Large-scale rotating filter perfusion system for high-density growth of mammalian suspension cultures

A system has been developed for growth and maintenance of mammalian cells in suspension culture at high density. In principle, the maintenance of constant levels of required nutrients coupled with the removal of toxic cell byproducts can support much higher suspension cell densities than may be obtained in conventional spinners. The system consisted of 4- or 40-liter reaction vessels equipped with a vertically supported rotating cylindrical filter. Agitation was provided by the magnetically driven, rotating filter. Fresh medium was supplied at a rate of 10 to 20 ml/h per 10(9) cells and the expended medium free of cells was withdrawn through the rotating filter. Both pH and dissolved O2 and CO2 were monitored and regulated. Walker 256 carcinosarcoma cells have been grown in these reactors to densities 10- to 30-fold greater than that obtained in Bellco spinners. In addition to high cell densities, the yield of cells per liter of medium used was 2- to 3-fold that obtained in the conventional systems. Both 4- ad 40-liter reactor also has been operated without the use of antibiotics. The 40-liter reactor also has been modified for chemostat operation. In a single run, for example, the Walker cell density was maintained between 6 and 10 x 10(6) cells/ml with a total yield of 8.7 x 10(11) cells from 360 liters of medium.