EDIBLEVaccine

Types of Vaccines

Lives Vaccines

Killed vaccines

Attenuated Vaccines

Recombinant Vaccines

What is plant-based edible vaccine?

Plant materials administered via the oral route. Using transgenic plants that express antigen proteins

capable of inducing protective immunity against various human and animal diseases to induce specific immune responses

Future Prospects

Avoidance of transmission of blood-borne infections (HIV, hepatitis B, hepatitis

C)

Lack of necessity for direct involvement of nurses and physicians

The logistical and economic assets are clear:

Low production of cost

Avoidance of needles and syringes leads to

less likelihood of contamination

The production of medically useful proteins using transgenic plants initially drew public attention when Nature published a manuscript in 1989 describing the production of monoclonal antibody from the tobacco plant.

Monoclonal antibodies are utilized for a variety of purposes, including the treatment of arthritis and cancer.

The production of monoclonal antibody via a plant expression system has lowered the price of the production of 1 Kg of monoclonal antibody from 3 million dollars to 100 dollars.

Plant-based edible vaccine technology, if sufficiently developed, may offer several advantages.

For example, it is easy to apply, store, and transport.

It could also induce both mucosal and systemic immune responses, which cannot be achieved using an injection vaccine.

Plant-based vaccines are also anticipated to prove quite useful in the animal industry, since the cost of injection is a significant burden in the animal industry.

Vaccine material is extremely precious for people in underdeveloped and developing countries, to whom the vaccine materials are not available due to economic issues.

Although no commercial plant-based edible vaccines are currently available, several candidate vaccines are undergoing clinical trials.

Since the plant-based edible vaccine can efficiently induce mucosal immune responses, which is not feasible with a conventional injection vaccine, the technology is quite useful for the development of vaccines against gastrointestinal infectious diseases.

Plant-based edible vaccines do not require a cold chain to preserve the vaccine; hence, the technology is very useful for vaccines to be used in countries without concrete health infrastructure.

Plant-based edible vaccines may constitute one of the best and most effective candidates for vaccines to be administered to children.

Diarrhoeal disease and its complications remain a major cause of morbidity and mortality in children, especially in developing countries.

It is the second most common cause of death in children under five years of age worldwide and is responsible for 2.4 million deaths each year.

Rotarix has been licensed in South Africa since 2006 and was introduced in the Extended Programme of Immunisation in 2009.

It is a live attenuated human rotavirus strain, with two doses given orally four weeks apart, not after six months.

In studies in middle-income countries the vaccine has a very good safety profile and efficacy of 85% protection.

Rotavirus Vaccine

Banana, potato, tomato, corn, rice, wheat, and barley are considered as possible target plants due to the efficiency with which they can be stored and transported, as well as the fact that the plants are largely consumable.

In particular, alfalfa and corn, which are major ingredients in animal feed, are considered good target plants for the development of plant-based edible vaccines for use in animals.

Those plants have been shown to be feasible in the antigen gene transformation of Agrobacterium-mediated and gene gun methods.

The major disadvantage of the banana plant is the time that must elapse from first introduction of new genes to harvest of the fruit, estimated to be 2 or 3 years.

However, enthusiastic plant biologists have already calculated the numbers of tons of bananas that would be necessary to provide global immunization, a target well within agricultural capability.

If appropriate systems can be developed from edible plants expressing antigens in their tissues, these naturally bio-encapsulated vaccines could be ingested with subsequent release of antigen as foods were degraded in the human gastrointestinal tract.

Contact of the bio-encapsulated vaccine with the extensive gastrointestinal-associated lymphoid tissue could induce mucosal immunity followed soon after by humoral immunity secondary to the trafficking of lymphoid cells.

Since this technology utilizes the most advanced modern vaccine manufacturing and vaccination technologies, the social and economical impact of the technology might prove to be enormous.

Consequently, many scientists are anticipating that a commercial plant-based edible vaccine will be available in the near future.

Based on a report asserting that phase III human trials are currently meeting with success, it is conceivable that commercial plant-based edible vaccine products may become available soon.