Dendritic Cells: Functional Consideration, Immunological Role, Clinical Applications and Environmental Influence

Dendritic cells are the most effective and profesional antigen-presenting cells (APCs) that initiate primary immune response. They not only activate lymphocyte to induce immune responses but also minimize autoimmune reactions by tolerizing T cells to self antigens. They are highly specialized for antigen uptake and processing. DCs show branched cytoplasmic projections, the dendrites.The life cycle of DCs has been outlined by three stages of maturation: precursor, immature and mature DCs. Each stage has characteristic features, specific function and special anatomical site. They are migratory cells that traffic from one site to the next, performing specific function at each site. There are many DCs classification according to: their origin, being in vivo or vitro and finally according to their distribution in the body.The function of DCs starts by antigen capturing followed by migration to lymph tissues and finally antigen presentation and T cell activation. In recent years, DCs have been increasingly studied for their role as critical adjuvants in vaccines for prevention of microbial infection and allograft rejection and treatment of cancer and autoimmune diseases.Many methods are developed for detection of DCs. Due to their critical role in cancer, induction of DC apoptosis may be one of the central mechanisms used by tumors to evade immune recognition.External or internal environmental factors may affect DCs.