RNAi suppression of rice endogenous storage proteins enhances the production of rice-based Botulinum neutrotoxin type A vaccine

Yoshikazu Yuki, Mio Mejima, Shiho Kurokawa, Tomoko Hiroiwa, Il Gyu Kong, Masaharu Kuroda, Yoko Takahashi, Tomonori Nochi, Daisuke Tokuhara, Tomoko Kohda, Shunji Kozaki, Hiroshi Kiyono

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


Mucosal vaccines based on rice (MucoRice) offer a highly practical and cost-effective strategy for vaccinating large populations against mucosal infections. However, the limitation of low expression and yield of vaccine antigens with high molecular weight remains to be overcome. Here, we introduced RNAi technology to advance the MucoRice system by co-introducing antisense sequences specific for genes encoding endogenous rice storage proteins to minimize storage protein production and allow more space for the accumulation of vaccine antigen in rice seed. When we used RNAi suppression of a combination of major rice endogenous storage proteins, 13. kDa prolamin and glutelin A in a T-DNA vector, we could highly express a vaccine comprising the 45. kDa C-terminal half of the heavy chain of botulinum type A neurotoxin (BoHc), at an average of 100. μg per seed (MucoRice-BoHc). The MucoRice-Hc was water soluble, and was expressed in the cytoplasm but not in protein body I or II of rice seeds. Thus, our adaptation of the RNAi system improved the yield of a vaccine antigen with a high molecular weight. When the mucosal immunogenicity of the purified MucoRice-BoHc was examined, the vaccine induced protective immunity against a challenge with botulinum type A neurotoxin in mice. These findings demonstrate the efficiency and utility of the advanced MucoRice system as an innovative vaccine production system for generating highly immunogenic mucosal vaccines of high-molecular-weight antigens.

Original languageEnglish
Pages (from-to)4160-4166
Number of pages7
Issue number28
Publication statusPublished - 2012 Jun 13
Externally publishedYes


  • Botulinum neutrotoxin
  • MucoRice
  • Nasal vaccine
  • RNAi
  • Rice

ASJC Scopus subject areas

  • Molecular Medicine
  • Immunology and Microbiology(all)
  • veterinary(all)
  • Public Health, Environmental and Occupational Health
  • Infectious Diseases


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