Purification and characterization of a human erythrocyte-derived growth factor with a wide target cell spectrum

A cell extract from human erythrocytes promoted the growth of a wide variety of cell types, namely human and mouse myeloid cells, human and mouse T cells, human B cells, human melanoma cells, mouse transformed fibroblast cells, mouse mastocytoma cells, human lung fibroblast cells, and mouse bone marrow fibroblast/stroma-like cells. The growth-promoting activity was acid- and heat-labile and sensitive to proteases, indicating the proteinaceous nature of the molecule. The activity was also lost upon exposure to 2-mercaptoethanol. The novel growth-promoting factor, termed basic growth factor because of its fundamental effect and a wide target cell spectrum, was purified by sequential anion-exchange, hydrophobic, gel filtration, hydroxylapatite, and reverse-phase high performance liquid chromatographies. The purified factor has an apparent molecular mass of 53 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing and nonreducing conditions. The factor migrated at 270 kDa on native gradient polyacrylamide gel electrophoresis. Therefore, the factor consists of a homopolymer of a single polypeptide chain. The purified factor promoted the growth of the same cell types as the cell extract, except for bone marrow cells.