1. Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
2. Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom
3. Division of Retrovirology, NIBSC, Health Protection Agency, South Mimms, Potters Bar, United Kingdom
4. Jefferiss Research Laboratories, Faculty of Medicine, Imperial College London, St. Mary's Campus, London, United Kingdom