Dendritic cells: nearly 40 years later…

The immune system is probably one of the most complex cellular organizations in the body. Its complexity is not superfluous, but rather it is required to fulfill the complicated purpose of the immune system, namely: the recognition of the diverse repertoire of microorganisms and pathogens; the detection of neoplastic lesions originating from a range of tissues; and, while executing these tasks, the maintenance of peripheral tolerance by suppressing detrimental responses against healthy tissues. Since they were discovered by R. Steinman et al. nearly 40 years ago, dendritic cells (DCs) have emerged to be critical players in conducting the immune response to fulfill these roles. Here, we provide a general view on some aspects of DC immunology, highlighting the crucial role that R. Steinman's research in the DC field has played during all those years. This review will also give an outline on DC research in the particular aspects that represent the focus of research groups in Spain (recently organized as the DC.esp working group within SEI). Firstly, some of the subtypes of DC will be described, particularly thymic DC and their role on tolerance; then the DC role in tolerance will be examined, followed by their implications in viral infections. Finally, antigen targeting DCs will be reviewed taking into account the crucial contributions made by R. Steinman et al. This chapter will end by reviewing some DCs based therapies in viral infections.