Vaccines are developed many different ways, all of which use a non-infectious version of a virus or disease antigen intended to trigger an immune response to a virus or disease. The body is then conditioned to defend itself against encounters with the virus or disease.
In the plant-based vaccine development process, living plants are used as bioreactors to produce a non-infectious particle that mimics the target virus. This is all done without the use of any live viruses.
Our plant-based vaccine platform is versatile, designed to produce both vaccines and antibodies – with a combination of speed, accuracy, and adaptability that is designed to produce safe and efficacious vaccines and therapies that can be used to rapidly respond to emerging pandemics or global needs.
Once a virus has been genetically sequenced, Medicago uses its Proficia® technology to synthesize the virus’s code so that its genetic instructions can be “read” by plants.
The Proficia® technology developed by Medicago is unique. It uses Nicotiana benthamiana plants, which is the most widely used experimental host in plant virology, due mainly to the large number of viruses that can successfully infect it. The natural cell process of Nicotiana benthamiana is therefore temporarily exploited to produce virus-like particles (VLPs).
i Vaccines Europe . How are vaccines produced?. Consulté en septembre 2021.
ii Bally, J et al. Nature Plants. The extremophile Nicotiana benthamiana has traded viral defence for early vigour. Consulté en septembre 2021.
We start with a gene sequence or code of a virus. We then use our technology to synthesize the virus code. The code contains genetic instructions that our plants can ‘read’, and we insert it into bacteria that carries the information into the plant’s cells.
The plants are immersed in a liquid that contains a bacterium called Agrobacterium tumefaciens, which contains a sequence of a part of a virus gene. Using a vacuum, the air between the plant cells is sucked out. The plants then act like sponges, absorbing the liquid and the Agrobacterium tumefaciens that it contains.
At the end of this bacterial bath, the plants are placed for at least four days in a carefully controlled greenhouse so that they can continue to grow. During this period the plants quickly produce large quantities of the most important ingredient in our vaccines: virus-like particles, or VLPs.
When the growing is done, we harvest the plants, blending the leaves into a solution to extract the virus-like particles. These particles mimic the structure of the virus in order to convince the immune system to recognize them as a virus that the body must protect itself against. However, these VLPs do not contain genetic material, making them non-infectious.
VLPs are extracted from the leaves of mature plants and then purified to produce the final material that will be used in the creation of our vaccines.
