Purity >95% by SDS-PAGE and HPLC, MW: 15.2 kDa (SDS-PAGE). Interleukin-3 (IL-3) is a pleiotropic cytokine belonging to the interleukin family. IL-3 shares similarities with Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) and IL-5: they all have a four-helix bundle structure, are located on the same chromosomes in both human and mouse, are produced by activated T cells, and share receptors. The IL-3/IL-5/GM-CSF receptor family members are all heterodimeric, composed of a receptor-specific a chain and a common Beta chain. IL-3 is also called multi-colony stimulating factor since it stimulates the development and colony formation of multiple lineages of hematopoietic cells by activating intracellular pathways such as Ras-Raf-ERK and JAK/STAT. IL-3 inhibits apoptosis and promotes cell survival by targeting the anti-apoptotic bcl-2 gene family. Recombinant human Interleukin-3 (rhIL-3) produced in E. coli is a single non-glycosylated polypeptide chain containing of 134 amino acids. A fully biologically active molecule, rhIL-3 has a molecular mass of 15.2 kDa analyzed by non-reducing SDS-PAGE and is obtained by chromatographic techniques.