Turning self-destructing Salmonella into a universal DNA vaccine delivery platform

Wei Kong, Matthew Brovold, Brian A. Koeneman, Josephine Clark-Curtiss, Roy Curtiss

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


We previously developed a biological containment system using recombinant Salmonella Typhimurium strains that are attenuated yet capable of synthesizing protective antigens. The regulated delayed attenuation and programmed self-destructing features designed into these S. Typhimurium strains enable them to efficiently colonize host tissues and allow release of the bacterial cell contents after lysis. To turn such a recombinant attenuated Salmonella vaccine (RASV) strain into a universal DNA vaccine-delivery vehicle, our approach was to genetically modify RASV strains to display a hyperinvasive phenotype to maximize Salmonella host entry and host cell internalization, to enable Salmonella endosomal escape to release a DNA vaccine into the cytosol, and to decrease Salmonella-induced pyroptosis/apoptosis that allows the DNA vaccine time to traffic to the nucleus for efficient synthesis of encoded protective antigens. A DNA vaccine vector that encodes a domain that contributes to the arabinose-regulated lysis phenotype but has a eukaryotic promoter was constructed. The vector was then improved by insertion of multiple DNA nuclear-targeting sequences for efficient nuclear trafficking and gene expression, and by increasing nuclease resistance to protect the plasmid from host degradation. A DNA vaccine encoding influenza WSN virus HA antigen delivered by the RASV strain with the best genetic attributes induced complete protection to mice against a lethal influenza virus challenge. Adoption of these technological improvements will revolutionize means for effective delivery of DNA vaccines to stimulate mucosal, systemic, and cellular protective immunities, and lead to a paradigm shift in cost-effective control and prevention of a diversity of diseases.

Original languageEnglish (US)
Pages (from-to)19414-19419
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number47
StatePublished - Nov 20 2012


  • Needle-free
  • Vaccinology

ASJC Scopus subject areas

  • General


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