Viral vectors for production of recombinant proteins in plants

Abstract

Global demand for recombinant proteins has steadily accelerated for the last 20 years. These recombinant proteins have a wide range of important applications, including vaccines and therapeutics for human and animal health, industrial enzymes, new materials and components of novel nano-particles for various applications. The majority of recombinant proteins are produced by traditional biological "factories," that is, predominantly mammalian and microbial cell cultures along with yeast and insect cells. However, these traditional technologies cannot satisfy the increasing market demand due to prohibitive capital investment requirements. During the last two decades, plants have been under intensive investigation to provide an alternative system for cost-effective, highly scalable, and safe production of recombinant proteins. Although the genetic engineering of plant viral vectors for heterologous gene expression can be dated back to the early 1980s, recent understanding of plant virology and technical progress in molecular biology have allowed for significant improvements and fine tuning of these vectors. These breakthroughs enable the flourishing of a variety of new viral-based expression systems and their wide application by academic and industry groups. In this review, we describe the principal plant viral-based production strategies and the latest plant viral expression systems, with a particular focus on the variety of proteins produced and their applications. We will summarize the recent progress in the downstream processing of plant materials for efficient extraction and purification of recombinant proteins.

Manufacturing antibodies in the plant cell

“…Initially, transient expression technologies were based solely on recombinant viral vectors, which spread recombinant protein production as they infect the plant (see [74] for a review on viral expression systems). However, the relatively big size of the antibody chains imposes a handicap in viral replication and movement, and clonal exclusion precludes the coinfection in a single cell with two viral vectors containing heavy and light chains.…”

“…Deleted: [72] Deleted: top Deleted: [73] Deleted: [74] Deleted: based in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 ensures cell-to-cell spreading of the replicon throughout the entire agroinfiltrated leaf [79,80]. Since RNA viruses do not enter the nucleus in its natural life cycle, Icon's vector was elegantly tailored for its artificial nucleus-to cytoplasm passage by addition of introns and removal of cryptic splicing sites [81].…”

Transient Virus Expression Systems for Recombinant Protein Expression in Dicot- and Monocotyledonous Plants

“…The apparent pausing of the ribosome, and the discontinuity of the peptide bond that results, allows proteins upstream and downstream of the 2A sequence to be differentially targeted, such as a single chain antibody accumulating in the plant apoplast while the CP was sequestered in its normal cytosolic localization [43]. Using these strategies, independent-virus systems have been derived from the genomes of potexviruses (including potato virus X; PVX), tobamoviruses (including TMV), comoviruses (including cowpea mosaic virus), potyviruses, tobraviruses, closteroviruses and others [12,13,15].…”

“…The rapid replication cycle of the virus systems provided amplification of messenger RNA and the resulting proteins providing for a "burst" of recombinant expression that can provide impressive yields (reviewed in [12][13][14][15]). While these early vectors were useful in plant cell systems to produce recombinant protein products with potential market value [16], these early systems could not support large scale manufacturing nor did they exploit the advantages of agriculture to provide cost-effective products.…”

Mycoviruses: future therapeutic agents of invasive fungal infections in humans?

“…Indeed, recombinant viruses expressing foreign antigenic peptides on their surface can remain infectious and retain the foreign sequences during passage from plant to plant [73,76]. Many stable mutants have already been prepared that allow specific modification of the capsid surface of plant viruses (for a review, see [77]). …”