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Cytokines (Greek:Cyto from Greek "κύτταρο" ''kyttaro'' "cell" + Kines from Greek "κίνηση" ''kinisi'' "movement") are a broad and loose category of small proteins (~5–20 kDa) that are important in cell signaling. They are released by cells and affect the behavior of other cells. Cytokines can also be involved in autocrine signaling. Cytokines include chemokines, interferons, interleukins, lymphokines, tumour necrosis factor but generally not hormones or growth factors (despite some terminologic overlap). Cytokines are produced by a broad range of cells, including immune cells like macrophages, B lymphocytes, T lymphocytes and mast cells, as well as endothelial cells, fibroblasts, and various stromal cells; a given cytokine may be produced by more than one type of cell.〔"Cytokine" in John Lackie. A Dictionary of Biomedicine. Oxford University Press. 2010. ISBN 9780199549351〕〔"Cytokine" in Stedman’s Medical Dictionary, 28th ed. Wolters Kluwer Health, Lippincott, Williams & Wilkins (2006)〕〔Horst Ibelgaufts. (Cytokines ) in Cytokines & Cells Online Pathfinder Encyclopedia Version 31.4 (Spring/Summer 2013 Edition)〕 They act through receptors, and are especially important in the immune system; cytokines modulate the balance between humoral and cell-based immune responses, and they regulate the maturation, growth, and responsiveness of particular cell populations. Some cytokines enhance or inhibit the action of other cytokines in complex ways.〔 They are different from hormones, which are also important cell signaling molecules, in that hormones circulate in much lower concentrations and hormones tend to be made by specific kinds of cells. They are important in health and disease, specifically in host responses to infection, immune responses, inflammation, trauma, sepsis, cancer, and reproduction. == Discovery of cytokines == Interferon-alpha, an interferon type I, was identified in 1957 as a protein that interfered with viral replication.〔Alexander G. Izaguirre. (Molecular Mediators, Cytokines I: Lecture I: Topic I: Cytokines )〕 The activity of interferon-gamma (the sole member of the interferon type II class) was described in 1965; this was the first identified lymphocyte-derived mediator.〔 Macrophage migration inhibitory factor (MIF) was identified simultaneously in 1966 by John David and Barry Bloom.〔 In 1969 Dudley Dumonde proposed the term "lymphokine" to describe proteins secreted from lymphocytes and later, proteins derived from macrophages and monocytes in culture were called "monokines". As scientists learned more, it was understood that these proteins and others were part of a broader class of proteins involved in self-defense, and should be called "cytokines".〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「cytokine」の詳細全文を読む スポンサード リンク
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