Vaccines from ‘Backyard’

By Geetha

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 potentially a new source of pharmaceutical proteins including vaccines, antibodies, blood substitutes and other therapeutic entities. These vaccines are basically ‘Edible Vaccines’.

These edible vaccines are capable of triggering an animal’s immune system. 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.

Edible vaccines would be preferred over conventional vaccines for the following reasons:

1) Cutting the use and disposal of needles and syringes

2) No trained personnel required to administer injections

3) Refrigeration is not required during shipping and storage

4) Vaccines are free of mammalian viral vectors and human pathogens

5) Adjuvant is not necessary to enhance immune response

6) Production cost is low

7) Extraction and purification not required

8) Ease of mass production so on…

However, many issues must still be addressed such as low yield, immunogenicity, accumulation and stability of the transproteins, obtaining glycosylation that are normally observed in humans, contamination of food crops through cross pollination and of the vaccine itself in plant debris spreading as pollutant in air and groundwater. The vaccine antigen may affect grazing animals and humans living in the area who may drink vaccine-polluted water or breathing vaccine-polluted dust, cultivation and production of these plants are restricted to green house or plant tissue culture.

Considering the potentials, we indeed, need to think of overcoming the problems which are faced for the acceptance of these vaccines. Public and Government should encourage to open the way towards a more rapid development of this technology.

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