Dendritic cells presenting tumor antigen.

Since the first identification of dendritic cells by Steinman and Cohn in 1973, progress in understanding their biology has included the development of novel methods of cell culture, recognition of critical aspects of migration and maturation, and appreciation of their major role as antigen-presenting cells (APC), and how this activity is regulated by cytokines and expression of accessory molecules. Dendritic cells are the major APC involved in the initiation of the immune response and the development of tolerance. There is considerable evidence that they can acquire antigen in the peripheral tissues and process, transport, and present it to T cells in secondary lymphoid tissue. A number of studies show that, in vitro or in vivo, antigen-pulsed dendritic cells can directly sensitize T cells and stimulate the development of antigen-specific immune responses, including both protective and therapeutic antitumor responses. In this paper, several important aspects of dendritic cell biology are discussed and a number of studies confirming the role of these professional APC in antitumor immunity are reviewed.