Virology News

Plant expression systems based on nonreplicating virus-based vectors can be used for the simultaneous expression of multiple genes within the same cell. They therefore have great potential for the production of heteromultimeric protein complexes. This work describes the efficient plant-based production and assembly of Bluetongue virus-like particles (VLPs), requiring the simultaneous expression of four distinct proteins in varying amounts. Such particles have the potential to serve as a safe and effective vaccine against Bluetongue virus (BTV), which causes high mortality rates in ruminants and thus has a severe effect on the livestock trade. Here, VLPs produced and assembled in Nicotiana benthamiana using the cowpea mosaic virus-based HyperTrans (CPMV-HT) and associated pEAQ plant transient expression vector system were shown to elicit a strong antibody response in sheep. Furthermore, they provided protective immunity against a challenge with a South African BTV-8 field isolate.

 

The results show that transient expression can be used to produce immunologically relevant complex heteromultimeric structures in plants in a matter of days. The results have implications beyond the realm of veterinary vaccines and could be applied to the production of VLPs for human use or the coexpression of multiple enzymes for the manipulation of metabolic pathways.

 Generic reovirus-like particle by Russell Kightley Media

"Transgenic plants present enormous potential as a cost-effective and safe platform for large-scale production of vaccines and other therapeutic proteins. A number of different technologies are under development for the production of pharmaceutical proteins from plant tissues. One method used to express high levels of protein in plants involves the employment of plant virus expression vectors. Plant virus vectors have been designed to carry vaccine epitopes as well as full therapeutic proteins such as monoclonal antibodies in plant tissue both safely and effectively. Biopharmaceuticals such as these offer enormous potential on many levels, from providing relief to those who have little access to modern medicine, to playing an active role in the battle against cancer. This review describes the current design and status of plant virus expression vectors used as production platforms for biopharmaceutical proteins."

 

And of course, let it not be forgotten that our group has pioneered the use of mastreviruses in this regard: maize streak virus in 1999-2001, and bean yellow dwarf in 2010 and since.

Investigation of the potential of maize streak virus to act as an infectious gene vector in maize plants.

Palmer KE, Rybicki EP.
Arch Virol. 2001;146(6):1089-104.

Generation of maize cell lines containing autonomously replicating maize streak virus-based gene vectors.
Palmer KE, Thomson JA, Rybicki EP.
Arch Virol. 1999;144(7):1345-60.

 

High level protein expression in plants through the use of a novel autonomously replicating geminivirus shuttle vector.
Regnard GL, Halley-Stott RP, Tanzer FL, Hitzeroth II, Rybicki EP.
Plant Biotechnol J. 2010 Jan;8(1):38-46. Epub 2009 Nov 19.

 

...not to mention a treatise on ssDNA virus vectors in plants:

 

Virus-Derived ssDNA Vectors for the Expression of Foreign Proteins in Plants.
Rybicki EP, Martin DP.
Curr Top Microbiol Immunol. 2011 Oct 29. [Epub ahead of print]