title: Formulation and immunogenicity studies of type III secretion system needle antigens as vaccine candidates.
abstract: Bacterial infections caused by Shigella flexneri, Salmonella typhimurium, and Burkholderia pseudomallei are currently difficult to prevent due to the lack of a licensed vaccine. Here we present formulation and immunogenicity studies for the three type III secretion system (TTSS) needle proteins MxiH(Δ5), PrgI(Δ5), and BsaL(Δ5) (each truncated by five residues at its C terminus) as potential candidates for vaccine development. These antigens are found to be thermally stabilized by the presence of carbohydrates and polyols. Additionally, all adsorb readily to aluminum hydroxide apparently through a combination of hydrogen bonds and/or Van der Waals forces. The interaction of these proteins with the aluminum-based adjuvant changes with time resulting in varying degrees of irreversible binding. Peptide maps of desorbed protein, however, suggest that chemical changes are not responsible for this irreversible association. The ability of MxiH(Δ5) and PrgI(Δ5) to elicit strong humoral immune responses was tested in a murine model. When administered intramuscularly as monomers, the needle components exhibited dose dependent immunogenic behavior. The polymerized version of MxiH was exceptionally immunogenic even at low doses. The responses of both monomeric and polymerized forms were boosted by adsorption to an aluminum salt adjuvant.
authors.affiliation: Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, 2030 Becker Drive, Kansas 66047, USA.
authors.forename: Brooke S
authors.initials: BS
authors.lastname: Barrett
authors.forename: Aaron P
authors.initials: AP
authors.lastname: Markham
authors.forename: Reza
authors.initials: R
authors.lastname: Esfandiary
authors.forename: Wendy L
authors.initials: WL
authors.lastname: Picking
authors.forename: William D
authors.initials: WD
authors.lastname: Picking
authors.forename: Sangeeta B
authors.initials: SB
authors.lastname: Joshi
authors.forename: C Russell
authors.initials: CR
authors.lastname: Middaugh
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology / Q000627:therapeutic use*; D001426:Bacterial Proteins / Q000276:immunology / Q000627:therapeutic use*; D001428:Bacterial Vaccines / Q000276:immunology / Q000627:therapeutic use*; D016957:Burkholderia pseudomallei / Q000276:immunology*; D004405:Dysentery, Bacillary / Q000517:prevention & control; D005079:Excipients; D016905:Gram-Negative Bacterial Infections / Q000517:prevention & control*; D006801:Humans; D056724:Immunity, Humoral; D008554:Melioidosis / Q000517:prevention & control; D051379:Mice; D008807:Mice, Inbred BALB C; D055550:Protein Stability; D012480:Salmonella Infections / Q000517:prevention & control; D012486:Salmonella typhimurium / Q000276:immunology*; D012763:Shigella flexneri / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D005079:Excipients; C413572:MxiH protein, Shigella