Construction of Candidate <i>Yersinia pestis</i> Vaccine Strains with Reduced Reactogenicity

Abstract

The technology of directed constructing of non-reverting Y. pestis ∆lpxM mutants, lacking antibiotic resistance markers was developed. It included direct site-specific mutagenesis, cloning of mutant ∆lpxM::cat allele in pCVD442 suicide vector, homologous recombination in vivo and deletion of the antibiotic resistance cassette. lpxM gene knockout mutant created on the basis of vaccine Y. pestis EV NIIEG strain lacking antibiotic resistance markers synthesized a lipopolysaccharide (LPS) with reduced ability to stimulate TNF-α production. The level of reduction of anti-inflammatory activity of the LPS synthesized by the mutant Y. pestis EV∆ lpxM strain was significantly higher in the test with human target cells in comparison with mouse model.

Keywords

• <i>lpxm</i>
• site-specific mutagenesis
• lipopolysaccharide
• endotoxic activity
• <i>yersinia pestis</i>