1. Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710
2. Trimeris Pharmaceuticals, Durham, North Carolina 27707
3. Harvard School of Public Health, Boston, Massachusetts 02115
4. Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710
5. Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina 27599
6. Department of Pathology, University of Alabama, Birmingham, Alabama 35294