Oral administration of a T cell epitope inhibits symptoms and reactions of allergic rhinitis in Japanese cedar pollen allergen-sensitized mice.

Although the concept of a T cell epitope in specific immunoprophylaxis was proposed more than a decade ago, it had not been well demonstrated since then that a T cell epitope inhibits symptoms and reactions of allergic disease in animal models. In this study, we have established a system to evaluate symptoms and reactions of allergic rhinitis in mice, and investigated whether oral administration of a T cell epitope relieves sensitized mice of allergic rhinitis. P2-246-259 (RAEVSYVHVNGAKF) is a BALB/c mouse T-cell epitope of Cry j 2, which is a major Japanese cedar (Cryptomeria japonica) pollen allergen. Mice were administered orally with 200 microg/animal of P2-246-259 four times within 2 weeks before sensitization, and sensitized intranasally with Cry j 2 twice. Of the cardinal symptoms of allergic rhinitis, we assessed sneezing and airway obstruction, but could not estimate rhinorrhea or pruritus. Sneezing frequency was significantly increased by challenge with Cry j 2. Concerning allergic reactions, vascular permeability of the nasal mucosa in the early phase and hyperreactivity to histamine in the late phase were also exacerbated by the challenge. These symptoms and reactions of allergic rhinitis were significantly inhibited by oral administration of P2-246-259. These results indicate utility of mice as models for allergic rhinitis; furthermore, the effects of P2-246-259 on allergic rhinitis imply that oral administration of a T cell epitope is a promising approach for specific immunoprophylaxis.