1. Institute of Virology, Medical Center University of Freiburg, Freiburg, Germany.
2. Institute of Medical Microbiology and Hygiene, Medical Center University of Freiburg, Freiburg, Germany.
3. Würzburg Institute of Systems Immunology, University of Würzburg, Würzburg, Germany.
4. Medical Faculty, University of Freiburg, Freiburg, Germany.