An animal model for shrimp allergy: The influence of genetic background and adjuvant on the allergen-specific IgE response

Abstract

Rationale Shrimp allergy is characterized by severe symptoms, yet no specific immunotherapy (SIT) is available due to expected severe adverse reactions. Our aim was to develop a mouse model of shrimp allergy that mimics the immune response of human shrimp-allergic individuals. Methods Mice of the strains Balb/c, C3H/HeJ, C57Bl/6J, and CBA/J were sensitized with extract of brown shrimp (Penaeus aztecus) using cholera toxin (oral), alum (i.p.), and B. pertussis (i.p.) as adjuvants. The IgE responses were determined by sensitizing rat basophilic leukemia (RBL-2H3) with mouse sera and measuring the beta-hexosaminidase release upon allergen challenge with shrimp extract and recombinant Pen a 1, the major shrimp allergen. Results Of the four mouse strain tested the strongest IgE response was observed in C3H/HeJ and CBA/J mice, with some activity in sera from sensitized Balb/c mice; C57Bl/6J mice did not produce appreciable amounts of specific IgE antibodies with any of the adjuvants used. Alum and cholera toxin were the most effective adjuvants to induce IgE antibodies to shrimp extract, however, only C3H/HeJ and CBA/J mice that received cholera toxin as adjuvant produced IgE antibodies to Pen a 1 as measured by mediator release assay. Conclusions Sensitizing C3H/HeJ orally with shrimp extract using cholera toxin as adjuvant produces an immune response that is characterized by high amounts of specific IgE to shrimp. In comparison with CBA/J mice, only C3H/HeJ produced Pen a 1-specific IgE with both cholera toxin and alum as adjuvants, and, thus, C3H/HeJ mice plus cholera toxin may be to better model to study shrimp allergy.