Brief Definitive Report Peptide-pulsed Dendritic Cells Induce Antigen-specific, CTL-mediated Protective Tumor Immunity

Cytotoxic T lymphocytes (CTLs) are a critical component o f the immune response to tumors. Tumor-derived peptide antigens targeted by CTLs are being defined for several human tumors and are potential imrnunogens for the induction o f specific antitumor immunity. Dendritic cells (DC) are potent antigen-presenting cells (APCs) capable o f priming CTL responses in vivo. Here we show that major histocompatibility complex class I-presented peptide antigen pulsed onto dendritic APCs induces protective immunity to lethal challenge by a tumor transfected with the antigen gene. The immunity is antigen specific, requiring expression of the antigen gene by the tumor target, and is eliminated by in vivo depletion o f CD8 + T cells. Furthermore, mice that have rejected the transfected tumor are protected from subsequent challenge with the untransfected parent tumor. These results suggest that immunization strategies using antigen-pulsed D C may be useful for inducing tumor-specific immune responses.