Peter J. Delves PhDDivision of Infection and ImmunityUCL, London, UKSeamus J. Martin PhD, FTCD, MRIAThe Smurfit Institute of GeneticsTrinity College, Dublin, IrelandDennis R. Burton PhDDepartment of Immunology and Microbial ScienceThe Scripps Research InstituteLa Jolla, California, USAIvan M. Roitt MA, DSc(Oxon), FRCPath, Hon FRCP (Lond), FRSCentre for Investigative and Diagnostic OncologyMiddlesex University, London, UK