1. Department of Virology, Faculty of Medicine, Imperial College London, Norfolk Place, London W2 1PG, UK
2. EBV Biology Laboratory, Division of Immunology and Infectious Diseases, Queensland Institute of Medical Research, Herston, QLD 4006, Australia
3. Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0440, USA