[1] Leiden Univ, LACDR, Div Drug Delivery Technol, NL-2333 CC Leiden, Netherlands
[2] Natl Inst Publ Hlth & Environm, NL-3720 BA Bilthoven, Netherlands
[3] Univ Groningen RuG, Dept Pharmaceut Technol & Biopharm, Groningen, Netherlands
[4] Univ Iowa, Dept Microbiol, Iowa City, IA 52242 USA
[5] Univ Amsterdam, Acad Med Ctr, Dept Resp Med, Div Expt Immunol, NL-1105 AZ Amsterdam, Netherlands
[6] Univ Med Ctr Groningen, Mol Virol Sect, Dept Med Microbiol, NL-9713 AV Groningen, Netherlands
[7] Univ Groningen, Groningen, Netherlands