Oral Immunotherapy for Allergic Conjunctivitis

Antigen-specific immunotherapy is expected to be a desirable treatment for allergic diseases. Currently, antigen-specific immunotherapy is performed by administering disease-causing antigens subcutaneously or sublingually. These approaches induce long-term remission in patients with allergic rhinitis or asthma. The oral route is an alternative to subcutaneous and sublingual routes, and can also induce long-term remission, a phenomenon known as oral tolerance. The effectiveness of oral tolerance has been reported in the context of autoimmune diseases, food allergies, asthma, atopic dermatitis, and allergic rhinitis in both human patients and animal models. However, few studies have examined its efficacy in animal models of allergic conjunctivitis. Previously, we showed that ovalbumin feeding suppressed ovalbumin-induced experimental allergic conjunctivitis, indicating the induction of oral tolerance is effective in treating experimental allergic conjunctivitis. In recent years, transgenic rice has been developed that can induce oral tolerance and reduce the severity of anaphylaxis. The major Japanese cedar pollen antigens in transgenic rice, Cryptomeria japonica 1 and C. japonica 2, were deconstructed by molecular shuffling, fragmentation, and changes in the oligomeric structure. Thus, transgenic rice may be an effective treatment for allergic conjunctivitis.