Mage-3 and influenza-matrix peptide-specific cytotoxic T cells are inducible in terminal stage HLA-A2.1+ melanoma patients by mature monocyte-derived dendritic cells.
Schuler-Thurner B., Dieckmann D., Keikavoussi P., Bender A., Maczek C., Jonuleit H., Röder C., Haendle I., Leisgang W., Dunbar R., Cerundolo V., von Den Driesch P., Knop J., Bröcker EB., Enk A., Kämpgen E., Schuler G.
Dendritic cell (DC) vaccination, albeit still in an early stage, is a promising strategy to induce immunity to cancer. We explored whether DC can expand Ag-specific CD8+ T cells even in far-advanced stage IV melanoma patients. We found that three to five biweekly vaccinations of mature, monocyte-derived DC (three vaccinations of 6 x 106 s.c. followed by two i.v. ones of 6 and 12 x 106, respectively) pulsed with Mage-3A2.1 tumor and influenza matrix A2. 1-positive control peptides as well as the recall Ag tetanus toxoid (in three of eight patients) generated in all eight patients Ag-specific effector CD8+ T cells that were detectable in blood directly ex vivo. This is the first time that active, melanoma peptide-specific, IFN-gamma-producing, effector CD8+ T cells have been reliably observed in patients vaccinated with melanoma Ags. Therefore, our DC vaccination strategy performs an adjuvant role and encourages further optimization of this new immunization approach.