There are different subsets of DCs, most commonly found in the systemic circulation are:.Dendritic cells are not only important elements of the innate immune system but also constitute the most efficient antigen-presenting cells for T cell activation, thus linking innate and adaptive immune responses.Dendritic cells (DCs) are a sparsely distributed, migratory group of cells that are specialized to sample the sites of entry of infectious agents.Macrophage capacity to kill pathogenic microorganisms also can be overcome by microbes that are able to survive inside cells, establishing an intracellular infection, such as Salmonella spp, Mycobacterium tuberculosis, Cryptococcus neoformans, or Toxoplasma gondii.ĭendritic Cells Produce Inflammatory Cytokines and Initiate Adaptive Immunity by Presenting Antigens to T Cells.Although phagocytosis and cytokine/chemokine production are the two key effector functions of macrophages in the innate immune response, these cells also have a role in adaptive responses as antigen-presenting cells and as targets of the effector components of the cellular and humoral adaptive responses, being activated by T cell-derived cytokines and antibodies.Some important systemic effects of cytokines produced by macrophages are fever induced by IL-1, wasting (i.e., cachexia) caused by TNF-alpha, production of acute phase proteins by liver induced by IL-6, and an increase in the maturation and release of neutrophils from bone marrow by IL-3.The major cytokines produced by macrophages are TNF-alpha, IL-1 beta, IL-6, and IL-8 and IL-33.(5) regulate immunity through the alternatively activated pathway.(4) releasing cytokines and chemokines that play a major role in innate immune responses.(3) processing and presentation of antigens for recognition by T cells, expressing co-stimulatory molecules, mainly during secondary adaptive immune responses.(2) scavenging of worn-out cells, apoptotic bodies, and other debris potentially harmful to tissues.(1) capture by phagocytosis and intracellular killing of microorganisms, infected cells, and tumor cells through PAMP recognition.Macrophages actually have a number of important functions in body defense such as.In contrast to neutrophils, which are end-stage nonreplicating cells continually replaced from the bone marrow, mononuclear phagocytes can proliferate in situ and are long-lived (i.e., months to years).Other names have been applied to tissue macrophages such as Kupffer cells in the liver, histiocytes in connective tissues, mesangial cells in the kidneys, osteoclasts and chondroclasts in bones and cartilage, alveolar macrophages in the lungs, and microglial cells in the brain.When these cells are recruited by chemotactic molecules and leave the circulation, they become activated and differentiate into macrophages.

Monocytes are bone marrow-derived cells and are continuously released into the blood.

Mononuclear phagocytes (monocytes and macrophages) are essential for the development of inflammation and together with neutrophils are the phagocytic cells involved in the clearance of inert particles and microbial agents.Mononuclear Phagocytes Produce Key Inflammatory Cytokines and Chemokines

Imate cell