1. Center for Infectious Disease and Vaccine Research, University of Massachusetts, Worcester, Massachusetts.
2. Department of Medicine, Yale University School of Medicine, New Haven, Connecticut.
3. Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas.
4. Infectious Disease Program, Lovelace Research Institute, Albuquerque, New Mexico.
5. Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio.
6. Departments of Medicine and Microbiology/Immunology, Dartmouth Medical School, Lebanon, New Hampshire.