Recombinant human erythropoietin produced by Namalwa cells.

To establish a practical exogenous gene expression system in human cells, a cDNA coding for human erythropoietin (EPO) was expressed in human B-lymphoblastoid Namalwa cells. The Namalwa-derived recombinant EPO was purified from the culture fluid by a simple three-step procedure. The Namalwa EPO showed an equivalent activity in vivo to that of human urinary EPO. Oligosaccharide structure analyses suggested that almost all N-linked oligosaccharide chains of Namalwa EPO are shared by urinary EPO. The two major N-linked oligosaccharides of Namalwa EPO were fucose-containing tetraantennary and fucose-containing triantennary structures.