title: Functional selection of vaccine candidate peptides from Staphylococcus aureus whole-genome expression libraries in vitro.
abstract: An in vitro protein selection method, ribosome display, has been applied to comprehensively identify and map the immunologically relevant proteins of the human pathogen Staphylococcus aureus. A library built up from genomic fragments of the virulent S. aureus COL strain (methicillin-resistant S. aureus) allowed us to screen all possible encoded peptides for immunoreactivity. As selective agents, human sera exhibiting a high antibody titer and opsonic activity against S. aureus were used, since these antibodies indicate the in vivo expression and immunoreactivity of the corresponding proteins. Identified clones cluster in distinct regions of 75 genes, most of them classifiable as secreted or surface-localized proteins, including previously identified virulence factors. In addition, 14 putative novel short open reading frames were identified and their immunoreactivity and in vivo mRNA expression were confirmed, underscoring the annotation-independent, true genomic nature of our approach. Evidence is provided that a large fraction of the identified peptides cannot be expressed in an in vivo-based surface display system. Thus, in vitro protein selection, not biased by the context of living entities, allows screening of genomic expression libraries with a large number of different ligands simultaneously. It is a powerful approach for fingerprinting the repertoire of immune reactive proteins serving as target candidates for active and passive vaccination against pathogens.
authors.affiliation: Intercell AG, 1030 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Weichhart
authors.forename: Markus
authors.initials: M
authors.lastname: Horky
authors.forename: Johannes
authors.initials: J
authors.lastname: Söllner
authors.forename: Susanne
authors.initials: S
authors.lastname: Gangl
authors.forename: Tamàs
authors.initials: T
authors.lastname: Henics
authors.forename: Eszter
authors.initials: E
authors.lastname: Nagy
authors.forename: Andreas
authors.initials: A
authors.lastname: Meinke
authors.forename: Alexander
authors.initials: A
authors.lastname: von Gabain
authors.forename: Claire M
authors.initials: CM
authors.lastname: Fraser
authors.forename: Steve R
authors.initials: SR
authors.lastname: Gill
authors.forename: Martin
authors.initials: M
authors.lastname: Hafner
authors.forename: Uwe
authors.initials: U
authors.lastname: von Ahsen
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics* / Q000276:immunology*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D000939:Epitopes / Q000235:genetics; D015723:Gene Library; D016680:Genome, Bacterial; D006801:Humans; D066298:In Vitro Techniques; D016366:Open Reading Frames; D019151:Peptide Library; D010455:Peptides / Q000235:genetics / Q000276:immunology; D013209:Staphylococcal Vaccines / Q000235:genetics* / Q000302:isolation & purification; D013211:Staphylococcus aureus / Q000235:genetics* / Q000276:immunology* / Q000472:pathogenicity
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D000939:Epitopes; D019151:Peptide Library; D010455:Peptides; D013209:Staphylococcal Vaccines