1. Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
2. Division of Molecular Medicine, Children's Hospital, and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
3. Theoretical Biology and Biophysics, Los Alamos National Laboratory, and the New Mexico Consortium, Los Alamos, New Mexico, USA
4. Crucell Vaccine Institute, Leiden, The Netherlands
5. Ragon Institute of MGH, MIT, and Harvard, Boston, Massachusetts, USA