Presentation of tumor antigens. The role of dendritic cells

Human tumors express a number of protein antigens that can be recognized by T cells, thus providing potential targets for cancer immunotherapy. Dendritic cells are rare leukocytes that are uniquely potent in their ability to present antigens to T cells, and this property has prompted their recent application to therapeutic cancer vaccines. Isolated dendritic cells loaded with tumor antigen ex vivo and administered as a cellular vaccine have been found to induce protective and therapeutic antitumor immunity in experimental animals. In pilot clinical trials of dendritic cells vaccination for patients with non-Hodgkints lymphoma and melanoma, induction of anti-tumor immune responses and tumor regressions have been observed. Additional trials of dendritic cells vaccination for a variety of human cancers are underway, and methods for targeting tumor antigens to dendritic cells in vivo are also being explored. Exploitation of the antigen-presenting properties of dendritic cells thus offers promise for the development of effective cancer immunotherapies.