(BQ) Part 2 book “Update on production of recombinant therapeutic protein - Transient gene expression” has content: Optimisation of transient gene expression for therapeutic protein production, clinical applications of the transient gene expression. | 3 Optimisation of Transient Gene Expression for Therapeutic Protein Production Jianwei Zhu Transient gene expression (TGE) is a well-established technology for rapid generation of recombinant proteins with human embryonic kidney (HEK) and Chinese hamster ovary (CHO) cell lines. Many TGE protocols have been published over the last ten years. A number of representative protocols are described in the last section of Chapter 2 for producing therapeutic proteins at different scales (from 10 mL -100 L), facilitated by calcium phosphate or polyethylenimine (PEI), using viral or non-viral vectors. The protocol using 25 kDa linear PEI (Table ) as a transfection component to form a plasmid/ PEI complex for transfecting CHO and HEK cells has been widely accepted by many laboratories and the biopharmaceutical industry. Scalability and expression levels of TGE have improved significantly in the past few years to the extent that it is now feasible to produce 100 g of protein for preclinical studies or even early phase clinical development of therapeutics. Successful reports from the past few years are listed and summarised in Table . Table presents the representative productivity level with the TGE technology platform. Since 2008, when the production titre first reached the 1 g/L milestone [1], there have been repeatedly successful results either through TGE [2] or stable transfection pools [3] at, or over, 1 g/L expression levels, making it feasible to use the TGE system to produce therapeutic proteins in sufficient quantity for preclinical studies or even early stage clinical trials. In the successful examples (Table ) both CHO and HEK293 cells were predominantly used as host cell lines. Great effort has been invested into optimisation of many aspects of the TGE system in coexpression of antiapoptosis genes [1], the use of new additives in the media [4, 5], and transfection 81 82 Expression 81 mg/L 1000 mg/L 50 mg/L 80 .
