Tumor antigen-specific T cells and cancer immunotherapy: current issues and future prospects.

The critical role of antigen-specific T cells in the eradication of cancer has been demonstrated in numerous animal models. Data compiled from both in vitro systems and human clinical trials indicate that T cells can be identified that recognize antigenic fragments derived from gene products expressed by tumors. Nonetheless, results from clinical trials have been for the most part disappointing, since vaccine protocols designed to elicit anti-tumor T cell activity have, in the majority of cases, failed to result in tumor eradication and enhanced patient survival. The focus of this review article is to summarize the current status of antigen-specific tumor immunotherapy and provide insight into potential future strategies for the successful activation of T cells for the immunotherapy of cancer.