Major histocompatibility complex class I restricted cytotoxic T cells specific for natural melanoma peptides recognize unidentified shared melanoma antigen(s)

CTLs were generated in vitro from two healthy donors and one melanoma patie nt by stimulation of CD8(+) T cells with autologous dendritic cells pulsed with natural melanoma peptides (NMPs), obtained by acid treatment of HLA-ma tched melanoma cells. CTLs showed MHC class I-restricted melanoma-specific cytolytic activity. Importantly, CTLs from the patient, induced with NMPs o btained from an allogeneic HLA-A-matched melanoma, killed the autologous tu mor. COS-7 cells cotransfected with the cDNA of 13 melanoma antigens and th e HLA-A1-restricting allele did not induce cytokines release from NMP-speci fic CTLs, suggesting that they recognize unidentified shared melanoma antig ens and that they may be valuable for identification of new tumor antigens, These results strongly support the use of autologous and/or allogeneic NMP -pulsed dendritic cells as cancer vaccines in patients whose neoplasms do n ot express or have lost expression of known tumor antigens.