Peter J. Delves PhD Division of Infection and Immunity UCL, London, UK Seamus J. Martin PhD, FTCD, MRIA The Smurfit Institute of Genetics Trinity College, Dublin, Ireland Dennis R. Burton PhD Department of Immunology and Microbial Science The Scripps Research Institute La Jolla, California, USA Ivan M. Roitt MA, DSc(Oxon), FRCPath, Hon FRCP (Lond), FRS Centre for Investigative and Diagnostic Oncology Middlesex University, London, UK