1. Haartman Institute (K.P., O.S.), Helsinki, Finland
2. Department of Virology, and Biomedicum Helsinki (K.P., O.S.), Programme for Developmental and Reproductive Biology, FIN-00014 University of Helsinki, Helsinki, Finland
3. Institute of Medical Technology (J.Y., O.S.), University of Tampere; FIN-33014 Tampere, Finland
4. Department of Clinical Microbiology (O.S.), Tampere University Hospital, FIN-33014 Tampere, Finland