Agroinfiltration as an Effective and Scalable Strategy of Gene Delivery for Production of Pharmaceutical Proteins

Abstract

Current human biologics are most commonly produced by mammalian cell culture-based fermentation technologies. However, its limited scalability and high cost prevent this platform from meeting the ever increasing global demand. Plants offer a novel alternative system for the production of pharmaceutical proteins that is more scalable, cost-effective, and safer than current expression paradigms. The recent development of deconstructed virus-based vectors has allowed rapid and high-level transient expression of recombinant proteins, and in turn, provided a preferred plant based production platform. One of the remaining challenges for the commercial application of this platform was the lack of a scalable technology to deliver the transgene into plant cells. Therefore, this review focuses on the development of an effective and scalable technology for gene delivery in plants. Direct and indirect gene delivery strategies for plant cells are first presented, and the two major gene delivery technologies based on agroinfiltration are subsequently discussed. Furthermore, the advantages of syringe and vacuum infiltration as gene delivery methodologies are extensively discussed, in context of their applications and scalability for commercial production of human pharmaceutical proteins in plants. The important steps and critical parameters for the successful implementation of these strategies are also detailed in the review. Overall, agroinfiltration based on syringe and vacuum infiltration provides an efficient, robust and scalable gene-delivery technology for the transient expression of recombinant proteins in plants. The development of this technology will greatly facilitate the realization of plant transient expression systems, as a premier platform for commercial production of pharmaceutical proteins.

Efficient Agroinfiltration of Plants for High-level Transient Expression of Recombinant Proteins

“…Furthermore, this process can be further scaled-up for commercial manufacture of pharmaceutical proteins from plants. For example, processes are being designed to vacuum infiltrate three metric tons of N. benthamiana plants per hour in a scale-up operation 24 . Another advantage of vacuum infiltration is that it can be used to agroinfiltrate plant species that are not amenable for syringe infiltration.…”

Purification of monoclonal antibody against Ebola GP1 protein expressed in Nicotiana benthamiana

“…temperature, light intensity and fertilizer are the most likely factors in causing variability of recombinant protein yield among production batches and among laboratories [21]. Thus, one possible reason for the significant discrepancy in 6D8 yield is that the soil components and other conditions for plant growth are not identical compared with those reported previously, and thus not optimal for achieving high levels of mAb accumulation [22]. …”

Molecular farming on rescue of pharma industry for next generations

“…Hybrid vectors that combine genetic elements of bacterial binary plasmids and viral vectors would have a substantial impact on the expression level of targeted recombinant proteins (Yusibov et al, 2013). Agroinfiltration, based on syringe and vacuum infiltration, would provide an efficient, robust and scalable gene-delivery system for commercial production of biodrugs in plants (Chen et al, 2013). However, targeting the nuclear genome to express foreign proteins is associated with some inconveniences including random insertion, instability of the transgene, sterility and propagation risk of the transgene through pollens and low expression levels.…”