title: Use of the alpha-hemolysin secretion system of Escherichia coli for antigen delivery in the Salmonella typhi Ty21a vaccine strain.
abstract: This study examined the suitability of the hemolysin secretion system of Escherichia coli for expression and delivery of alpha-hemolysin (HlyA) by the S. typhi Ty21a strain, the only live oral Salmonella vaccine strain licensed for human use, under in vitro and in vivo conditions. For this purpose, two plasmid vectors encoding either the whole alpha-hemolysin of E. coli (pANN202-812/pMOhly2) or the hemolysin secretion signal (pMOhly1) were transferred into S. typhi Ty21a. S. typhi Ty21a carrying pANN202-812/pMOhly2 revealed efficient secretion of hemolysin in vitro. After formulation according to a process suitable for commercial production of Salmonella-based live bacterial vaccines, plasmids were shown to be stable in Ty21a and hemolysin secretion was demonstrated even after storage of the strains under real-time and stress conditions. After intranasal immunization of mice with S. typhi Ty21a/pANN202-812 plasmids are stable in vivo, and immunization induced a profound immune response against the heterologous HlyA antigen. Therefore, the combination of the hemolysin secretion system and S. typhi Ty21a could form the basis for a new generation of live bacterial vaccines.
authors.affiliation: Institut für Medizinische Strahlenkunde und Zellforschung, University of Würzburg, Versbacher Str. 5, D-97078 Würzburg, Germany. ivaylo.gentschev@mail.uni-wuerzburg.de
authors.forename: Ivaylo
authors.initials: I
authors.lastname: Gentschev
authors.forename: Guido
authors.initials: G
authors.lastname: Dietrich
authors.forename: Simone
authors.initials: S
authors.lastname: Spreng
authors.forename: Beatrice
authors.initials: B
authors.lastname: Neuhaus
authors.forename: Elke
authors.initials: E
authors.lastname: Maier
authors.forename: Roland
authors.initials: R
authors.lastname: Benz
authors.forename: Werner
authors.initials: W
authors.lastname: Goebel
authors.forename: Joachim
authors.initials: J
authors.lastname: Fensterle
authors.forename: Ulf R
authors.initials: UR
authors.lastname: Rapp
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D005822:Genetic Vectors; D006460:Hemolysin Proteins / Q000235:genetics / Q000276:immunology*; D007114:Immunization; D051379:Mice; D008810:Mice, Inbred C57BL; D010957:Plasmids; D022562:Salmonella Vaccines / Q000008:administration & dosage* / Q000235:genetics; D012485:Salmonella typhi / Q000235:genetics / Q000378:metabolism*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D029968:Escherichia coli Proteins; D006460:Hemolysin Proteins; C036507:Hlya protein, E coli; D022562:Salmonella Vaccines