Development of transgenic rice expressing mite antigen for a new concept of immunotherapy.

Background: To elucidate the usefulness of antigen-specific immunotherapy based on oral vaccination with an edible part of the plant, we examined the effect of transgenic (Tg) rice seeds expressing an immunodominant fragment of the group 1 antigen of Dermatophagoides pteronyssinus (Der p 1) on a murine model of asthma.

Methods: Mice were orally vaccinated with the Tg or non-Tg rice seeds for 2 weeks, then they were immunized with recombinant Der p 1 (rDer p 1) and alum intraperitoneally. Antigen-induced immune responses, such as proliferation and cytokine production of CD4+ T cells, antigen-specific serum IgE and IgG, and infiltration of inflammatory cells into the airways were investigated in those mice.

Results: The proliferation and Th2 cytokine production of CD4+ T cells in vitro, antigen-specific IgE and IgG synthesis as well as accumulation of eosinophils and lymphocytes into the airways in vivo were significantly inhibited by administration of the Tg rice.

Conclusions: These results suggest that the edible vaccines using Tg rice seeds are useful for the treatment of allergic disorders including bronchial asthma.