초록
In an effort to improve TNFR-Fc production in GS-CHO cells, batch cultures were performed to investigate the effects of low culture temperature on TNFR-Fc production. It was observed that low culture temperatures resulted in cell cycle arrest in the G1 phase, led to suppressed cell growth, and prolonged the culture period. Although the highest TNFR-Fc concentration was achieved with a culture temperature of <TEX>$32^{\circ}C$</TEX> at 247.4 mg/L, the maximum <TEX>$q_{TNFR-Fc}$</TEX> of 15.7 pg/cells/day was achieved at <TEX>$30^{\circ}C$</TEX>. Because the inhibition effect on cell growth at <TEX>$30^{\circ}C$</TEX> compromised its beneficial effects specifically to TNFR-Fc productivity, TNFR-Fc concentration at this temperature was not significantly increased. Furthermore, the increase in productivity of specific TNFR-Fc at low culture temperatures was also found to be due to an increase in the transcriptional level of the <TEX>$TNFR-Fc$</TEX> gene, determined by RT-PCR analysis. In addition, low culture temperatures had no significant effect on the degree of sialylation of TNFR-Fc. Taken together; a biphasic cultivation process developed in a fed-batch mode with a low temperature-production phase enhanced TNFR-Fc production by GS-CHO cells and therefore offers major potential for bioprocess optimization.