Interleukins are a group of cytokines (secreted proteins/signaling molecules) that were first seen to be expressed by white blood cells (leukocytes), The term interleukine, (inter-) as a means of communication, (-leukin) deriving from the fact that many of these proteins are produced by leukocytes and act on leukocytes. The name is something of a relic though (the term was coined by Dr. Paetkau, University of Victoria); it has since been found that interleukins are produced by a wide variety of body cells. The function of the immune system depends in a large part on interleukins, and rare deficiencies of a number of them have been described, all featuring autoimmune diseases or immune deficiency. The majority of interleukins are synthesized by helper CD4+ T lymphocytes, as well as through monocytes, macrophages, and endothelial cells. They promote the development and differentiation of T, B, and hematopoietic cells. A list of interleukins: | Name | Source [1] | Target receptors[1][2] | Target cells[1] | Function[1] | | IL-1 | macrophages, B cells, monocytes [3], dendritic cells [3] | CD121a/IL1R1, CD121b/IL1R2 | T helper cells | co-stimulation [3] | | B cells | maturation & proliferation [3] | | Nk cells | activation[3] | | macrophages, endothelium, other | inflammation[3], small amounts induce acute phase reaction, large amounts induce fever | | IL-2 | TH1-cells | CD25/IL2RA, CD122/IL2RB, CD132/IL2RG | activated[3] T cells and B cells, NK cells, macrophages, oligodendrocytes | stimulates growth and differentiation of T cell response. Can be used in immunotherapy to treat cancer or suppressed for transplant patients. | | IL-3 | activated T helper cells[3], mast cells, NK cells, endothelium, eosinophils | CD123/IL3RA, CD131/IL3RB | hematopoietic stem cells | differentiation and proliferation of myeloid progenitor cells [3] to e.g. erythrocytes, granulocytes | | mast cells | growth and histamine release[3] | | IL-4 | TH2-cells, just activated naive CD4+ cell, memory CD4+ cells, mast cells, macrophages | CD124/IL4R, CD132/IL2RG | activated B cells | proliferation and differentiation, IgG1 and IgE synthesis[3]. Important role in allergic response (IgE) | | T cells | proliferation[3] | | endothelium | | | IL-5 | TH2-cells, mast cells, eosinophils | CD125/IL5RA, CD131/IL3RB | eosinophils | production | | B cells | differentiation, IgA production | | IL-6 | macrophages, TH2-cells, B cells, astrocytes, endothelium | CD126/IL6RA, CD130/IR6RB | activated B cells | differentiation into plasma cells | | plasma cells | antibody secretion | | hematopoietic stem cells | differentiation | | T cells, others | induces acute phase reaction, hematopoiesis, differentiation, inflammation | | IL-7 | bone marrow stromal cells and thymus stromal cells | CD127/IL7RA, CD132/IL2RG | pre/pro-B cell, pre/pro-T cell, NK cells | differentiation and proliferation of lymphoid progenitor cells, involved in B, T, and NK cell survival, development, and homeostasis, ↑proinflammatory cytokines | | IL-8 | macrophages, lymphocytes, epithelial cells, endothelial cells | CXCR1/IL8RA, CXCR2/IL8RB/CD128 | neutrophils, basophils, lymphocytes | Neutrophil chemotaxis | | IL-9 | Th2-cells, specifically by CD4+ helper cells | CD129/IL9R | T cells, B cells | Potentiates IgM, IgG, IgE, stimulates mast cells | | IL-10 | monocytes, TH2-cells, CD8+ T cells, mast cells, macrophages, B cell subset | CD210/IL10RA, CDW210B/IL10RB | macrophages | cytokine production[3] | | B cells | activation [3] | | mast cells | | | Th1 cells | inhibits Th1 cytokine production (IFN-γ, TNF-β, IL-2) | | Th2 cells | Stimulation | | IL-11 | bone marrow stroma | IL11RA | bone marrow stroma | acute phase protein production, osteoclast formation | | IL-12 | dendritic cells, B cells, T cells, macrophages | CD212/IL12RB1, IR12RB2 | activated [3] T cells, | differentiation into Cytotoxic T cells with IL-2[3], ↑ IFN-γ, TNF-α, ↓ IL-10 | | NK cells | ↑ IFN-γ, TNF-α | | IL-13 | activated TH2-cells, mast cells, NK cells | IL13R | TH2-cells, B cells, macrophages | Stimulates growth and differentiation of B-Cells (IgE), inhibits TH1-cells and the production of macrophage inflammatory cytokines (e.g. IL-1, IL-6), ↓ IL-8, IL-10, IL-12 | | IL-14 | T cells and certain malignant B cells | | activated B cells | controls the growth and proliferation of B cells, inhibits Ig secretion | | IL-15 | mononuclear phagocytes (and some other cells), especially macrophages following infection by virus(es) | IL15RA | T cells, activated B cells | Induces production of Natural Killer Cells | | IL-16 | lymphocytes, epithelial cells, eosinophils, CD8+ T cells | CD4 | CD4+ T cells (Th-cells) | CD4+ chemoattractant | | IL-17 | T helper 17 cells (Th17) | CDw217/IL17RA, IL17RB | epithelium, endothelium, other | osteoclastogenesis, angiogenesis, ↑ inflammatory cytokines | | IL-18 | macrophages | CDw218a/IL18R1 | Th1 cells, NK cells | Induces production of IFNγ, ↑ NK cell activity | | IL-19 | - | IL20R | | - | | IL-20 | - | IL20R | | regulates proliferation and differentiation of keratinocytes | | IL-21 | activated T helper cells, NKT cells | IL21R | All lymphocytes, dendritic cells | costimulates activation and proliferation of CD8+ T cells, augment NK cytotoxicity, augments CD40-driven B cell proliferation, differentiation and isotype switching, promotes differentiation of Th17 cells | | IL-22 | - | IL22R | | Activates STAT1 and STAT3 and increases production of acute phase proteins such as serum amyloid A, Alpha 1-antichymotrypsin and haptoglobin in hepatoma cell lines | | IL-23 | - | IL23R | | Increases angiogenesis but reduces CD8 T-cell infiltration | | IL-24 | - | IL20R | | Plays important roles in tumor suppression, wound healing and psoriasis by influencing cell survival. | | IL-25 | - | LY6E | | Induces the production IL-4, IL-5 and IL-13, which stimulate eosinophil expansion | | IL-26 | - | IL20R1 | | Enhances secretion of IL-10 and IL-8 and cell surface expression of CD54 on epithelial cells | | IL-27 | - | IL27RA | | Regulates the activity of B lymphocyte and T lymphocytes | | IL-28 | - | IL28R | | Plays a role in immune defense against viruses | | IL-29 | - | | | Plays a role in host defenses against microbes | | IL-30 | - | | | Forms one chain of IL-27 | | IL-31 | - | IL31RA | | May play a role in inflammation of the skin | | IL-32 | - | | | Induces monocytes and macrophages to secrete TNF-α, IL-8 and CXCL2 | | IL-33 | - | | | Induces helper T cells to produce type 2 cytokine | | IL-35 | regulatory T cells | | | Suppression of T helper cell activation | [edit] References [edit] External links | Cell signaling: cytokines | | | By family | | Interleukin | | IL-1 superfamily | | | | | | | | IL-10 family | | | | | | | | | | | | IL-12 family | | | | Other | | | | | | | | | | | Main | | | | TNF (ligand) superfamily | | | | | | | | | | | | | | Other | | | | By function | | | |