Description
Human Interleukin 15 (IL-15) is produced primarily by epithelial cells, fibroblasts and monocytes, but its mRNA is found in a wide variety of human cell types including peripheral blood mononuclear cells, placenta, skeletal muscle, kidney, lung, liver, heart and bone marrow stromal cells. IL-15 shares many biological properties with IL-2 including T, B, and NK cell stimulatory activities. In contrast, they have opposing activities on specific subpopulations, IL-15 promotes division of CD8 memory T cells whereas IL-2 inhibits such division. Human IL-15 cDNA encodes a 162 amino acid residue precursor protein containing a 48 amino acid residue signal peptide that is cleaved to yield the 114 amino acid residue mature protein. IL-15 binds to a heterotrimeric receptor formed by IL-15Ra and the IL-2Rb and g chains. Human IL-15 is active in mouse cells