CONTINUOUS PRODUCTION OF HUMAN ERYTHROPOIETIN BY IMMOBILIZED RECOMBINANT L-929 CELLS

Recombinant L-929 cells transfected with the human erythropoietin (EPO ) gene were immobilized in a macroporous cellulosic support and its de rivatives in which charged groups or cell attachment factors were intr oduced. The immobilized cells were cultured in serum-containing and se rum-free media. Comparable production of EPO was observed even in the serum-free medium when a support modified by polyethyleneimine was use d for immobilization. The cells immobilized on the supports were cultu red in fluidized-bed and inner-loop type air-lift bioreactors for cont inuous production of EPO. A high cell density of more than 2 x 10(7) c ells/cm3-support and high EPO productivity were achieved and maintaine d for 50 d through the use of the inner-loop type air-lift bioreactor. The productivity was 13.4-fold higher than that of conventional stati c cultures in petri-dishes.