Resistance of the cholera vaccine candidate IEM108 against CTXPhi infection.

Abstract

The cholera toxin (CT) genes ctxAB are carried on a lysogenic phage of Vibrio cholerae, CTXPhi, which can transfer ctxAB between toxigenic and nontoxigenic strains of bacteria. This transfer may pose a problem when live oral cholera vaccine is given to people in epidemic areas, because the toxin genes can be reacquired by the vaccine strains. To address this problem, we have constructed a live vaccine candidate, IEM108, which carries an El Tor-derived rstR gene. This gene encodes a repressor and can render bacterial resistance to CTXPhi infection. In this study, we evaluated the resistance of IEM108 against CTXPhi infection by using a CTXPhi marked for chloramphenicol (CAF) resistance and an in vivo model. We found that the cloned rstR gene rendered IEM108 immune to infection with the marked CTXPhi. In addition, the infection rate of IEM108 was even lower than that of the native CTXPhi-positive strain. These results suggest that the vaccine candidate IEM108 is resistant to infection by CTXPhi.

• Authors: Guangwen Liu, Meiying Yan, Weili Liang, Guoming Qi, Yanqing Liu, Shouyi Gao, Biao Kan
• Journal: Vaccine (Vaccine) Vol. 24 Issue 11 Pg. 1749-55 (Mar 10 2006) ISSN: 0264-410X [Print] Netherlands
• PMID: 16343705 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Bacterial Proteins
• Cholera Vaccines
• DNA, Bacterial
• Repressor Proteins
• RstR protein, Vibrio cholerae
• Cholera Toxin

Topics

• Animals
• Bacterial Proteins (genetics)
• Blotting, Southern
• Chloramphenicol Resistance (genetics)
• Cholera Toxin (genetics)
• Cholera Vaccines (genetics)
• DNA, Bacterial (analysis)
• Genes, Reporter
• Humans
• Inovirus (genetics, physiology)
• Intestine, Small (microbiology)
• Rabbits
• Repressor Proteins (genetics)
• Transduction, Genetic
• Vibrio cholerae (genetics, growth & development, virology)