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)
- InterLeukin-3 (IL-3)
- 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)
- InterLeukin-8 (IL-8)
- 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)
- InterLeukin-13 (IL-13)
- Interleukin-15 (IL-15)
- InterLeukin-17 (IL-17)
- 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.