CELLS

Dendritic cells (DCs), a class of bone marrow-derived cells found in the blood, tissues, and lymphoid organs, are antigen presenting cells that serve as a conduit between the innate and adaptive immune systems.^1,2 DCs recognize and respond to pathogen-associated molecular patterns capable of initiating an acute inflammatory reaction. Furthermore, they process extracellular and intracellular proteins to present antigens to prime naïve T cells. The three major classes of DCs are pDC, myeloid cDC1, and myeloid cDC2.²

DCs possess a characteristic shape and motility, like no other blood cell, and these features complement their function of capturing antigens and selecting antigen-specific T cells. DCs can stimulate both B and T lymphocytes. Having their presence in most tissues, DCs capture and process antigens and display large amounts of MHC-peptide complexes at their surface. After upregulating their costimulatory molecules and migration to lymphoid organs (spleen and lymph nodes), DCs collaborate and activate antigen-specific T cells.¹ Through their maturation process, DCs also upregulate surface proteins, such as CD80, CD86, and CD40, which are critical for T-cell activation and response and synthesize high levels of IL-12 that enhance both innate and acquired immunity.^1,2

DCs serve as a potential target in many clinical scenarios that involve T cells, such as transplantation, tumors, immunodeficiency, and vaccines.¹ DC dysfunction is known to contribute to the development of infectious diseases, cancer, allergy, and autoimmune disease.^1,2

​​cDC1: type 1 conventional DC; cDC2: type 2 conventional DC; CD: cluster of differentiation; IL: interleukin; MHC: major histocompatibility complex; pDC: plasmacytoid DC.