Figure 4. The figure shown here is the average protein concentration of triplicate samples in g/L. Control and runs 179 and
258 were compared when culture viability dropped below 50%. The error bars indicate ±1 standard deviation.
Viable cell density for run 258 was maximal on day 7, with greater than 7 x 106/mL, and dropped to 5 x 106/mL on day 9. Run 179 had the highest viable cell density, reaching 8 x 106/mL on day 6 before dropping to 2 x 106/mL by day 9. The average protein productivity of the cells with two different feed combinations performed in shake flasks
is shown in Figures 4 and 5. Figure 4 shows the average protein concentration at the time of harvest, and Figure 5 shows the
daily cumulative average protein concentration. At viable cell densities correlating with cell harvest conditions, the average
protein concentration was 0.3 g/L for the control, 0.9 g/L for run 258, and 1.2 g/L for run 179. The protein productivity
of samples 258 and 179 was three to four times greater than the control.
Figure 5. Cumulative average protein productivity of the triplicate control samples and the 179 and 258 run triplicate samples
on day 3, day 5, day 6, day 8, and day 9.
Growth of CHO cell cultures in a shaker plate model system was shown to be comparable to growth in shake flasks. This model
system enabled the use of automated liquid handling and plate-based assay techniques to be combined with design of experiments
to create a high-throughput platform for medium and feed development. To develop an optimized feed formulation, 100 cell culture
medium components were screened and tested in 16-factor central composite design experiments. The results of the top two feed
formulations were confirmed in shake flasks to increase productivity three to four times, up to 1.2 g/L. Each experiment took
one day to set up and up to nine days to execute; thus, a media development program of this scope can be conducted by one
researcher in approximately one month.
KANVASRI JONNALAGADDA is a senior research associate at Xcellerex, Inc., Marlborough, MA, 508.480.9235, email@example.com MONICA PICARELLA is a senior research associate, AMANDA HOLMGREN is a research associate, KEITH KROPP is an associate director, and GEOFF HODGE is vice president of process development and technology, all at Xcellerex Inc., Marlborough, MA.