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-α is a 33.9 kDa polypeptide containing 305 amino acid residues.