Molecular cloning and expression in Escherichia coli K-12 of the O antigens of the Inaba and Ogawa serotypes of the Vibrio cholerae O1 lipopolysaccharides and their potential for vaccine development.

The gene clusters that determine the biosynthesis of both the Inaba and Ogawa serotypes of the O antigen of the lipopolysaccharide of Vibrio cholerae were cloned and expressed in Escherichia coli K-12. Restriction analysis of the clones demonstrated that about 15 kilobases were common to all clones and a further 5 kilobases were common to the Ogawa clones. The O antigens expressed by E. coli K-12 had the specificity of V. cholerae. Antibodies raised against E. coli K-12 that harbor one of these clones, pPM1001 (Inaba), were as highly protective in the infant mouse model system as were antibodies to V. cholerae itself. Introduction of such clones into suitable carrier strains could be expected to produce a good oral immunogen against cholera.