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Oral rice‐based non‐toxic mutant cholera toxin induces enterotoxin neutralizing immunity
Author(s) -
YUKI Yoshikazu,
TOKUHARA Daisuke,
NOCHI Tomonori,
YASUDA Hiroshi,
MEJIMA Mio,
KUROKAWA Shiho,
TAKAIWA Fumio,
KIYONO Hiroshi
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.853.6
Subject(s) - cholera toxin , enterotoxin , western blot , microbiology and biotechnology , antibody , mutant , immunity , heat labile enterotoxin , glutelin , chemistry , toxin , biology , immune system , biochemistry , immunology , gene , storage protein , escherichia coli
Oral administration of rice‐expressed cholera toxin B subunit (CTB) has been shown to induce enterotoxin neutralizing immunity. We examined here whether oral vaccination of transgenic rice seed expressing nontoxic double mutant cholera toxin (dmCT), which consisted of two amino acid substitutions of ADP‐ribosyltransferase active center (E112K) and carboxyl terminal KDEL (E112K/KDGL) in A subunit (CTA) would effectively induce enterotoxin‐neutralizing immunity. The CTA and CTB in dmCT were expressed in rice seed under the control of the endosperm‐specific expression promoter 1.4Kb glutelin GluB‐3 and 2.3Kb glutelin GluB‐1, respectively. Using densitometry analysis, we found that an average 3 microgram of dmCT was stored in a seed. Western blot analysis under nonreducing conditions revealed that CTB expression in rice formed a pentamer but it was not associated with A subunit. When mucosally fed, the rice‐expressed dmCT induced CTB specific serum IgG and mucosal IgA antibodies with neutralizing activity but not any CTA specific serum and mucosal antibodies. These findings showed that the rice‐expressed dmCT generated protective immunity against cholera toxin after oral vaccination.