Abstract: Food allergy is an important public health issue in industrial countries due to the increasing prevalence and the potential life-threatening consequence. The understanding of food allergy mechanisms usually comes from experimental mouse models, which are broadly divided into two categories: oral sensitization model and topical or epicutaneous sensitization model. However, few studies have been focused on the difference between the two categories and the selection of the appropriate one. In this study, we aimed to develop a suitable route for tropomyosin administration by comparing the allergenicity of oral gavage and intraperitoneal injection in BALB/c mice in order to establish an effective animal model and to investigate the underlying mechanisms at the molecular and immunological levels, which will provide a theoretical basis for the establishment of animal model for food allergen research, the exploration of the mechanism of food allergen sensitization, and the prevention and treatment of food allergy. Results indicated that higher tropomyosin-specific immunoglobulin (Ig) E, histamine, and helper T cell (Th) type 2 cytokines were observed in intraperitoneally sensitized mice than those intragastrically sensitized, indicating that intraperitoneal injection was more sensitive in inducing systemic food allergy. Furthermore, higher levels of serum tropomyosin-specific IgG2a and interferon gamma, as well as regulatory T cell population were observed in intragastrically sensitized mice, suggesting that oral gavage may still develop oral tolerance to decrease the allergenicity of shrimp tropomyosin in BALB/c mice in spite of the presence of mucosal adjuvant. This experiment showed that intraperitoneal injection of tropomyosin to sensitized mice is easier than oral gavage, breaking the Th1/Th2 balance and making Th2 response dominant. Accordingly, intraperitoneal injection is more suitable to establish an animal model for food allergy research.

Key words: tropomyosin, oral gavage, intraperitoneal injection, food allergy, mouse model