Chinese Hamster Ovary Kl Host Cell Enables Stable Cell Line Development for Antibody Molecules Which Are Difficult to Express in DUXBll-Derived Dihydrofolate Reductase Deficient Host Cell

摘要

Therapeutic monoclonal antibodies (mAb) are often produced in Chinese hamster ovary (CHO) cells. Three commonly used CHO host cells for generating stable cell lines to produce therapeutic proteins are dihydrofolate reductase (DHFR) positive CHOK1, DHFR-defi-cient DG44, and DUXB11-based DHFR deficient CHO. Current Genentech commercial full-length antibody products have all been produced in the DUXB11-derived DHFR-deficient CHO host. However, it has been challenging to develop stable cell lines producing an appreciable amount of antibody proteins in the DUXB11-derived DHFR-deficient CHO host for some antibody molecules and the CHOK1 host has been explored as an alternative approach. In this work, stable cell lines were developed for three antibody molecules in both DUXBll-based and CHOK1 hosts. Results have shown that the best CHOK1 clones produce about 1 g/l for an antibody mAbl and about 4 g/l for an antibody mAb2 in 14-day fed batch cultures in shake flasks. In contrast, the DUXBll-based host produced ~0.1 gll for both antibodies in the same 14-day fed batch shake flask production experiments. For an antibody mAbS, both CHOK1 and DUXB11 host cells can generate stable cell lines with the best clone in each host producing ~2.5 gll. Additionally, studies have shown that the CHOK1 host cell has a larger endoplasmic reticulum and higher mitochondrial mass.