Productivity and Quality of Recombinant Proteins Produced by Stable CHO Cell Clones can be Predicted by Transient Expression in HEK Cells

Abstract

Selection of lead candidates in drug discovery is a complex and time-consuming process. Here, we describe an approach that allows prediction of the productivity and quality of recombinant proteins by stable producer cell clones with the help of transient transfection studies. This is exemplified for three distinct bispecific T cell engager (BiTE(®))-a new class of single-chain antibody-based therapeutics showing very promising results in the treatment of cancer. BiTE(®) titers of transiently transfected HEK cells showed a striking correlation with titers of selected stable CHO cell clones. Likewise, the percentage of the monomeric BiTE(®) fraction in cell culture supernatants correlated well between transiently expressing HEK and stably expressing CHO cell clones. This validates the use of transient transfection studies for the selection of biopharmaceutical lead candidates with desired pharmaceutical properties.

Stable and Transient Expression of Human Coagulation Factor IX in Mammalian Expression Systems; CHO Versus HEK Cells

“…2017; 4(2):e13096. (11). They also showed the CHO cells are not well suited to deliver reasonable amounts of protein following transient transfection (11).…”

“…This is attributable to the fact that the largescale transfection of CHO cells has low efficiency and low productivity when cost-effective transfection reagents are used. On the other hand, CHO cells, which are widely used for stable transfection, are not well suited to deliver adequate amounts of protein following transient transfection (11). HEK cells have generated the highest volumetric yields in TGE systems, and are therefore the most widely used (23).…”

“…In addition to transfection efficiency comparison of both cells with reagent-FreeStyle TM MAX (6), polyethyleneimine (PEI) reagents (7), or in a suspension culture (8), multiple studies have reported differences in the glycosylation patterns of proteins when produced in CHO versus HEK cells (9,10). Furthermore, a few single publications report differences in expression levels of recombinant proteins in HEK and CHO cells (11,12). It has been showed that the expression of bispecific T cell engager (BiTE) antibody in transient HEK cells is higher than CHO cells (11).…”

“…Furthermore, a few single publications report differences in expression levels of recombinant proteins in HEK and CHO cells (11,12). It has been showed that the expression of bispecific T cell engager (BiTE) antibody in transient HEK cells is higher than CHO cells (11). A recent review by Durocher and Butler (12) report differences in expression levels as well as biological activity.…”

Cell Culture Processes for Biopharmaceutical Manufacturing

“…There is a significant time investment of 2-6 months required for the development of a stable cell line precluding the use of stable cell lines for evaluation of various biological elements. Transient gene expression can help to rapidly express recombinant protein for initial evaluation of the effect of plasmid elements and host cells on the quality of recombinant therapeutic prior to establishing a stable cell line 25 , and can be scaled up to rapidly producing material for pre-clinical evaluation. 29 .…”