GENERATION OF MELANOMA-SPECIFIC CYTOTOXIC T-LYMPHOCYTES BY DENDRITIC CELLS TRANSDUCED WITH A MART-1 ADENOVIRUS

Dendritic cells (DC) are potent stimulators of primary T cell response s. In this study, we demonstrate that DC, genetically engineered to ex press the MART-1/Melan-A (MART-1) tumor-associated Ag, express MART-1 mRNA and protein, correctly process and present the HLA-A2.1-restricte d immunodominant MART-1 peptide (MART-1(27-35)), and serve as potent s timulators of MART-1-specific CTL in vitro. A replication-defective El -deleted adenovirus (AdV) was constructed that expresses MART-1 (AdVMA RT1), Transduced DC produce full length MART-I mRNA as well as MART-1 protein. AdVMART1 does not significantly down-regulate cell surface cl ass I expression despite having an intact E3 region. Transduction of a n HLA-A2-positive/ MART-I-negative cell line with AdVMART1 renders the se cells sensitive to lysis by CTL specific for the MART-1(27-35) immu nodominant peptide. In addition, DC transduced with AdVMART1 stimulate d MART-1(27-35)-specific tumor-infiltrating lymphocytes to synthesize IFN-gamma, Finally, AdVMART1-transduced DC were able to generate MART- 1(27-35) peptide-specific, class I-restricted CTL in PBL cultures from normal donors. This study supports the use of tumor Ag-engineered DC in genetic immunotherapy.