Microscale to manufacturing scale‐up of cell‐free cytokine production—a new approach for shortening protein production development timelines

TLDR

Cell‑based production of biotherapeutic proteins is difficult because it requires maintaining complex cellular networks and developing reproducible downstream processes to achieve high product quality. The study introduces an E. coli‑based open cell‑free synthesis system designed for predictable, high‑yield protein production and folding at any scale with simple downstream purification. The OCFS platform scales linearly, enabling rapid optimization of extract activation, gene sequence, and redox folding conditions for disulfide bonds even at microliter volumes.

Abstract

Engineering robust protein production and purification of correctly folded biotherapeutic proteins in cell-based systems is often challenging due to the requirements for maintaining complex cellular networks for cell viability and the need to develop associated downstream processes that reproducibly yield biopharmaceutical products with high product quality. Here, we present an alternative Escherichia coli-based open cell-free synthesis (OCFS) system that is optimized for predictable high-yield protein synthesis and folding at any scale with straightforward downstream purification processes. We describe how the linear scalability of OCFS allows rapid process optimization of parameters affecting extract activation, gene sequence optimization, and redox folding conditions for disulfide bond formation at microliter scales. Efficient and predictable high-level protein production can then be achieved using batch processes in standard bioreactors. We show how a fully bioactive protein produced by OCFS from optimized frozen extract can be purified directly using a streamlined purification process that yields a biologically active cytokine, human granulocyte-macrophage colony-stimulating factor, produced at titers of 700 mg/L in 10 h. These results represent a milestone for in vitro protein synthesis, with potential for the cGMP production of disulfide-bonded biotherapeutic proteins.