Dendritic cells loaded with MART-1 peptide or infected with adenoviral construct are functionally equivalent in the induction of tumor-specific cytotoxic T lymphocyte responses in patients with melanoma

Immunization with tumor-specific-associated antigen-pulsed dendritic cells has proved to be efficacious in various animal models and is being evaluate d for the treatment of cancer in humans. Use of dendritic cells pulsed with specific peptides or transfected with tumor-associated antigen genes has b een a focused area of investigation for inducing potent tumor and viral imm une responses. In this study, the authors demonstrate transgene expression, including the lacZ and MART-1 genes, in dendritic cells infected with aden oviral constructs. These transiently transduced dendritic cells, derived fr om melanoma patients' monocytes cultured with granulocyte-macrophage colony -stimulating factor and interleukin-4, express the transgene and can stimul ate patients' CD8(+) T cells to elicit an antitumor immune response compara ble to dendritic cells loaded with a defined peptide. These cytotoxic T lym phocytes were able to recognize both known and unknown tumor-associated ant igen epitopes and exhibited cytolytic activity against HLA-matched tumor ce lls expressing the antigen. The ability to induce tumor-specific cytotoxic T lymphocytes in vitro using gene-modified dendritic cells that transiently express tumor-associated antigens demonstrates the potential use of these antigen-presenting cells for developing in vivo cancer vaccines.