Vaccines from the‘Backyard’

The use of plants as a source of medicines is prevalent from the earliest stages of civilization. With the development of bioscience technology, it is now common knowledge that plants are a potential source of pharmaceutical proteins including vaccines, antibodies, blood substitutes, and other therapeutic entities. These vaccines are basically ‘Edible Vaccines’.

The edible vaccines are oral, subunit vaccines that stimulate both the systematic and mucosal immune network. Banana, potato, lettuce, tobacco, wheat, soybean, rice, spinach, corn, legumes, tomato and Arabidopsis are some of the plants from which researchers have been successful in obtaining these vaccines. These edible vaccines are capable of triggering an animal’s immune system.

Edible vaccines would be preferred over conventional vaccines for the following reasons:
1) It cuts the use and disposal of needles and syringes.
2) No trained personnel are required to administer injections.
3) Refrigeration is not required during shipping and storage.
4) These are free of mammalian viral vectors and human pathogens.
5) Adjuvants are not necessary to enhance immune response.
6) Production cost is low.
7) Extraction and purification are not required.
8) Ease of mass production, etc.
However, many issues must still be addressed such as low yield, immunogenicity, accumulation and stability of the transproteins, obtainment of glycosylation that is normally observed in humans, and contamination of food crops through cross-pollination and of the vaccine itself through plant debris that spread as pollutants in air and groundwater. The vaccine antigen may affect grazing animals and humans living in the area who may drink vaccine-polluted water or breathe vaccine-polluted dust. Cultivation and production of these plants are restricted to greenhouse or plant tissue culture.

Considering the potentials we, indeed, need to think of overcoming the problems which we face as a result of using these vaccines. Both the public and the government should encourage and work towards a more rapid development of this technology.

I would finally conclude that a combination of strong and adaptable regulatory oversight with technological solutions is required to make edible vaccines a potential tool to fight against many existing diseases.

By Geetha T.R