Interleukin 6 (IL-6) is a pro-inflammatory cytokine protein and intricate member of the immune response. Also acts as an anti-inflammatory myokine. Secreted by T cells, macrophages, osteoblasts, and smooth muscle cells for a variety of functions, including stimulating immune response for bacterial infection, burns, trauma, inducing fever, stimulating osteoclast formation, and inducing inflammation. Also inhibits TNF-alpha and IL-1 and activates IL-1ra and IL-10, leading to anti-inflammatory activity. Agonist of the IL-6 receptor, and implicated in multiple inflammatory diseases, including systemic juvenile rheumatoid arthritis and diabetes mellitus susceptibility.