title: Developing live Shigella vaccines using lambda Red recombineering.
abstract: Live attenuated Shigella vaccines have shown promise in inducing protective immune responses in human clinical trials and as carriers of heterologous antigens from other mucosal pathogens. In the past, construction of Shigella vaccine strains relied on classical allelic exchange systems to genetically engineer the bacterial genome. These systems require extensive in vitro engineering of long homologous sequences to create recombinant replication-defective plasmids or phage. Alternatively, the lambda red recombination system from bacteriophage facilitates recombination with as little as 40 bp of homologous DNA. The process, referred to as recombineering, typically uses an inducible lambda red operon on a temperature-sensitive plasmid and optimal transformation conditions to integrate linear antibiotic resistance cassettes flanked by homologous sequences into a bacterial genome. Recent advances in recombineering have enabled modification of genomic DNA from bacterial pathogens including Salmonella, Yersinia, enteropathogenic Escherichia coli, or enterohemorrhagic E. coli and Shigella. These advances in recombineering have been used to systematically delete virulence-associated genes from Shigella, creating a number of isogenic strains from multiple Shigella serotypes. These strains have been characterized for attenuation using both in vivo and in vitro assays. Based on this data, prototypic Shigella vaccine strains containing multiple deletions in virulence-associated genes have been generated.
authors.affiliation: Department of Enteric Infections, Division of Communicable Diseases and Immunology, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA. ryan.ranallo@na.amedd.army.mil
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Ranallo
authors.forename: Shoshana
authors.initials: S
authors.lastname: Barnoy
authors.forename: Sejal
authors.initials: S
authors.lastname: Thakkar
authors.forename: Tonia
authors.initials: T
authors.lastname: Urick
authors.forename: Malabi M
authors.initials: MM
authors.lastname: Venkatesan
mesh_terms: D010582:Bacteriophage lambda / Q000235:genetics*; D017353:Gene Deletion; D005818:Genetic Engineering; D016297:Mutagenesis, Site-Directed / Q000379:methods*; D011995:Recombination, Genetic; D012760:Shigella / Q000235:genetics* / Q000276:immunology* / Q000472:pathogenicity; D022281:Shigella Vaccines; D014774:Virulence / Q000235:genetics
chemical_list: D022281:Shigella Vaccines