Aging of dendritic cells. Aging affects both of the major functions of dendritic cells (DCs); stimulation and amplification of immunity and induction of peripheral tolerance. DCs are responsible for initiating and directing the immune response to antigens and play an integral role in the prevention of autoimmunity and unrestrained inflammation. Aged DCs are unable to efficiently prime and recruit T cells, migrate to peripheral lymph structures or maintain tolerance to self. They become trapped in peripheral tissues, perpetuating the immune response and can cause unresolved smoldering inflammation and subsequent tissue damage.