We would like to thank Gerhard Jahn and Thomas Iftner for constant support and encouragement and Ulrike Protzer for providing continued access to the research facilities at the Helmholtz Center Munich. Furthermore, we thank Daniel Sauter, Paul Bieniasz, and Thomas Gramberg for providing reagents and Thomas Hoenen for the trVLP system. This work was funded by grants to S.P. and M. Schindler from Deutsche Forschungsgemeinschaft (SCHI 1073/4-1 and PO 716/8-1). Furthermore, M. Schindler received institutional support from the Helmholtz Center Munich, German Research Center for Environmental Health, and the University Hospital Tuebingen.