title: Reply.
authors.affiliation: Centre for Immunobiology, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, United Kingdom.
authors.forename: Patrick T F
authors.initials: PTF
authors.lastname: Kennedy
authors.affiliation: Emerging Infectious Diseases Program, Duke-National University of Singapore Graduate Medical School, Singapore.
authors.forename: Antonio
authors.initials: A
authors.lastname: Bertoletti
authors.affiliation: Fox Chase Cancer Center, Philadelphia, Pennsylvania.
authors.forename: William S
authors.initials: WS
authors.lastname: Mason