|-
| align="center" colspan="2" |
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| colspan="2" bgcolor="#dddddd" | Identifiers
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| bgcolor="#e7dcc3" | Symbol(s)
| bgcolor="#eeeeee" | [IL6] IFNB2
|-
| bgcolor="#e7dcc3" | Entrez
| bgcolor="#eeeeee" | [3569]
|- class="hiddenStructure"
| bgcolor="#e7dcc3" | OMIM
| bgcolor="#eeeeee" | [147620]
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| bgcolor="#e7dcc3" | RefSeq
| bgcolor="#eeeeee" | [NM_000600]
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| bgcolor="#e7dcc3" | UniProt
| bgcolor="#eeeeee" | [P05231]
|- class="hiddenStructure"
| bgcolor="#e7dcc3" | PDB
| bgcolor="#eeeeee" | []
|-
| colspan="2" bgcolor="#dddddd" | Other data
|- class="hiddenStructure"
| bgcolor="#e7dcc3" | EC number
| bgcolor="#eeeeee" | []
|-
| bgcolor="#e7dcc3" | Locus
| bgcolor="#eeeeee" | Chr. 7[p21-p15]
|-
|}
Interleukin-6 (IL-6) is a pro-inflammatory cytokine secreted by T cells and macrophages to stimulate immune response to trauma, especially burns or other tissue damage leading to inflammation. Additionally osteoblasts to stimulate osteoclast formation. Inhibitors of IL-6 (including estrogen) are used to treat postmenopausal osteoporosis. IL-6 is one of the most important mediators of fever and of the acute phase response. In the muscle and fatty tissue IL-6 stimulates energy mobilization which leads to increased body temperature. IL-6 can be secreted by macrophages in response to pathogen associated molecular patterns (PAMPs) binding the Toll-like Receptor (TLR) present on an active macrophage.
IL-6 is also a "myokine," a cytokine produced from muscle, and is elevated in response to muscle contraction.
IL-6 signals through a cell-surface receptor complex consisting of the ligand-binding IL-6R α chain (CD126), and the signal-transducing component gp130 (CD130). CD130 is the common signal transducer for several cytokines including leukemia inhibitory factor, ciliary neurotropic factor, oncostatin M, IL-11 and cardiotropin-1, and is almost ubiquitously expressed in most tissues. In contrast, the expression of the IL-6R is restricted to certain tissues. IL-6 triggers the formation of protein complexes of gp130 and the IL-6 receptor activating the receptor. These complexes bring together the intracellular regions of gp130 and initiates the signal transduction cascade through Janus kinases (JAKs) and Signal Transducers and Activators of transcription (STATs).
IL-6 is probably the best studied of the cytokines that use gp130 in their signalling complexes. Other cytokines that signal through receptors containing gp130 are Interleukin-11 (IL-11), ciliary neurotrophic factor (CNTF), cardiotrophin-1 (CT-1), cardiotrophin-like cytokine (CLC), leukemia inhibitory factor (LIF), oncostatin M (OSM), Kaposi's sarcoma associated herpes virus interleukin 6 like protein (KSHV-IL6). These cytokines are commonly referred to as the IL-6 like or gp130 utilising cytokines.
In addition to the membrane-bound receptor, a soluble form of IL-6R ( sIL-6R) has been purified from human serum and urine. Many neuronal cells are unresponsive to stimulation by IL-6 alone, but differentiation and survival of neuronal cells can be mediated through the action of sIL-6R. The sIL-6R/IL-6 complex can stimulate neurites outgrowth promote survival of neurons, hence may be important in nerve regeneration through remyelination.
