Lactoferrin which is present in low concentrations in milk proved as allergenic as the major proteins in milk, the caseins and β-lactoglobulin. These studies have identified conditions for induction of sensitisation to milk proteins, and have shown the antibody specificity of these response to be similar to that in man. This suggests that the BN rat could provide the basis of a model for the investigation of allergic reactions to food.