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Bulletin of the World Health Organization logoLink to Bulletin of the World Health Organization
. 1979;57(4):643–647.

Attenuation of virulence by P and V plasmids in Vibrio cholerae: strains suitable for oral immunization*

V B Sinha, Brahm S Srivastava
PMCID: PMC2395831  PMID: 316741

Abstract

In a virulent strain of Vibrio cholerae, KB9, P and V plasmids were introduced by bacterial conjugation. Characterization of PV isolates and systematic screening of them in animal models of cholera revealed that a large number of PV isolates were non-pathogenic, owing to the loss of ability to synthesize toxin. Results obtained with two such strains, designated as KB9:PV and CD24, are described. The strains with plasmids were stable during in vitro cultivation or during two successive passages in rabbit intestine. Protection conferred by PV strains was determined in mouse protection tests and in the rabbit ileal loop model. The plasmid strains were immunogenic. In view of the results, it is proposed that PV-bearing attenuated strains should be tried in oral immunization.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Cash R. A., Music S. I., Libonati J. P., Schwartz A. R., Hornick R. B. Live oral cholera vaccine: evaluation of the clinical effectiveness of two strains in humans. Infect Immun. 1974 Oct;10(4):762–764. doi: 10.1128/iai.10.4.762-764.1974. [DOI] [PMC free article] [PubMed] [Google Scholar]
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