Figure 1.

Dendritic cells (DCs) readapted taxonomy. Newly identified populations of blood human DCs are shown. DC1 subset is clearly distinct by the expression of CLEC9A, and it is specialized in cross-presentation of ags. DC2 and DC3 constitute the conventional DCs pool, even though they appear to be phenotypically slightly different and, upon stimulation with TLR ligands, their diversity emerges. DC4 is a population characterized by an upregulated Type I Interferon pathway for antiviral responses. DC5 has emerged as a new population whose specific functions are still unexplored. DC6 corresponds to the classic plasmacytoid DCs. These advances in the fine characterization of DCs in humans may shed light on the best subset to be targeted to incentivize the desired immune response.