Vaccines! Definitely a particularly relevant word. How would it make you feel if instead of making an appointment at the closest vaccine location, you had the chance to eat them with your next meal? Something like “Today I think we should order pizza and for dessert let’s take a vaccine against hepatitis B.” Okay, to be honest things are not that simple, but the idea remains the same…
Before we move on, let us first clarify a few concepts.
Genetic Engineering
The techniques by which humans intervene in genetic material constitute Genetic Engineering.
Transgenic plants
Genetic Engineering makes it possible to add new genes directly to the organism. Plants that have undergone genetic modification using Genetic Engineering techniques are called transgenic or genetically modified.
Antigen
Each foreign macromolecule that can induce operant (production of antibodies) from the immune system.
Antibodies
Multifunctional glycoproteins produced by the immune system in response to the presence of a “foreign molecule” in the body, essential for the treatment of infections by microorganisms (our little personal knights!).
So, what is the problem that led to the conception of edible vaccines? The high cost of injecting vaccines combined with the difficulty of maintaining them, mainly because of their sensitivity to heat temperatures, constitutes a vital problem mainly for the citizens of developing countries. At the same time, however of lesser importance, the pain that has been connected to the sting of the needle and trypanophobia (fear of medical procedures involving injections or needles) that possesses certain persons, constitute two more restrictive factors of conventional vaccination that could be exceeded.
The idea
The original idea of edible vaccines emanated from Charles Arntzen, a molecular biologist with specialization in the biology of plants and biotechnology, in the early 90s in an attempt to limit the rates of children’s mortality in economically downgraded regions due to the absence of programs of vaccination.
His vision was based on the creation of transgenic plants that will express antigens, so that the consumption of their products leads to the production of the corresponding antibodies by the body with the ultimate goal of disease prevention. Positive results were observed in animal trials, but also in some human clinical trials performed during the following years. The example of the transgenic potato, in which the surface antigen of the virus of hepatitis B or subunit B of the toxin of enterotoxigenic E. coli, has proven that it caused the expected immunological responses after the (raw) consumption of it.
Do you start viewing fruits and vegetables differently now?
Problems and Restrictions
The more general insecurity of the public towards genetically modified food, the high cost of research, the time-consuming process of approval and mainly the need for further research to determine the appropriate doses of produced antigen and dose of consumption for safety and induction of satisfactory levels of immunization summarize the main obstacles encountered in the product of edible vaccines.
For these reasons, it appears that into practice perhaps it would be more efficient to use plants, releasing us thus from bacterial and animal sources (#crueltyfree), but eventually the product will be processed and given in the form of a pill, as the virologist and immunologist Hilary Koprowski states that “the edible vaccine will have to be given in the form of a capsule, which will include dehydrated leaf extract,” but also Arntzen himself says that “in this case, the achievement of equable doses would be easier, with the extracts coming from potatoes, lettuce, corn, and also tobacco leaves (by the removal of the nicotine and the other alkaloids). We can for example lyophilize the potato, put it in a gelatin capsule and make equable doses of the vaccine.”
In any case, edible vaccines (of any form) could allow the creation of a large number of low-cost stocks, elements that highlight the significance of their possibilities but also the need of a deeper exploration.
So, what do you say? Pancakes or vaccine for breakfast?
REFERENCES:
http://www.sciam.gr/topics.asp?action_id=topic_analysis&issue_id=306&topic_id=507 (περιοδικό Scientific American, Ελληνική έκδοση)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5049623/ (άρθρο του C. Arntzen, US National Library of Medicine National Institutes of Health)
Βιβλίο «iGenetics, Μια Μεντελική Προσέγγιση», Peter J. Russell
Photography by Evelina Papadopoulou
