Edible Vaccines

 

 

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Image Permission Granted – (Children With Diabetes)

 

 

Vaccine Production Economic Dilemma

 

Vaccines have been used for years to help inoculate the human population against a variety of diseases.  Gradually the field has developed new vaccines to add to the list of diseases that we can be inoculated against, but this development has resulted in increased costs and supplies for the creation of these vaccines.  The use of animal cells or yeast coupled with facility requirements for refrigeration and other factors is very costly (Langridge 2000).  These production costs result in expensive vaccines which have to be paid by the patient needing the vaccination.  Moreover, the creation of subunit vaccines leads to an increased demand for proper refrigeration and storage for the newly discovered vaccines (Langridge 2000). 

 

Global Problem

 

Not only are these vaccines way too expensive for children in third-world countries, but these countries do not have adequate health care systems for the storage or administration of these vaccines.  Currently 20% of the world’s infants do not receive proper immunizations which lead to 2,000,000 unnecessary deaths each year (Langridge 2000).  The production of edible vaccines creates the potential to use native foods in these third-world countries to be used as vectors for the vaccines.  This explains why bananas, rice, corn, wheat, and soy lead the pack in edible vaccines. 

 

Advantage of Edible Vaccines Over Traditional Vaccination

 

The cost of producing edible vaccines will be as much as 10 to 50 times lower as compared to traditional vaccine production (Giddings, G. et al 2000).  Another more obvious advantage is that syringes will not be required, which allows vaccinations to be less painful and more importantly reduces the risk of transmission of infectious diseases which run rampant through most third-world countries.  Instead, the vaccines can be delivered by food products like bananas which can be eaten raw and served in a puree form (Langridge 2000). 

 

Subunit Preparation Vaccines

 

Traditional vaccine production used a weakened form of the actual virus that a person is being inoculated against to induce the person’s immune system to produce the proper antibodies against this weakened strain and therefore creating immunity.  The only problem with this methodology is that there is a slight risk that the organism will actually not be weakened enough and will infect the vaccinated person.  A new advance in technology known as subunit preparations use the antigenic proteins produced from a pathogen’s genetic material (Langridge 2000).  The advantage of these subunit preparations is that there is absolutely no way the proteins would be able to reform into an infectious organism (Langridge 2000).  Anytime you produce a “better” method you typically encounter a greater cost, which is the case with these subunit preparations.

 

Successful Animal Testing

 

Transmissible Gastroenteritis Virus (TGEV) is a disease which affects pigs (Giddings, G. et. al 2000).  Scientists at ProdiGene were able to insert the vaccine for this virus into the corn eaten by the pigs, and they discovered that the pigs in fact were inoculated for TGEV by the genetically altered corn (Giddings, G. et. al 2000).  This animal test creates a powerful argument that edible vaccines do work and have a lot of potential for future vaccination means.

 

Current Research

 

Currently, a lot research has been focused on using edible vaccines to inoculate against hepatitis B which affects the liver.  Charles Arntzen from Arizona State University has been experimenting with the creation of a potato that carries the hepatitis B surface antigen to inoculate a human against hepatitis B (Dye 2001).  Arntzen is also responsible for the first small-scale clinical trial of edible vaccines on humans in which he found that 95% of the patients he administered a raw potato carrying a subunit vaccination for E. coli exhibited mucosal and systemic immune responses (Langridge 2000).  Arntzen began this process using tobacco and then moved on to food like tomatoes and then potatoes, and he eventually hopes to create bananas capable of inoculation (Charles Arntzen:  Edible Immunity 2002).  Potatoes are also being currently investigated to serve as a vaccination vector against human papilloma virus (HPV) which causes cervical cancer (Potato to Prevent Cervical Cancer 2002).

 

For most of these vaccines or subunit vaccinations, bananas seem to be the desired vector.  The advantage of bananas is that they can be eaten raw as compared to potatoes or rice that need to be cooked [typically], and bananas can also be consumed in a puree form (Langridge 2000).  Research is leaning towards the use of bananas as the vector since most third-world countries, who would benefit most from edible vaccines, are in tropical climates that are suitable for growing bananas.  Scientists have also discovered that fruits with high water content could result in proteolysis (Giddings, G. et. al 2000).  Experimentation with freeze-dried food to create pellets or powder is now being investigated to help avoid proteolysis and overall efficacy (Bonetta 2002).

 

 

 

 

 

 

This webpage was created by David Shelburne ’04 & Paul Toran ’03 as an assignment for an

undergraduate course—Bio 361: Genetically Modified Organisms—at Davidson College.

 

© Copyright 2002 Department of Biology, Davidson College, Davidson, NC 28035

Send comments, questions, and suggestions to: dashelburne@davidson.edu and/or patoran@davidson.edu