1. Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University, Cambridge, MA 02139, USA.
2. Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA.
3. AIDS and Cancer Virus Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA.
4. Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
5. Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20814, USA.
6. The Scripps Research Institute, La Jolla, CA 92037, USA.
7. National Institute for Communicable Diseases of the National Health Laboratory Service and the University of the Witwatersrand, 2131 Johannesburg, South Africa.
8. Centre for the AIDS Programme of Research in South Africa, 4013 Durban, South Africa.
9. Columbia University, New York, NY 10032, USA.