Scanning Electron Micrograph (SEM) showing an immature dendritic cell. Dendritic cells (DCs) are antigen-presenting cells (accessory cells) of the mammalian immune system. Their main function is to process antigen material and present it on the cell surface to the T cells of the immune system. They act as messengers between the innate and the adaptive immune systems. Dendritic cells are present in those tissues that are in contact with the external environment, such as the skin and the inner lining of the nose, lungs, stomach and intestines. They can also be found in an immature state in the blood. Once activated, they migrate to the lymph nodes where they interact with T cells and B cells to initiate and shape the adaptive immune response. Immature dendritic cells are also called veiled cells, as they possess large cytoplasmic veils rather than dendrites. Magnification unknown.