1. The Genomics Institute of Novartis Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121, USA.
2. Novartis Vaccines, 45 Sidney Street, Cambridge, MA 02139, USA.
3. Novartis Vaccines, Via Florentina 1, 53100 Siena, Italy.
4. U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA.