title: Human immune proteome in experimental colonization with Staphylococcus aureus.
abstract: More than 20% of adults are persistently colonized with Staphylococcus aureus. When hospitalized, these carriers have increased risks of infection with their own strains. However, a recent study demonstrated a lower incidence of bacteremia-related death among carriers than among noncarriers, raising the question whether the adaptive immune system plays a protective role. In fact, S. aureus carriers mount a highly specific neutralizing antibody response against superantigens of their colonizing strains. We now used 2-dimensional immunoblotting to investigate the profiles of antibodies from healthy individuals against S. aureus extracellular proteins. Moreover, we tested whether symptom-free experimental colonization of these individuals with an S. aureus strain of low virulence, 8325-4, is sufficient to induce an antibody response. Sera obtained before and 4 weeks after colonization were screened for immunoglobulin G (IgG) antibody binding to extracellular staphylococcal proteins. At baseline, most volunteers harbored IgG directed against conserved virulence factors, including alpha-hemolysin (Hla), beta-hemolysin (Hlb), phospholipase C (Plc), staphylococcal serine protease (SspA), and cysteine protease (SspB). However, the variability of spot patterns and intensities was striking and could be important in case of infection. Experimental nasal colonization with S. aureus 8325-4 did not elicit new antibodies or boost the humoral response. Thus, the high antibody prevalence in humans is likely not induced by short-term nasal colonization, and presumably minor infections are required to trigger anti-S. aureus antibody responses.
authors.affiliation: Institute of Immunology and Transfusion Medicine, University of Greifswald, Greifswald, Germany.
authors.forename: Silva
authors.initials: S
authors.lastname: Holtfreter
authors.forename: Thi Thu Hoai
authors.initials: TT
authors.lastname: Nguyen
authors.forename: Heiman
authors.initials: H
authors.lastname: Wertheim
authors.forename: Leif
authors.initials: L
authors.lastname: Steil
authors.forename: Harald
authors.initials: H
authors.lastname: Kusch
authors.forename: Quoc Phong
authors.initials: QP
authors.lastname: Truong
authors.forename: Susanne
authors.initials: S
authors.lastname: Engelmann
authors.forename: Michael
authors.initials: M
authors.lastname: Hecker
authors.forename: Uwe
authors.initials: U
authors.lastname: Völker
authors.forename: Alex
authors.initials: A
authors.lastname: van Belkum
authors.forename: Barbara M
authors.initials: BM
authors.lastname: Bröker
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D002353:Carrier State / Q000276:immunology*; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D005260:Female; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D020543:Proteome / Q000032:analysis*; D013203:Staphylococcal Infections / Q000276:immunology*; D013211:Staphylococcus aureus / Q000276:immunology*; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D020543:Proteome