The high specificity that is characteristic of a humanized monoclonal antibody makes it an ideal tool for cancer therapies. The ability to successfully reduce the uncertainties around development and to augment the efficacy of the final product is very much dependent on establishing a process that allows reproducibility from development to manufacturing.
During development of an antibody biologic as an anticancer medicine, various activities, such as clone selection, expansion, and verification, often require different medium requirements, calling for multiple media. Transitioning from one medium to another typically poses a certain level of risk in maintaining the clone of interest.
Irvine Scientific developed BalanCD™ CHO Growth A as a chemically defined, high-performance CHO production medium for batch and fed-batch processes. Experiments were designed to evaluate the potential of BalanCD CHO Growth A for both supporting early cell-line development activities and for determining its scalability to larger-scale production.
BalanCD CHO Growth A was evaluated, together with 10% FBS containing DMEM/F12 and one other commercially available CHO cloning medium (Media S), for single-cell subcloning in a limiting dilution assay. Using three monoclonal antibody-expressing CHO lines (CHO-M, CHO-S, and CHO DXB11), cells were seeded in 96-well plates at a calculated 1 cell/well in each test medium.
Plates, incubated at 37°C, 5% CO2 in a humidified incubator, were evaluated on day 14 using light microscopy and scored for colony growth (Figure 1). Cells plated in BalanCD CHO Growth A formed more colonies than the 10% FBS condition for all three cell lines. The average colony size in the BalanCD CHO Growth A condition was comparable to that in the 10% FBS condition (image not shown) and larger than that in the Media S cloning medium. BalanCD CHO Growth A appears to be effective in the single-cell cloning applications.