Human flt3-Ligand (flk2-ligand) stimulates the proliferation and colony formation of certain bone marrow precursor cells including CD34+ cells. The antibody was produced using the recombinant human flt3-ligand as immunogen, which is a soluble 17.6 kDa polypeptide containing 155 amino acid residues, that comprises the extracellular domain of the transmembrane flt3-ligand protein.