CHO and Other Cell Line Development

Generation of CHO cell lines producing a recombinant protein typically starts with the transfer of an expression vector carrying the gene of interest together with a selectable marker into the cells. See MoreThe goal is to identify stable CHO cells that produce high titres of a biologically active recombinant protein, such as a monoclonal antibody. Incorporating the use of a selectable marker in the transfection process enables cells that have taken up the incoming exogenous DNA to be identified by virtue of their resistance to a particular compound (e.g. an antibiotic such as G418 or hygromycin) or their ability to overcome a blockage in a metabolic pathway. Cells stably expressing the co-transfected gene of interest are subsequently identified with a suitable assay such as ELISA, or by a functional screen. Regardless of the selection method, performing selection in semi-solid CHO medium offers major advantages for cell line development: cloning is performed concurrently with selection, thereby shortening the cell line development cycle, and the potential loss of rare but highly productive clones is minimized. On the other hand, if selection has been performed in liquid media the next step is to isolate clonal cell lines.