Human Dendritic Cells
As sentinels of the immune system, human dendritic cells (DCs) are located in all tissues, especially those at the interface between the external environment and the body, such as lung, intestine, and skin. DCs are divided into plasmacytoid DCs (pDCs) and conventional DCs (cDCs), cDCs are further split into type 1 (cDC1) and type 2 (cDC2). Functionally, cDCs include two states: immature and mature. Immature DCs are professional in uptaking and processing antigens, and mature DCs are specialist in antigen presentation. It has been observed that immature cDCs can induce immune tolerance, while mature cDCs induce Th2 or Th1 immune responses.