InterLeukins (IL-#)

A large group of Cytokines (IL-1 to IL-35) produced mainly by Leukocytes, although some are made by PolyMorphoNuclear Phagocytes, or by Auxiliary Cells. They have a variety of functions, but most are involved in directing other Immune Cells to divide and differentiate. Each IL acts on a specific, limited group of cells that express the correct Receptor for that InterLeukin. InterLeukin-1 (IL-1) Produced by activated Macrophages, Endothelia Cells, B-Cells, and Fibroblast Cells. IL-1 induces Inflammatory responses, Edema, promotes the production of ProstaGlandins, IL-2, the growth of Leukocytes, and induce the Acute Phase Reaction. IL-1 also augments CorticoSteroid release, induces fever and shivering - useful responses, because elevated body temperature reduces Bacterial growth. InterLeukin-2 (IL-2) Also known as T-Cell Growth Factor (TGF), it is secreted by stimulated Helper T-Cells (CD4+), CytoToxic T-Cells (CD8+), and Large Granular Lymphocytes (LGL). IL-2 promotes proliferation (Colonal Expansion) and differentiation of additional CD4+ Cells, B-Cells, and activates Macrophages and Oligodendrocytes. InterLeukin-3 (IL-3) Produced by activated T-Cells, it stimulates the proliferation of Precursors in all HematoPoietic Cells (Red Cells, Granulocytes, Macrophages, and Lymphocytes). InterLeukin-4 (IL-4) Stimulates production of AntiBody-producing B-Cells, leading to the production of IgG & IgE. IL-4 also promotes CD8+ Cell growth and promotes Th2 Cell differention. On Macrophages, IL-4 induces MHC Class II expression, but inhibits production of the ProInflammatory Cytokins (IL-1 and Tumor Necrosis Factor-alpha [TNF-]). InterLeukin-5 (IL-5) Is chiefly a growth and activation factor for Eosinophil Cells (a subset of Neutrophils). InterLeukin-6 (IL-6) Is produced by many cell types, including T-Cells, Macrophages, B-Cells, Fibroblasts, and Endothelia Cells. IL-6 stimulates several types of Leukocytes, and the production of Acute Phase Proteins in the Liver. IL-6 is particularly important in inducing B-Cells to differentiate into AntiBody Forming Cells (Plasma Cells). InterLeukin-7 (IL-7) Is made by Bone Marrow Stroma Cells and acts on Thymocytes. IL-7 is a T-Cell growth and activation factor, and a Macrophage Activation Factor. InterLeukin-8 (IL-8) Is produced by most cells of the body, especially Macrophages and Endothelia Cells. IL-8 enhances Inflammation, by enabling Immune Cells to migrate into tissue, and is a powerful inducer of Chemotaxis for Neutrophil Cells. InterLeukin-9 (IL-9) Up-regulates Th1 responses (Enhancing Inflammation) by inhibiting T-Cell Apoptosis. InterLeukin-10 (IL-10) Down-regulates AntiViral Responses by inhibiting: the production of Interferon-gamma (IFN-), Antigen Presentation, and Macrophage production of IL-1, IL-6, and TNF-. IL-10 is also very important in B-Cell activation. InterLeukin-12 (IL-12) Acts in a contrasting manner to IL-10; it promotes Th1 Type Response in Macrophages, NK Cells, and induces IFN- production. InterLeukin-13 (IL-13) Has structural and functional similarities to IL-4 and promotes B-Cell differentiation, inhibits Th1 Cells and the production of Macrophage Inflamatory Cytokines. Interleukin-15 (IL-15) Shares several biological activities with IL-2 and is produced by both Epithelial Cells and Monocytes. IL-15 also induces T-Cell proliferation, enhances NK Cell CytoToxicity and stimulates B-Cells to proliferate and secrete ImmunoGlobulins. InterLeukin-17 (IL-17) Induces production of inflammatory Cytokines. InterLeukin-18 (IL-18) Induces Interferon-gamma (IFN-) production. #30 InterLeukin-23 (IL-23) One of the essential factors required for the expansion of pathogenic CD4+ T-Cells, which is characterized by the production of IL-17, IL-6, and Tumor Necrosis Factor.