Interleukin-6, as known as IL-6, is an immunoregulatory lymphokine produced by T-cells in response to antigenic or mitogenic stimulation. It is also a "myokine," a cytokine produced from muscle, and is elevated in response to muscle contraction. IL-6 acts as both a pro-inflammatory and anti-inflammatory cytokine. Smooth muscle cells in the tunica media of many blood vessels also produce IL-6. It is mediated through its inhibitory effects on TNF-alpha and IL-1, and activation of IL-1ra and IL-10.