Production of monoclonal antibody using free and immobilized hybridoma cells.

Abstract

Monoclonal antibody (MAb) production using immobilized hybridoma cells and free cells were compared with respect to shear sensitivity, efficiency of serum utilization for MAb production, and stability of MAb productivity. First, shear sensitivity of free cells was studied with respect to growth phase and media type. Cells in stationary and decline phases were more sensitive to shear than cells in the growth phase. Since a significant portion of MAb is produced during both the stationary and decline phase, it is important to protect cells from shear in order to maintain cell viability during these phases. Cells in low serum and serum-free media were more sensitive to shear than cells in high serum medium. The problem of shear sensitivity of cells in stationary phase and serum-free media could be overcome by immobilization of the cells. Second, it was evaluated whether immobilized cells can utilize serum more efficiently for MAb production than free cells. In free cell culture, serum influenced cell growth, but not specific MAb productivity. In immobilized cell culture, cell density was maintained at about 1.8 $\cdot$ 10$\sp6$ cell/ml of medium despite the reduction of serum concentration from 10% to 1%. Serum did not influence the specific MAb productivity of either immobilized cells or free cells. However, specific MAb productivity of immobilized cells was about three times higher than that of free cells. Due to both high cell density and the enhanced specific MAb productivity, immobilized cells utilized serum more efficiently for MAb production than free cells. Third, it was evaluated whether stability of MAb production can be improved by immobilization. Free cells in serum-free media showed a decrease in MAb productivity in long-term cultivation. This loss of MAb productivity was not observed when the cells were immobilized in alginate beads. A mathematical model for a balance between MAb producing and non-producing populations indicates that the improvement in stability of MAb production by immobilization may be related to either limited generations of cells or reduced mutation rate. These observations show that immobilized cell culture is more efficient than free cell culture for MAb production.