Gene transfer to dendritic cells induced a protective immunity against melanoma.

Lentiviral vectors have shown promises for efficient gene transfer to dividing as well as nondividing cells. In this study, we explored lentiviral vector-mediated, the entire mTRP-2 gene transfer and expression in dendritic cells (DCs). Adoptive transfer of DCs-expressing mTRP-2 (DC-HR'CmT2) into C57BL/6 mouse was also assessed. Dendritic cells were harvested from bone marrow and functional DCs were proved by allogeneic mixed lymphocyte reaction. Lentiviral vectors were produced by transient transfection of 293T cells. Transduction of DCs was proved by marker gene expression and PCR and RT-PCR amplification. Implantation of the transduced DCs, depletion of immune cells as well as the survival of the mice after tumour challenge were investigated. High efficiency of gene transfer into mature DCs was achieved. The high level expression of the functional antigen (TRP-2) and induction of protective immunity by adoptive transfer of TRP-2 gene modified DCs were demonstrated. In vivo study showed a complete protection of mice from further melanoma cell challenge. In comparison, only 83% of mice survived when mTRP-2 peptide-pulsed DCs were administered, suggesting the generation of specific protection. Together, these results demonstrated the usefulness of this gene transfer to DC approach for immunotherapy of cancer and indicated that using tumour associated antigens (TAAs) for gene transfer may be potentially beneficial for the therapy of melanoma.