Preliminary evaluation of microcarrier culture for growth and monoclonal antibody production of CHO-K1 cells

Large-scale biopharmaceutical production commonly relies on suspension cell cultures that provide higher yields than adherent cultures. However, most mammalian cells grow adherently and therefore need to be adapted to suspended growth, which is not always simple or feasible. Microcarrier culture introduces new possibilities and makes achievable the practical high yield culture of anchorage-dependent cells in suspension systems. The aim of this study was to evaluate and optimize the use of microcarrier culture for the growth and antibody production of CHO-K1 cells. For this, the macroporous Cultispher microcarriers were used, and the initial cell adhesion to the microcarriers (occurring in the first 5-6 hours) and further cell proliferation were assessed. Cultures of antibody-producing CHO-K1 cells were performed in 50 ml vented conical tubes, and different conditions were tested: initial cell concentration (2x105 cells/ml and 4x105 cells/ml), microcarrier concentration (1 g/L and 2 g/L), type of rocking during the first 6 hours of adhesion (pulse or continuous) and rocking after initial adhesion (no rocking and 60 rpm). Cell concentration and viability in the microcarriers were assessed periodically (hourly for the adhesion phase, and daily after that). It was observed that an increase in the initial cell concentration does not enhance initial adhesion, possibly due to saturation of the microcarrier surface. For its turn, increasing microcarrier concentration, without further increasing initial cell concentration does not improve cell densities achieved in the culture. Concerning rocking, the most favorable type for the adhesion phase was pulse rocking and, after this, a continuous rocking provided an improved cell proliferation. In conclusion, microcarrier cultures proved to be a viable alternative to suspended cultures for the growth and antibody production of CHO-K1 cells