1. Cancer Biology Division, Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
2. Department of Chemical and Pharmaceutical Biology, University of Groningen, Groningen 9700 AB, The Netherlands
3. Emory Vaccine Center and Yerkes National Primate Research Center, Emory University, Atlanta, Georgia 30322, United States
4. Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, Georgia 30322, United States