High frequencies of naive Melan-A/MART-1-specific CD8(+) T cells in a large proportion of human histocompatibility leukocyte antigen (HLA)-A2 individuals. by Pittet, M, Valmori, D, Dunbar, P, Speiser, D, Liénard, D, Lejeune, F, Fleischhauer, K, Cerundolo, V, Cerottini, J, Romero, P