Transferrin recycling perfusion culture of hybridoma cells

A perfusion culture of hybridoma cells in serum-free medium recycling transferrin was carried out, which greatly reduced the level of transferrin that was needed. The culture was maintained even without supplying transferrin for nine days. IgG concentration reached 1.1 mg ml−1 in a month of recycling and its ratio to the total protein was 45.8%. The affinity of the antibody did not decrease and no degradation was observed after long recycling period. The cell density under recycling condition was 2≈3 times higher than that without recycling. It was indicated that there was autocrine growth promoting activity in the culture supernatant.