Modificaciones genéticas en mutantes atoxigénicos de Vibrio cholerae O139 que mejoran sus propiedades como candidatos vacunales.

The hemagglutinin/protease represents an attractive locus for the insertion of heterologous tags which unequivocally distinguish vaccine candidates from wild type of Vibrio cholerae. An atoxigenic mutant of Vibrio cholerae O139 was sequentially manipulated using molecular biology methods to obtain hapA::celA derivatives which were later improved in their environmental safety by means of an mshA mutation. The celA gene from Clostridium thermocellum was used to tag the vaccine prototypes. The marked strains could be unequivocally distinguished using a simple microbiological technique. The mshA gene codes the main subunit of pilus MSHA that constitutes the portal of entry of several vibriophages, such as VGJφ which is able to carry the cholera toxin genes between different Vibrio cholerae strains by an efficient mechanism of specialized transduction. The mutants thus obtained resulted motiles and showed a good colonization capacity in the infant mouse cholera model, traits which are remarkable to vaccine candidates. [ABSTRACT FROM AUTHOR]