Interleukin 2 (IL-2) was initially identified as a T cell growth factor that is produced by T cells following activation by mitogens or antigens. Since then, it has also been shown to stimulate the growth and differentiation of B cells, natural killer (NK) cells, lymphocyte activated killer (LAK) cells, monocytes/macrophages and oligodendrocytes. At the amino acid sequence level, there is approximately 60-90% similarity between species. Mature human IL-2 shares 60%, 72%, 72%, 78%, and 86% similarities with mouse, equine, porcine, feline, and canine, respectively.
Image: IL-2 producing staining of lymphocytes in human peripheral blood mononuclear cell (PBMNC) cultures after PMA and ionomycin stimulation. Cells were stained using anti-mouse Texas Red (red) and counterstained with Fluoro Nissl Green.