title: Advantages of a synthetic peptide immunogen over a protein immunogen in the development of an anti-pilus vaccine for Pseudomonas aeruginosa.
abstract: The type IV pilus is an important adhesin in the establishment of infection by Pseudomonas aeruginosa. We have previously reported on a synthetic peptide vaccine targeting the receptor-binding domain of the main structural subunit of the pilus, PilA. The receptor-binding domain is a 14-residue disulfide loop at the C-terminal end of the pilin protein. The objective of this study was to compare the immunogenicity of a peptide-conjugate to a protein subunit immunogen to determine which was superior for use in an anti-pilus vaccine. BALB/c mice were immunized with the native PAK strain pilin protein and a synthetic peptide of the receptor-binding domain conjugated to keyhole limpet haemocyanin. A novel pilin protein with a scrambled receptor-binding domain was used to characterize receptor-binding domain-specific antibodies. The titres against the native pilin of the animals immunized with the synthetic peptide-conjugate were higher than the titres of animals immunized with the pilin protein. In addition, the affinities of anti-peptide sera for the intact pilin receptor-binding domain were significantly higher than affinities of anti-pilin protein sera. These results have significant implications for vaccine design and show that there are significant advantages in using a synthetic peptide-conjugate over a subunit pilin protein for an anti-pilus vaccine.
authors.affiliation: Department of Biochemistry and Molecular Genetics, University of Colorado Denver, School of Medicine, Biomolecular Structure, MS 8101, P.O. Box 6511, Aurora, CO 80045, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Kao
authors.forename: Robert S
authors.initials: RS
authors.lastname: Hodges
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D036781:Fimbriae Proteins / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D054406:Pseudomonas Vaccines / Q000032:analysis / Q000276:immunology*; D011550:Pseudomonas aeruginosa / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology / Q000302:isolation & purification; D018074:Vaccines, Conjugate / Q000032:analysis / Q000276:immunology
chemical_list: D010455:Peptides; D054406:Pseudomonas Vaccines; D011994:Recombinant Proteins; D018074:Vaccines, Conjugate; D036781:Fimbriae Proteins