Using Fast-growing Tobacco Plants To Develop a COVID-19 Vaccine

British American Tobacco (BAT)’s US bio-tech subsidiary, Kentucky BioProcessing (KBP), is developing a potential vaccine for COVID-19 – which is now undergoing preclinical testing. KBP has a track record of successful therapeutic development, being one of the very few companies to develop an effective treatment for Ebola.

Technology Networks recently spoke to David O’Reilly, PhD, Director of Scientific Research at BAT to learn more about the tobacco plant “biomanufacturing factories” that are being used to develop a COVID-19 vaccine. We also discuss the challenges faced when developing a vaccine and the benefits tobacco plants offer compared to conventional vaccine development methods.

Q: Could you tell us more about the process of transforming tobacco plants into “biomanufacturing factories”?

A: The technologies and processes that our bioprocessing unit develops make it possible to harness the biochemical processes of tobacco plants to produce specific complex proteins more efficiently and effectively than they can be produced using more traditional methods. The tobacco production system offers a much faster and less expensive way to move from product concept to actually having material in hand.

We develop and execute processes to transform tobacco plants into “biomanufacturing factories” that efficiently produce complex proteins they would not otherwise produce. It represents a rapid production cycle that typically takes about 6 weeks – compared with many months using traditional biomanufacturing methods.

We use licensed and proprietary technologies to transiently express genes in fast growing tobacco plants to produce specific target proteins with high fidelity. The plants are grown in an automated, climate-controlled environment that can be adjusted to optimize their production of a protein of interest.

Q: Can you tell us more about the vaccine candidate you are developing for the treatment of COVID-19?

A: Kentucky BioProcessing (KBP) recently cloned a portion of the genetic sequence encoding the selected coronavirus antigen – a substance which induces an immune response in the body and the production of antibodies. This sequence was then inserted into tobacco plants for rapid multiplication production and, once the plants were harvested, the antigen was then purified, conjugated with the tobacco mosaic virus (TMV) scaffold (a unique type of adjuvant) and is now undergoing preclinical testing.

We are now exploring partnerships with government agencies to bring our candidate vaccine to clinical testing as soon as possible. Through collaborations with government and third-party manufacturers, we believe that between 1 and 3 million doses per week could be manufactured from June.

Q: What are some of the challenges encountered when developing a vaccine?

A: Vaccine development is challenging and complex work, as there are many stages to the process from safety and testing to validation and regulatory approval. We believe we have made a significant breakthrough with our tobacco plant technology platform and stand ready to work with governments and all stakeholders to help win the war against COVID-19.

Q: Why do tobacco plants offer the potential for faster and safer vaccine development compared to conventional methods?

A: It is faster because the elements of the vaccine accumulate in tobacco plants much more quickly – 6 weeks in tobacco plants versus several months using conventional methods. Furthermore, the vaccine formulation we are developing at KBP remains stable at room temperature, unlike conventional vaccines which often require refrigeration.

It is potentially safer given that tobacco plants can’t host pathogens which cause human disease and it also has the potential to deliver an effective immune response in a single dose.

Q: Would the tobacco plant used to manufacture the vaccine be deemed a GMO? What regulatory terms surround developing vaccines in this way?

A: Yes, however, the tobacco plants are destroyed during harvesting and the only product kept at the end of the process is the purified antigen and the TMV scaffold.

Q: In the press release BAT said: "Through collaborations with government and third-party manufacturers, BAT believes that between 1 and 3 million doses per week could be made". How will you ensure that the physical space is available to grow the required amount of plants to achieve this proposed figure?

A: We are looking for help from governments to accelerate clinical trials to demonstrate the candidate vaccine is safe and effective. We also need help with downstream manufacturing in terms of conjugation and dispensing. We are also open to working with governments and other partners to build scaled up manufacturing outside the USA. This is non-competitive and we are open to collaboration with other vaccine producers and share technology.

To this end, we have blueprints and plans to replicate the Kentucky facility elsewhere. This can be scaled to increase output beyond that currently available.

David O’Reilly, PhD, was speaking with Laura Elizabeth Lansdowne and Molly Campbell, Science Writers for Technology Networks.