The MP5-20F3 monoclonal antibody reacts with mouse IL-6 (interleukin-6) a 21-28 kDa cytokine that is expressed by many cell types, including T lymphocytes, B lymphocytes, monocytes, fibroblasts, and endothelial cells. IL-6 signals through a cell-surface type I cytokine receptor complex consisting of the ligand-binding IL-6Rα chain (CD126), and the signal-transducing component gp130 (also called CD130). Upon receptor binding IL-6 influences antigen-specific immune responses, inflammatory responses, neuronal development, and is a major mediator of the acute phase reaction. The MP5-20F3 monoclonal antibody has been shown to neutralize the bioactivity of natural or recombinant IL-6.