Figure 4 Comparison of the effect of temperature downshift between shake flask and bioreactor fed-batch cultures of HP CHO cells. (●, black) constant temperature culture in shake flask, (▲, green) temperature downshift culture in shake flasks, (■, pink) constant temperature culture in the bioreactor, and (▼, purple) temperature downshift culture in the bioreactor. The temperature was downshifted from 37°C to 33°C on day 5 (vertical dashed line). (a) Viable cell density. (b) Cell viability. (c) antibody titer. (d) antibody-specific production rate. (e) Significance analysis of final antibody titer. (f) Significance analysis of the rate of antibody-specific. Samples were taken at 24-h intervals and experimental values represent three biological replicates ± SD. Two-tailed Student’s t-test was conducted using GraphPad Prism 8.0 ((*) p < 0.05, (**) p < 0.01, (***) p < 0.001 and (****) p < 0.0001).