Transgenic plants for animal health: plant-made vaccine antigens for animal infectious disease control

Abstract

A variety of plant species have been genetically modified to accumulate vaccine antigens for human and animal health and the first vaccine candidates are approaching the market. The regulatory burden for animal vaccines is less than that for human use and this has attracted the attention of researchers and companies, and investment in plantmade vaccines for animal infectious disease control is increasing. The dosage cost of vaccines for animal infectious diseases must be kept to a minimum, especially for non-lethal diseases that diminish animal welfare and growth, so efficient and economic production, storage and delivery are critical for commercialization. It has become clear that transgenic plants are an economic and efficient alternative to fermentation for large-scale production of vaccine antigens. The oral delivery of plant-made vaccines is particularly attractive since the expensive purification step can be avoided further reducing the cost per dose. This review covers the current status of plantproduced vaccines for the prevention of disease in animals and focuses on barriers to the development of such products and methods to overcome them.

Hydrophobin Fusions for High-Level Transient Protein Expression and Purification inNicotiana benthamiana

“…Insufficient recombinant protein yields in transgenic plants and the lack of efficient purification methods for their recovery remain a major hindrance for the advancement of plant biology and biotechnology (Doran, 2006;Joensuu et al, 2008;Kaiser, 2008). Recent developments in transient plant expression systems based on Agrobacterium infiltration have shown great promise for boosting expression with the aid of plant viral vectors (Marillonnet et al, 2005;Giritch et al, 2006;Lindbo, 2007) and/or posttranscriptional gene-silencing suppressors (Silhavy et al, 2002;Voinnet et al, 2003;Sainsbury and Lomonossoff, 2008).…”

High expression level of a foot and mouth disease virus epitope in tobacco transplastomic plants

“…Given that the regulatory burden is less for veterinary health than for human use (Joensuu et al 2008), the Wrst plant-made vaccine that obtained FDA approval was for the poultry industry (Vermij and Waltz 2006). One of the most feared diseases that aVect livestock, particularly clovenhooved animals (cattle, swine, sheep and goats), is caused by the foot and mouth disease virus (FMDV).…”

Towards Using Biotechnology to Modify Soybean Seeds as Protein Bioreactors

“…In these studies that utilized strong tissue-specific seed storage protein promoters, the fraction of the total seed protein encoded by the transgene was significantly less than expected from either homologous or heterologous seed storage protein promoters. Typical results for expressing seed storage proteins in transgenic model seed systems yielded less than 1 % of the total seed protein (Hoffman et al 1987(Hoffman et al , 1988Garg et al 2007;Joensuu et al 2008;Moravec et al 2007;Alvarez et al 2010), which is far less than would be expected by a proportional allocation of source to produce the seed sink, including the transgene. For instance, if a transgene driven by a storage protein promoter was added in a single copy as an extra gene to a gene family of five endogenous storage protein genes, it would be expected that the transgene-encoded protein should represent roughly one sixth of the total seed-storage protein.…”

“…There have been numerous projects aimed at developing this technology, leading to the demonstration that it is feasible to produce protein antigens in plants that display immunogenic epitopes, eliciting a protective immune response (Ma et al 2003(Ma et al , 2005Streatfield et al 2003;Fischer et al 2004;Daniell et al 2001;Boothe et al 2010). Antigens have been expressed in leaves, fruits, and seeds for oral delivery (Richter et al 2000;Rigano et al 2004;Piller et al 2005;Obregon et al 2006;Garg et al 2007;Moravec et al 2007;Nochi et al 2007;Joensuu et al 2008;Oakes et al 2009;Joensuu et al 2009;Alvarez et al 2010). Plants have also been tested as production systems for vaccines to be purified from plant extracts.…”