title: New technologies in developing recombinant attenuated Salmonella vaccine vectors.
abstract: Recombinant attenuated Salmonella vaccine (RASV) vectors producing recombinant gene-encoded protective antigens should have special traits. These features ensure that the vaccines survive stresses encountered in the gastrointestinal tract following oral vaccination to colonize lymphoid tissues without causing disease symptoms and to result in induction of long-lasting protective immune responses. We recently described ways to achieve these goals by using regulated delayed in vivo attenuation and regulated delayed in vivo antigen synthesis, enabling RASVs to efficiently colonize effector lymphoid tissues and to serve as factories to synthesize protective antigens that induce higher protective immune responses. We also developed some additional new strategies to increase vaccine safety and efficiency. Modification of lipid A can reduce the inflammatory responses without compromising the vaccine efficiency. Outer membrane vesicles (OMVs) from Salmonella-containing heterologous protective antigens can be used to increase vaccine efficiency. A dual-plasmid system, possessing Asd+ and DadB+ selection markers, each specifying a different protective antigen, can be used to develop multivalent live vaccines. These new technologies have been adopted to develop a novel, low-cost RASV synthesizing multiple protective pneumococcal protein antigens that could be safe for newborns/infants and induce protective immunity to diverse Streptococcus pneumoniae serotypes after oral immunization.
authors.affiliation: Center for Infectious Diseases and Vaccinology, The Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, AZ 85287-5401, USA.
authors.forename: Shifeng
authors.initials: S
authors.lastname: Wang
authors.forename: Qingke
authors.initials: Q
authors.lastname: Kong
authors.forename: Roy
authors.initials: R
authors.lastname: Curtiss
mesh_terms: D000942:Antigens, Bacterial / Q000096:biosynthesis* / Q000235:genetics; D004337:Drug Carriers; D055808:Drug Discovery / Q000639:trends; D015964:Gene Expression Regulation, Bacterial; D005822:Genetic Vectors; D006801:Humans; D008050:Lipid A / Q000235:genetics / Q000633:toxicity; D022242:Pneumococcal Vaccines / Q000235:genetics / Q000276:immunology; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D012475:Salmonella / Q000235:genetics / Q000472:pathogenicity*; D022142:Secretory Vesicles / Q000276:immunology / Q000378:metabolism; D013296:Streptococcus pneumoniae / Q000235:genetics / Q000276:immunology; D014613:Vaccines, Attenuated / Q000235:genetics / Q000276:immunology; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D004337:Drug Carriers; D008050:Lipid A; D022242:Pneumococcal Vaccines; D011994:Recombinant Proteins; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic