Nochi Tomonori, Takagi Hidenori, Yuki Yoshikazu, Yang Lijun, Masumura Takehiro, Mejima Mio, Nakanishi Ushio, Matsumura Akiko, Uozumi Akihiro, Hiroi Takachika, Morita Shigeto, Tanaka Kunisuke, Takaiwa Fumio, Kiyono Hiroshi
*Division of Mucosal Immunology, Department of Microbiology and Immunology, The Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan.
Proc Natl Acad Sci U S A. 2007 Jun 26;104(26):10986-91. doi: 10.1073/pnas.0703766104. Epub 2007 Jun 15.
Capable of inducing antigen-specific immune responses in both systemic and mucosal compartments without the use of syringe and needle, mucosal vaccination is considered ideal for the global control of infectious diseases. In this study, we developed a rice-based oral vaccine expressing cholera toxin B subunit (CTB) under the control of the endosperm-specific expression promoter 2.3-kb glutelin GluB-1 with codon usage optimization for expression in rice seed. An average of 30 mug of CTB per seed was stored in the protein bodies, which are storage organelles in rice. When mucosally fed, rice seeds expressing CTB were taken up by the M cells covering the Peyer's patches and induced CTB-specific serum IgG and mucosal IgA antibodies with neutralizing activity. When expressed in rice, CTB was protected from pepsin digestion in vitro. Rice-expressed CTB also remained stable and thus maintained immunogenicity at room temperature for >1.5 years, meaning that antigen-specific mucosal immune responses were induced at much lower doses than were necessary with purified recombinant CTB. Because they require neither refrigeration (cold-chain management) nor a needle, these rice-based mucosal vaccines offer a highly practical and cost-effective strategy for orally vaccinating large populations against mucosal infections, including those that may result from an act of bioterrorism.
黏膜疫苗能够在不使用注射器和针头的情况下，在全身和黏膜部位诱导抗原特异性免疫反应，被认为是全球控制传染病的理想选择。在本研究中，我们开发了一种基于水稻的口服疫苗，该疫苗在胚乳特异性表达启动子2.3 kb谷蛋白GluB-1的控制下表达霍乱毒素B亚基（CTB），并对密码子使用进行了优化以在水稻种子中表达。每个种子平均有30微克的CTB储存在蛋白体中，蛋白体是水稻中的储存细胞器。当经黏膜喂食时，表达CTB的水稻种子被覆盖派尔集合淋巴结的M细胞摄取，并诱导产生具有中和活性的CTB特异性血清IgG和黏膜IgA抗体。当在水稻中表达时，CTB在体外可免受胃蛋白酶消化。水稻表达的CTB也保持稳定，因此在室温下>1.5年仍保持免疫原性，这意味着诱导抗原特异性黏膜免疫反应所需的剂量比纯化的重组CTB低得多。由于这些基于水稻的黏膜疫苗既不需要冷藏（冷链管理）也不需要针头，它们为大规模人群口服接种预防黏膜感染（包括可能由生物恐怖主义行为导致的感染）提供了一种高度实用且具有成本效益的策略。
