Abstracts (complete list) - Wissenschaft Online

Thi Thu Hoai Nguyen, Silva Holtfreter, Thi Thu Hong Le, Harald Kusch, Michael
Hecker, Susanne Engelmann, Alex van Belkum, Uwe Völker, Heiman Wertheim, Barbara
M. Bröker
Human antibody response to experimental colonization with
Staphylococcus aureus
Thi Thu Hoai Nguyen1, Silva Holtfreter1, Thi Thu Hong Le2, Anne-Kathrin Ziebandt3,
Harald Kusch3, Quoc Phong Truong2, Leif Steil2, Michael Hecker3, Susanne
Engelmann3, Alex van Belkum4, Uwe Völker2, Heiman Wertheim4,5, Barbara M.
Bröker1
1) Department of Immunology, University of Greifswald, Germany
2) Department of Functional Genomics, University of Greifswald, Germany
3) Institute of Microbiology and Molecular Biology, University of Greifswald, Germany
4) Department of Medical Microbiology and Infectious Diseases, University Medical
Center, Rotterdam, The Netherlands
5) Oxford University Clinical Research Unit National Institute of Infectious and Tropical
Diseases Bach Mai Hospital, Hanoi, Vietnam
Staphylococcus aureus (S. aureus) is the most common cause of nosocomial infections
and it can cause a wide range of human diseases ranging from superficial abscesses and
wound infections to systemic infections, such as osteomyelitis, infective endocarditis,
and sepsis. At the same time, the microorganism is also a frequent colonizer among the
normal human flora. In S. aureus carriers we found a strong neutralizing antibody
response against superantigens secreted by their colonizing strain. It is not known how
the adaptive immune response against S. aureus proteins is triggered. We colonized 16
healthy volunteers with the S. aureus strain 8325-4, which was selected because of its
low virulence, and obtained serum samples before and four weeks after colonization. To
investigate whether colonization induces changes in the antibody profiles against S.
aureus, we separated the secreted staphylococcal proteins by two-dimensional gel
electrophoresis, transferred them onto a PVDF membrane and afterwards performed
immunoblots with the human sera. The results show a large inter-individual variability
in the antibody profiles against S. aureus 8325-4. Even before experimental
colonization, healthy individuals harboured high titre antibodies directed against a broad
range of extracellular S. aureus proteins. These antibodies are likely due to previous
encounters with S. aureus. Only rarely we observed additional antibody signals or
increased signal intensities after experimental colonization with S. aureus. Therefore,
short term colonization per se does not appear to trigger strong antibody responses to
S. aureus. We conclude that the high antibody titres seen in most healthy individuals, in
particular in S. aureus carriers, require either long lasting contact with S. aureus or,
most likely, minor infections as they commonly occur with this microorganism,
especially with strains of higher invasive potential.