Factors affecting monoclonal antibody production in culture.

Factors that affect production of monoclonal antibodies (McAb) by a murine cell line were investigated. The goal was to estimate the efficiency of large scale production in stirred reactors. It was found that in batch cultures most McAb was produced after the log growth phase; final yield was 100-200 micrograms/ml. Yields of McAb were increased to 290 micrograms/ml by feeding cells glucose and glutamine. Lactic acid, which was produced in culture as a result of glucose metabolism, had no toxic effect on cells, while another waste product, ammonium ion, was probably accumulated at toxic levels during late stages of cell growth. The hybridoma cell line was propagated in four different systems: fed-batch, semi-continuous, two stage and perfusion. These systems were compared to batch cultures for their effect on cell viability and antibody production. Daily addition of fresh medium (fed-batch propagation) increased antibody productivity from 15 (batch culture) to 27 mg/l of culture/day. In the semi-continuous culture productivity was raised to 34 mg/l/day. Further increase in productivity to a level of 62 mg/l/day was achieved by applying a second batch stage to the semi-continuous culture. A perfusion culturing method was the most effective for production of McAb. Average concentrations of 2.2 X 10(7) live cells/ml and 390 micrograms of antibody/ml corresponding to productivity of 660 mg/l/day were achieved. Serum concentration in the medium was reduced to 0.125% resulting in a specific activity of 0.4 mg of McAb per mg of protein in the cell-free culture broth.