Efficacy of oral immunotherapy with a rice-based edible vaccine containing hypoallergenic Japanese cedar pollen allergens for treatment of established allergic conjunctivitis in mice
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Background: We have previously shown that prophylactic oral administration of transgenic rice seeds expressing hypoallergenic modified antigens suppressed the development of allergic conjunctivitis induced by Japanese cedar pollen. We have now investigated the efficacy of oral immunotherapy with such transgenic rice for established allergic conjunctivitis in mice.
Methods: BALB/c mice were sensitized with two intraperitoneal injections of Japanese cedar pollen in alum, challenged with pollen in eyedrops, and then fed for 16 days with transgenic rice seeds expressing modified Japanese cedar pollen allergens Cry j 1 and Cry j 2 or with nontransgenic rice seeds as a control. They were then challenged twice with pollen in eyedrops, with clinical signs being evaluated at 15 min after the first challenge and the eyes, blood, spleen, and lymph nodes being isolated at 24 h after the second challenge.
Results: The number of eosinophils in the conjunctiva and the clinical score for conjunctivitis were both significantly lower in mice fed the transgenic rice than in those fed nontransgenic rice. Oral vaccination with transgenic rice seeds also resulted in a significant increase in the production of IFN-g by splenocytes, whereas it had no effect on the number of CD4þCD25þFoxp3þ regulatory T cells in the spleen or submandibular or mesenteric lymph nodes.
Conclusions: Oral administration of transgenic rice seeds expressing hypoallergenic allergens ameliorated allergic conjunctivitis in the established setting. Such a rice-based edible vaccine is potentially both safe and effective for oral immunotherapy in individuals with allergic conjunctivitis.
This study was supported by funding from the charitable Trust Fund for Ophthalmic Research in Commemoration of Santen Pharmaceutical's Founder to K.F. as well as by “Agri-Health Translational Research Projects” of the Ministry of Agriculture, Forestry, and Fisheries of Japan to F.T. The funding sources played no role in study design; in collection, analysis, or interpretation of data; or in writing the report.
Japanese Society of Allergology
Copyright © 2017, Japanese Society of Allergology. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).