Temperature shift in CHO Cultures: Effect on Productivity and Product Quality

What is it about?

We have demonstrated that temperature reduction from 37 to 33 °C in the culture of a CHO cell line producing recombinant human granulocyte macrophage colony stimulating factor (CHO-K1-hGM-CSF) leads to a reduced growth rate, increased cell viability, improved cellular productivity, and decreased cell metabolism. In the present study,CHO-K1-hGM-CSFcells were cultured in a biphasic mode: first,a37°C growth phase for achieving a high cell number, followed by a production phase where the culture temperature was shifted to 33 °C. The maximum cell density was not affected after temperature reduction while cell viability remained above 80% for a further 3.7 days in the culture kept at the lower temperature, when compared to the control culture maintained at 37 °C. Furthermore, the total rhGM-CSF production increased 6 times in the culture shifted to 33 °C. Because the quality and hence the in vivo efficacy of a recombinant protein might be affected by numerous factors, we have analyzed the N-andO-glycosylation of the protein produced under both cell culture conditions using high-pH anion-exchange chromatography and complementary mass spectrometry techniques. The product quality data obtained from the purified protein preparations indicated that decreasing temperature had no significant effect on the rhGM-CSF glycosylation profiles, including the degree of terminal sialylation. Moreover, both preparations exhibited the same specific in vitro biological activity.

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Why is it important?

Our results revealed that the employed strategy (temperature reduction in CHO cultutres) had a positive effect on the cell specific productivity of CHO-K1-hGM-CSF cells without affecting product quality, representing a novel procedure for the rhGM-CSF production process.

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