A recombinant live oral cholera vaccine

Abstract

A pathogenic strain of Vibrio cholerae was attenuated by deletion of DNA sequences encoding the A1 subunit of the cholera enterotoxin. A restriction endonuclease fragment encoding the A1, but not the A2 or B sequences was deleted in vitro from cloned cholera toxin genes. The mutation was then recombined into the chromosome of V.cholerae Ogawa 395, a pathogenic strain that confers complete immunity to subsequent infection following an initial clinical infection. The resulting strain, which produces the immunogenic but nontoxic B subunit of cholera toxin and is unaltered in other critical antigens, represents a promising candidate for an attenuated live oral cholera vaccine. © 1984, Nature Publishing Group. All rights reserved.