1. University of North Carolina HIV Cure Center, Department of Medicine, and Center for AIDS Research, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA.
2. Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA.
3. Merck Research Laboratories, White Horse Junction, PA, USA.
4. Duke Human Vaccine Institute, Department of Medicine, and Department of Immunology, Duke University School of Medicine, Durham, NC, USA.