title: Turning self-destructing Salmonella into a universal DNA vaccine delivery platform.
abstract: 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.
authors.affiliation: Center for Infectious Diseases and Vaccinology at the Biodesign Institute, and School of Life Sciences, Arizona State University, Tempe, AZ 85287-5401, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Kong
authors.forename: Matthew
authors.initials: M
authors.lastname: Brovold
authors.forename: Brian A
authors.initials: BA
authors.lastname: Koeneman
authors.forename: Josephine
authors.initials: J
authors.lastname: Clark-Curtiss
authors.forename: Roy
authors.initials: R
authors.lastname: Curtiss
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D000917:Antibody Formation / Q000276:immunology; D017209:Apoptosis; D001483:Base Sequence; D003851:Deoxyribonucleases / Q000378:metabolism; D018014:Gene Transfer Techniques; D005798:Genes, Bacterial / Q000235:genetics; D005818:Genetic Engineering; D005822:Genetic Vectors / Q000235:genetics; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000276:immunology; D007114:Immunization; D051379:Mice; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D012475:Salmonella / Q000235:genetics / Q000276:immunology*; D012481:Salmonella Infections, Animal / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control; D022562:Salmonella Vaccines / Q000276:immunology*; D014613:Vaccines, Attenuated / Q000276:immunology; D019444:Vaccines, DNA / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D022562:Salmonella Vaccines; D014613:Vaccines, Attenuated; D019444:Vaccines, DNA; D014614:Vaccines, Synthetic; D003851:Deoxyribonucleases