4) More Information
Vaccine saves many people from deadly diseases. Plant-based vaccine as a new branch of vaccine brings a lot of attentions recently. Although it has been about thirty years since the first plant-based vaccine was invented, the only approved one in the United States is a Newcastle disease vaccine and several candidate vaccines are in clinical trials.
Plant-based vaccine has many advantages. "These include: (1) the ability to carry out post-translational modifications similar to other higher eukaryotes; (2) the ability to rapidly scale-up and produce extremely large quantities; (3) the potential for greatly reduced costs of raw material and (4) the reduced fear of using plants, which do not harbour human pathogens.Food-based crops offer additional advantages if the vaccine can be delivered orally, by eliminating purification steps and delivering the product in a safe and palatable formulation. If a grain crop is used, the potential to store the vaccine at ambient temperature without adverse effects may remove the need for a cold chain (Kusnadi et al., 1998). It has also been shown that plants can express multiple transgenes at one time (Howard, unpublished)."
"Genes can be introduced into plants either directly or by using the gram-negative bacterium Agrobacterium tumefaciens. Plant transformation with polyethyleneglycol or by electroporation usually includes protoplast preparation by removing the cell wall, which requires time and skill. Almost half of plant transformation technologies use A. tumefaciens, which infects plants naturally. The T-DNA region between the left and right borders of the A. tumefaciens Ti plasmid is introduced into plant genome and transcribed in the plant cell; this process induces abnormal plant hormone production, resulting in crown gall disease. The T-DNA region can be replaced with a gene of interest, and the Ti plasmid has been modified into a binary vector that can be manipulated in Escherichia coli [Bevan, 1984]."
More Information:Plant-based Vaccines for Animals and Humans (PMC) Plant-based Vaccines (IJP)