Edible Vaccines

Edible Vaccines
Ever heard of edible vaccines? Yes it’s true!
Conventional vaccines consist of attenuated or inactivated pathogens. These vaccines are produced through bacterial fermentation or in animal cell cultures, which often makes their cost prohibitively high. This has prevented their wide use, especially in developing countries where they also face problems of storage and transport. There is thus a need to develop alternate vaccine production and delivery systems. To this effect, plants are being used for development of edible vaccines.
Edible vaccines:
Plant derived vaccines are produced using the gene encoding the orally active antigenic protein and a suitable gene construct for constitutive expression. In short, antigens of several pathogens are introduced and stable integrated into the genome of selected plant species, and are expressed to produce the antigen. Thus appropriate plant parts can be fed to animals or humans to bring about immunization.
Edible vaccine research is currently directed at human diseases, with a special emphasis on the developing world. Vaccines against bacterial diseases such as diarrhea are being developed. Edible vaccines against viral diseases such as rinderpest, rabies, hepatitis and acute epidemic gastroenteritis are also being developed. Also, strategies are being developed for delivery of vaccine by infecting plants with recombinant viruses carrying the desired antigen to produce large amounts of antigens within a short time. Such vaccines are being developed against malaria, foot and mouth disease, HIV, etc.
The technology will also have immediate value for the production of inexpensive vaccines as feed additives for agricultural animals.
One of the major challenges of biotechnology is to reduce clinical innovations to economically viable practices. Plant-derived edible vaccines were first conceived and are continuing to be developed with this prime directive in mind. The theory behind this is now put to clinical trials.
Edible vaccine will prove better than traditional vaccine technology. Traditional vaccines consist of inactivated or attenuated strains of pathogens, which are almost always delivered by injection except oral polio vaccine. Immunization by injection rarely results in specific protective immune responses at the mucosal surfaces of respiratory, gastrointestinal and genito-urinary tracts. Since plant derived vaccines are consumed orally so they provide a compelling new opportunity.