Dendritic Cells

Abstract

Dendritic cells (DCs) are distributed in almost all tissues body, acting as sentinels of the immune system. They serve as specialised pathogen‐sensing and antigen‐presenting cells that initiate and regulate the immune response. DCs are derived from unique progenitors present in the bone marrow, which seed the tissues where they differentiate into mature DCs. Transcriptomic, phenotypic and functional analyses indicate that human and murine DCs can be divided into three subsets: two subsets of conventional DCs (cDC) named cDC1 and cDC2, and a third lineage of plasmacytoid DCs (pDCs). Each subset is unique and has distinct functional specialisations to control specific T‐cell responses. DCs form a complex cellular network capable of integrating multiple environmental signals and can induce either immunity or tolerance. As a consequence, DCs are suitable candidates for therapeutic intervention in immune‐mediated conditions. Key Concepts Dendritic cells are a heterogeneous group of specialised pathogen‐sensing and antigen‐presenting cells. They are distributed in almost all tissues and organs, and act as sentinels of the immune system. They are derived from DC‐restricted progenitors present in the bone marrow and arise from a dedicated lineage. They can be grouped into three subsets based on ontogeny and transcription factor dependency: two lineages of conventional DCs named cDC1 and cDC2, as well as a third lineage of plasmacytoid DCs (pDCs). Each subset is unique and has distinct functional specialisations. The cDC1 subset is efficient at cross‐presentation, and elicits Th1 responses. The cDC2 subset is capable of eliciting Th2 and Th17 responses. pDCs produce large amounts of type I interferons to combat viral infections.