Dendritic cells (DCs) are potent antigen-presenting cells (APCs) that play a pivotal role in stimulating antigen-specific T cells in vivo (1 ,2 ). The cardinal properties of DCs are: (1) the ability to take up, process, and present antigens; (2) the ability to migrate through different tissues into lymphoid organs; and (3) the ability to interact with and stimulate T cells (3 ). Because of their unique capability of generating primary CD4+ and CD8+ T-cell responses, DCs are of particular interest for immunotherapeutic approaches to infectious disease and cancer.