title: Oral immunogenicity and protective efficacy in mice of transgenic rice plants producing a vaccine candidate antigen (As16) of Ascaris suum fused with cholera toxin B subunit.
abstract: Cereal crops such as maize and rice are considered attractive for vaccine production and oral delivery. Here, we evaluated the rice Oryza sativa for production of As16-an antigen protective against the roundworm Ascaris suum. The antigen was produced as a chimeric protein fused with cholera toxin B subunit (CTB), and its expression level in the endosperm reached 50 microg/g seed. Feeding the transgenic (Tg) rice seeds to mice elicited an As16-specific serum antibody response when administered in combination with cholera toxin (CT) as the mucosal adjuvant. Although omitting the adjuvant from the vaccine formulation resulted in failure to develop the specific immune response, subcutaneous booster immunization with bacterially expressed As16 induced the antibody response, indicating priming capability of the Tg rice. Tg rice/CT-fed mice orally administered A. suum eggs had a lower lung worm burden than control mice. This suggests that the rice-delivered antigen functions as a prophylactic edible vaccine for controlling parasitic infection in animals.
authors.affiliation: Laboratory of Global Animal Resource Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan. aymatsu@mail.ecc.u-tokyo.ac.jp
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Seiko
authors.initials: S
authors.lastname: Suzuki
authors.forename: Tomoko
authors.initials: T
authors.lastname: Nozoye
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamakawa
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takashima
authors.forename: Takeshi
authors.initials: T
authors.lastname: Arakawa
authors.forename: Naotoshi
authors.initials: N
authors.lastname: Tsuji
authors.forename: Fumio
authors.initials: F
authors.lastname: Takaiwa
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Hayashi