Utilization of Storage-protein 2 from Silkworm Hemolymph to Reduce Cell Death in Chinese Hamster Ovary Cell Cultures

초록

Chinese hamster ovary (CHO) cells are used widely for the industrial production of various recombinant therapeutic proteins. It is important to reduce cell death during cell culture for improving protein production. Storage-protein 2 (SP2) is a soluble protein derived from silkworm hemolymph. Molecular weight of SP2 is approximately 70 kDa and amino acid sequence is confirmed. In this study, we investigated the effect of SP2 on the recombinant CHO cells producing albumin-erythropoietin (Alb-EPO). The addition of SP2 increased viable cell density and viability. Also, it was confirmed that the inhibition of aggregation as well as apoptosis was more effective than control. Aggregation rate was decreased by 20% at 2 mg/ml of SP2. When the cells were cultured with 2.0 mg/ml of SP2, viable cells were 1.66-fold higher than that of control culture. In the control condition, percentage of apoptosis was 44.7%, whereas culture with 2.0 mg/ml of SP2 was 11.4%. Productivity of Alb-EPO was increased 1.48-fold compared to that of the control. In conclusion, SP2 was found to be a useful supplement for reducing cell aggregation and it was apparent that the addition of SP2 could enhance the productivity by reducing apoptosis.