SCGF-α and -β are hematopoietic growth factor that exerts their activity at early stages of hematopoiesis. The SCGFs are non-glycosylated species-specific cytokines that can support growth of primitive hematopoietic cells, and in combination with EPO or GM-CSF, promote proliferation or erthroid or myeloid progenitors, respectively. Recombinant human SCGF-β is a 25.0 kDa polypeptide containing 227 amino acid residues.