Dendritic cells for specific cancer immunotherapy

The characterization of tumor-associated antigens recognized by human T lym phocytes in a major histocompatibility complex (MHC)-restricted fashion has opened new possibilities for immunotherapeutic approaches to the treatment of human cancers. Dendritic cells (DC) are professional antigen presenting cells that are well suited to activate T cells toward various antigens, su ch as tumor-associated antigens, due to their potent costimulatory activity . The availability of large numbers of DC, generated either from hematopoie tic progenitor cells or monocytes in vitro or isolated from peripheral bloo d, has profoundly changed pre-clinical research as well as the clinical eva luation of these cells. Accordingly, appropriately pulsed or transfected DC may be used for vaccination in the field of infectious diseases or tumor i mmunotherapy to induce antigen-specific T cell responses. These observation s led to pilot clinical trials of DC vaccination for patients with cancer i n order to investigate the feasibility, safety, as well as the immunologic and clinical effects of this approach. Initial clinical studies of human DC vaccines are generating encouraging preliminary results demonstrating indu ction of tumor-specific immune responses and tumor regression. Nevertheless , much work is still needed to address several variables that are critical for optimizing this approach and to determine the role of DC-based vaccines in tumor immunotherapy.