title: Regulation of Vi capsular polysaccharide synthesis in Salmonella enterica serotype Typhi.
abstract: The synthesis of Vi polysaccharide, a major virulence determinant in Salmonella enterica serotype Typhi (S. Typhi), is under the control of two regulatory systems, ompR-envZ and rscB-rscC, which respond to changes in osmolarity. Some S. Typhi isolates exhibit over-expression of Vi polysaccharide, which masks clinical detection of LPS O-antigen. This variation in Vi polysaccharide and O-antigen display (VW variation) has been observed since the initial studies of S. Typhi. We have reported that the status of the rpoS gene is responsible for this phenomenon. We review the regulatory network of the Vi polysaccharide, linking osmolarity and RpoS expression. Also, we discuss how this may impact live attenuated Salmonella vaccine development.
authors.affiliation: Center for Infectious Diseases and Vaccinology, The Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, Arizona 85287-5401, United States of America.
authors.forename: Javier
authors.initials: J
authors.lastname: Santander
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Roland
authors.forename: Roy
authors.initials: R
authors.lastname: Curtiss
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D006801:Humans; D019081:O Antigens / Q000378:metabolism; D009994:Osmolar Concentration; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D022562:Salmonella Vaccines / Q000627:therapeutic use; D012485:Salmonella typhi / Q000378:metabolism* / Q000472:pathogenicity; D012808:Sigma Factor / Q000378:metabolism; D014435:Typhoid Fever / Q000378:metabolism / Q000382:microbiology* / Q000517:prevention & control; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D019081:O Antigens; D011135:Polysaccharides, Bacterial; D022562:Salmonella Vaccines; D012808:Sigma Factor; C054154:capsular polysaccharide, Salmonella; C069567:sigma factor KatF protein, Bacteria