Plant-based vaccines for animal health.

Plant-based vaccines are recombinant protein subunit vaccines. Ideally, the choice of plant species used to produce the selected antigen should allow for oral delivery in the form of an edible vaccine. These vaccines are well suited to combat diseases where there is a clear antigen candidate, and where the costs of production or delivery for any current vaccine are prohibitive. Several academic and industrial research groups are currently investigating the use of plant-based vaccines in both humans and animals. To date, the most advanced human vaccine projects have successfully completed phase I clinical trials, and animal vaccine projects have given promising data in early phase trials targeting specific animal species. In this article the advantages offered by plant-based vaccines will be presented, progress on the most advanced vaccine candidates will be summarised, and the path ahead will be outlined. Although the focus of this paper is on the application of plant-based vaccines in the field of animal health, principally their use in domestic livestock, examples of the use of plant-based vaccines in the field of human health will also be discussed.