mDCs

mDCs, or myeloid dendritic cells, are a crucial component of the innate and adaptive immune systems. They are a type of antigen-presenting cell (APC) that plays a vital role in initiating immune responses. Originating from myeloid progenitor cells in the bone marrow, mDCs circulate in the blood and reside in various tissues, including the skin, mucosa, and lymph nodes. Their primary function is to capture, process, and present antigens to lymphocytes, particularly T cells.

Upon encountering pathogens or foreign substances, mDCs mature and migrate to lymphoid organs. During maturation, they upregulate the expression of surface molecules necessary for T cell activation, such as MHC class II and co-stimulatory molecules. Once in the lymph nodes, mDCs present processed antigens on their MHC molecules to naive T cells. This interaction is critical for priming T cells and directing the type of immune response mounted, whether it be cellular or humoral immunity.

mDCs are diverse and can be further categorized into subsets based on their surface marker expression and functional properties, such as conventional dendritic cells (cDCs) and plasmacytoid dendritic cells (pDCs). Conventional DCs are further divided into cDC1 and cDC2 subsets, each with specialized roles in antigen presentation and immune cell recruitment. Their ability to bridge the innate and adaptive immune responses makes mDCs essential for effective defense against infections and for maintaining immune homeostasis.