title: Specific killing of P53 mutated tumor cell lines by a cross-reactive human HLA-A2-restricted P53-specific CTL line.
abstract: p53 is upregulated in the majority of spontaneous tumors and the HLA class I molecule HLA-A2 is expressed by approximately 50% of the caucasians. Potentially, these facts make HLA-A2-binding p53 peptides for CTL-inducing immunotherapy applicable to a broad range of cancer patients. In our study, we investigated the CTL-inducing capacity of autologous monocyte-derived dendritic cells (DC) maturated by exposure to CD40L and pulsed with a pool of 4 wild-type, HLA-A2-binding p53 peptides, and the p53-specific CD8(+) CTL lines established from healthy HLA-A2-positive donors were characterized. Reactivity to p53(65-73) and p53(187-197) peptides was obtained in the T-cell lines. Interestingly, cold target inhibition experiments demonstrated that the simultaneous recognition of the 2 peptides was the result of cross-reactivity, which was confirmed by killing experiments at the clonal CTL level. Furthermore, 4 HLA-A2(+) p53-mutated tumor cell lines were lysed by the CTL line, indicating that these peptides are endogenously processed and presented on HLA-A2 molecule. Thus, monocyte-derived DC pulsed with a pool of peptides are able to induce CTL reactivity to wild-type p53 peptides presented by several cancer cell lines. In addition, the recognition of 2 different p53 peptides by the same CTL clone suggests a promiscuous peptide recognition by the TCR involved. Taken together, these in vitro results suggest that vaccination with autologous DC pulsed with multiple p53 epitopes may induce an effective tumor-specific CTL response in vivo with the potential to eradicate p53-upregulated spontaneously occurring tumors.
authors.affiliation: Department of Medical Anatomy, The Panum Institute, University of Copenhagen, Copenhagen, Denmark. P.Wurtzen@server.mai.ku.dk
authors.forename: P A
authors.initials: PA
authors.lastname: Würtzen
authors.forename: L O
authors.initials: LO
authors.lastname: Pedersen
authors.forename: H S
authors.initials: HS
authors.lastname: Poulsen
authors.forename: M H
authors.initials: MH
authors.lastname: Claesson
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D002460:Cell Line; D003713:Dendritic Cells / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D000939:Epitopes; D016158:Genes, p53 / Q000235:genetics*; D015789:HLA-A2 Antigen / Q000235:genetics*; D006801:Humans; D009154:Mutation; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
chemical_list: D000939:Epitopes; D015789:HLA-A2 Antigen; D010455:Peptides