title: Adaptation of Chinese hamster ovary cells to low culture temperature: cell growth and recombinant protein production.
abstract: Recombinant Chinese hamster ovary (rCHO) cells producing erythropoietin (EPO) and rCHO cells producing follicle-stimulating hormone (FSH) showed a significant increase in specific productivity (q) when grown at 32 degrees C compared to 37 degrees C. However, low culture temperature suppressed cell growth, and therefore, did not increase volumetric productivity as much as q. In an attempt to increase the volumetric productivity through improvement of hypothermic growth, EPO producing rCHO (CHO-EPO) cells and FSH producing rCHO (CHO-FSH) cells were adapted at 32 degrees C in a repeated batch mode using spinner flasks. Cell growth of both CHO-EPO and CHO-FSH gradually improved during adaptation at 32 degrees C. Specific growth rates of CHO-EPO and CHO-FSH cells at 32 degrees C, through adaptation, were increased by 73% and 20%, respectively. During adaptation at 32 degrees C, mRNA levels of cold-inducible RNA-binding protein (CIRP) of both rCHO cell lines did not change significantly, suggesting that CIRP expression may not be the only cause for growth suppression at low culture temperature. Unlike cell growth, the recombinant protein production of both rCHO cell lines was not increased during adaptation due to decreased specific productivities. The specific EPO productivity and specific FSH productivity were decreased by 49% and 22%, respectively. Southern blot analyses showed that the decreased specific productivities were not due to the loss of foreign gene copies. Taken together, improvement of hypothermic cell growth by adaptation does not appear to be applicable for enhanced recombinant protein production, since specific productivity decreases during adaptation to the low culture temperature.
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 371-1 Kusong-Dong, Yusong-Gu, Daejon 305-701, Republic of Korea.
authors.forename: Sung Kwan
authors.initials: SK
authors.lastname: Yoon
authors.forename: Jong Kwang
authors.initials: JK
authors.lastname: Hong
authors.forename: Seung Ho
authors.initials: SH
authors.lastname: Choo
authors.forename: Ji Yong
authors.initials: JY
authors.lastname: Song
authors.forename: Hong Woo
authors.initials: HW
authors.lastname: Park
authors.forename: Gyun Min
authors.initials: GM
authors.lastname: Lee
mesh_terms: D000064:Acclimatization; D000818:Animals; D015139:Blotting, Southern; D016466:CHO Cells; D018929:Cell Culture Techniques / Q000379:methods*; D002470:Cell Survival; D003080:Cold Temperature; D006224:Cricetinae; D004921:Erythropoietin / Q000096:biosynthesis / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000096:biosynthesis / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013696:Temperature; D013997:Time Factors
chemical_list: C491390:CIRBP protein, human; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D004921:Erythropoietin; D005640:Follicle Stimulating Hormone