Abstract
The genes encoding the A (toxic) subunit of cholera toxin were deleted from pathogenic Vibrio cholerae O1 strain 569B by recombinant techniques, leaving intact production of immunogenic, non-toxic B subunit. The resultant strain, CVD 103, evaluated for safety, immunogenicity, and efficacy as a live oral vaccine, was highly attenuated and elicited strong antibacterial and antitoxic immune responses; a single dose significantly protected volunteers against challenge with pathogenic V cholerae O1 of either serotype or biotype. A further derivative, CVD 103-HgR, which has an Hg++-resistance gene to differentiate it from wild-type vibrios, was also well-tolerated, immunogenic, and protective; moreover, faecal excretion of this derivative was significantly lower than that of CVD 103, which should minimise environmental spread of the vaccine. CVD 103-HgR is a candidate for expanded clinical trials in endemic areas.
Publication types
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Clinical Trial
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Administration, Oral
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Adult
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Cholera / prevention & control*
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Cholera Vaccines* / administration & dosage
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Cholera Vaccines* / adverse effects
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Cholera Vaccines* / classification
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Cholera Vaccines* / immunology
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Clinical Trials as Topic
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Double-Blind Method
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Drug Evaluation
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Humans
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Immunoglobulin G / analysis
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Time Factors
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Vaccination* / adverse effects
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Vaccines, Attenuated* / administration & dosage
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Vaccines, Attenuated* / adverse effects
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Vaccines, Attenuated* / classification
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Vaccines, Attenuated* / immunology
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Vaccines, Synthetic / administration & dosage
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Vaccines, Synthetic / adverse effects
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Vaccines, Synthetic / classification
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Vaccines, Synthetic / immunology
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Vibrio cholerae / classification
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Vibrio cholerae / genetics
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Vibrio cholerae / immunology
Substances
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Cholera Vaccines
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Immunoglobulin G
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Vaccines, Attenuated
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Vaccines, Synthetic