A HLA-A2 restricted human CTL line recognizes a novel tumor cell expressed p53 epitope.
A p53 peptide-specific CTL line was generated through stimulation with autologous monocyte-derived dendritic cells (DC) pulsed with wild-type HLA-A2 binding p53 derived peptides. A p53 peptide-specific CD8(+) CTL line was established from a healthy HLA-A2 positive donor. The CTL line was characterized with respect to specificity, affinity and killing of cell lines derived from p53 mutated spontaneous tumors. The CTL line demonstrated lysis of p53(139-147) pulsed target cells and cold target inhibition experiments as well as antibody blocking confirmed that the killing was epitope-specific, HLA-A2 restricted and dependent on CD8-binding. Interestingly, the affinity of the CTL line was only in the micromole per liter range and target cells pulsed with less than 0.01 microM peptide were not recognized. Furthermore, 3 HLA-A2(+) p53 mutated tumor cell lines were efficiently lysed by the CTL line, indicating that this novel p53 peptide epitope is endogenously processed and presented by the HLA-A2 molecules of the tumor cells. In conclusion, CTL reactivity towards a wild-type p53 peptide was revealed through induction with DC pulsed with a pool of HLA-A2 binding p53 peptides. In addition, the CTL line, which expressed relatively low affinity for the HLA-A2/peptide complex, was able to kill 3 different HLA-A2(+) p53 mutated tumor cell lines. The present and our previous observations expand the number of p53-derived peptides suitable for vaccination protocols for cancer patients with p53 positive tumors.
Würtzen
Peter A
PA
Department of Medical Anatomy, The Panum Institute, University of Copenhagen, Copenhagen, Denmark. paw@dk.alk-abello.com
Claesson
Mogens H
MH
D016827:CD8 Antigens / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D000939:Epitopes; D016158:Genes, p53; D015789:HLA-A2 Antigen / Q000096:biosynthesis*; D006801:Humans; D009154:Mutation; D010455:Peptides / Q000737:chemistry; D010641:Phenotype; D011485:Protein Binding; D013602:T-Lymphocytes, Cytotoxic / Q000378:metabolism; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry*; D015854:Up-Regulation
D016827:CD8 Antigens; D000939:Epitopes; D015789:HLA-A2 Antigen; D010455:Peptides; D016159:Tumor Suppressor Protein p53