Recognition of MART-1/Melan-A peptide on 3d mDC and 7d mDC by MART-1/Melan-A-specific CTL. (A) 3d mDC and 7d mDC were exogenously loaded with 10 μg/ml short MART-1/Melan-A26-35 peptide for 2 h or 24 h at 37°C and 5% CO2. After washing, the peptide-loaded DC were cocultured with MART-1/Melan-A-specific A42 CTL for 24 h at 37°C and 5% CO2. MART-1/Melan-A-positive tumor cells (Mel-93.04A12) and MART-1/Melan-A-negative tumor cells (Mel A375) served as controls and were cocultured with A42 CTL at the same time points as the DC (2 h and 24 h). The IFN-γ release of A42 CTL was measured by IFN-γ-ELISA. The columns show mean values of triplicates with standard deviations. Data are representative for two experiments. (B) 3d mDC and 7d mDC were incubated with different amounts of long MART-1/Melan-A peptide for 24 h at 37°C and 5% CO2. The DC were cocultured with A42 CTL for additional 24 h. The IFN-γ release of A42 CTL was measured by IFN-γ-ELISA. The columns show mean values of duplicates with standard deviations. The data for 2.5 μg/ml are representative for two independent experiments (n.d.: not detected).