Department of Microbiology and Immunology, Rega Institute, KU Leuven, Leuven, Belgium. guy.baele@rega.kuleuven.be|Department of Microbiology and Immunology, Rega Institute, KU Leuven, Leuven, Belgium. guy.baele@rega.kuleuven.be|Department of Microbiology and Immunology, Rega Institute, KU Leuven, Leuven, Belgium. guy.baele@rega.kuleuven.be