Dendritic cells: directors of the immune system orchestra

irst observed in 1868 as Langerhans’ cells of the epidermis and then brought to attention again 25 years ago by Steinman and colleagues, dendritic cells (DC) remained enigmatic due to their scarcity and difficulties in isolation. Owing to the development of methods allowing in vitro DC generation, a wealth of information regarding their biology recently has been accumulated. Dendritic cells are now recognized as an integral part of the lymphohematopoietic system. Distributed as sentinels throughout the body, DC are poised to capture antigen, migrate to draining lymphoid organs, and, after a process of maturation, select antigen-specific lymphocytes to which they present the processed antigen, thereby initiating immune responses (Figure 1).