Edible vaccines are plant-based vaccines that are given orally. They were first tested on humans in 1997 using potatoes to deliver vaccines. Since then, many plant species like tobacco, tomatoes, and potatoes have been genetically engineered to produce vaccines for diseases like hepatitis B, cholera, norovirus, and rabies. Recent research has focused on developing edible vaccines for insects like honeybees and livestock like pigs. Advantages are low-cost production and inducing mucosal immunity through oral administration but challenges include variable dosage and immunotolerance.

1. SURBHI SHARMA (17BPH097)

2. INTRODUCTION
 Vaccines are biological solutions or
preparations which provide immunity to a
particular disease.
 Edible Vaccines are transgenic plant and
animal based preparations that contain some
agents which trigger or stimulate an immune
response.
 They are called edible vaccines because the
edible part of plants can be used to get
vaccinated. These vaccines are given orally.

3. HISTORY
 Edible vaccines were first tested on humans in 1997.
The scientists asked volunteers to eat anti-diarrhea
potatoes produced by “Boyce Thomson Institute "at
Cornell University(New york,USA).
 Roswell Park Cancer Institute in Buffalo(New York) also
developed edible vaccines in raw potatoes which helped
to treat hepatitis B virus .Transgenic potatoes produced
both serum and secretory antibodies when fed to mice.
This was the “first proof” in the concept of edible
vaccines.

4. HISTORY
 The first recombinant plant derived pharmaceutical
protein (PDP) was human serum albumin produced in
1990 in transgenic tobacco and potato plants. The co-
workers expressed hepatitis B surface antigen in
tobacco to produce immunological active ingredient.
 Further studies were done and researchers found that
many plants can be used to make edible vaccines with
various pharmaceutical uses. Till date ,work is going on
in the field of edible vaccines.

5. 1990-Hepatitis(tobacco)
1992-Diarrhea(potato)
1995-Rabies(tomato)
1996-Norwalk virus(potato/tobacco)
1996-Cholera(tobacco)

6. Concept of Edible Vaccines
 Hippocrates said “Let thy food be thy medicine",
scientists suggest that plants and plant virus can be
genetically engineered to produce vaccines against
diseases.
 A desired gene in introduced into plant and this altered
plant is then induced to manufacture the encoded
proteins. This process is called “transformation” and the
altered plant is called “transgenic plant". Edible vaccines
are composed of antigenic proteins but devoid of
pathogenic genes.

7. Mechanism Of Action
 After the oral administration of edible vaccine, the
hard outer wall of plant cell which protects them from
gastric secretion breaks in intestine and antigens are
released. This process is called bio-encapsulation .
The antigens in transgenic plants are delivered
through this process.
The M cells in intestinal lining(payer’s patch) take up
these antigens .
They pass onto macrophages and to other antigen
presenting cells.

8. The M cells located in payer's patches are source of
immunoglobin antigens. activate the B cells within the
lymphoid follicles.
After the local lymphocytes activation , serum IgG and IgE
responses,IgA local responses and memory cells will
neutralize the effect of infectious agent by interaction.
Immune response generated which causes active
immune response against disease.

9. Preparation of Edible Vaccines
There are 2 methods :
1 )Biolystic Method(Bombardment technique)
2) Agrobacterium tumefaciens
3) Electroporation
1)BOMBARDMENT TECHNIQUE:
 The DNA sequence is selected and this selected DNA sequence are
precipitated on metal micro particles. Bombardment is done on plant cell with a
gene gun at high speed. The micro particle penetrate the cell wall and release
exogenous DNA inside cell where it integrates into plant genome.
Gene encoding antigen from pathogen is inserted into bacterial vector or
precipitated I onto micro particles.

11. 2)AGROBACTERIUM TUMEFACIEN:
This is a plasmid or vector carrier system.
Agrobacterium tumefaciens is a naturally occurring soil bacterium
which has the ability to enter plants through wounds or scratches. It
has a circular “Ti plasmid” (tumor inducing) which enables it to infect
plant cell, integrate into genome and produce tumor where it can
survive.
This ability of Agrobacterium tumefaciens is used to insert foreign
DNA into plant genome which is called “transformation”
A new plant is regenerated and t-DNA of bacterium is cut and
incorporated in plant cell .

13. 3)ELECTROPORATION:
 Electroporation is the method in
which DNA is inserted into cells. They
are exposed to high voltage electric
pulse which produces pores in the
plasma .
It requires mild activity of enzyme.
Electroporation causes weakening of
cell wall by which entry of DNA into
cytoplasm is prevented.

14. PROS/ADVANTAGES
 Enhance patient compliance especially in
children because of oral administration.
 Eliminate the need of a trained medical
personnel.
 Production is highly efficient and can be easily
scaled up.
 Activate mucosal and systemic immunity.
 Fear of contamination is eliminated as they are
free of toxins or pathogens.
 Good genetic stability and are heat stable.
 Easy to store because refrigeration not
required.
 Cheap and deliver multiple antigens.

15. CONS/DISADVANTAGES
 Development of immunotolerance to vaccine peptide or
proteins.
 Stability of vaccine in fruits is not known.
 Dosage of the vaccines may be variable.
 Consistency of dosage from fruit to fruit ,plant to plant ,
generation to generation is not similar.
 Not convenient for infants.
 Selection of best plant is difficult.
 Certain foods are not eaten raw like potato. Cooking is
done which may weaken the medicine present in it.

16. USES AND EXAMPLES
POTATO
 NORWALK VIRUS : It causes viral gastroentritis,stomach
problems,vomiting,food poisoning etc.19 out of 20 people fed
with edible vaccine of transgenic potato were treated .
Research is going on effect of banana as well as tomato
powder.
 CHOLERA: Transgenic potato with CT-B gene of Vibrio
cholerae were found to be effective . Eating one potato a
week for a month would provide immunity.
HEPATITIS B: First human trials of potato based vaccine
against hepatitis B have showed very good results .Only one
dose of potato built immunity against hepatitis B virus but still
more research is going on.

17. TOMATO
 H I V: Two HIV protein genes were induced successfully into tomatoes .Recently
spinach was also considered to produce immunity against HIV.
 RABIES: Tomato plants expressing rabies antigen induced antibodies in mice.
Tomato plants were transformed and glycoprotein of rabies virus was shown to be
immunogenic.

18. TOBACCO
 MEASLES: Mice fed with tobacco expressing MV-H could attain antibody which
could be five time effective in humans.
 ANTHRAX: Tobacco leaves bombarded with pag gene could express a protein
similar to existing vaccine.
OTHER APPLICATIONS
CANCER THERAPY: Plants can make monoclonical antibodies for cancer
therapy. Soya bean has been genetically engineered to make these antibody.
BIRTH CONTROL: Tobacco has been found to produce antibodies which
prevent fertilization of eggs in mice.

19. RECENT DISCOVERIES

20. Scientists Create Edible Honeybee Vaccine To
Protect Them From Diseases
“The first ever vaccine for insects now
exists. Scientists at University of
Helsinki in Finland hoping to save
honeybee worked on it. This Edible
vaccine protects the bees against
American foulbrood(a bacterial
disease caused by spore-forming
Paenibacillus larvae ssp.Larvae. This
will help to protect the global food
production honeybees.”
- 1st January,2019

21. Scandinavian Researchers Are Developing
An Edible TBE Vaccine
“Tick borne encephalitis (TBE) spreads through
tick’s (ectoparasites) saliva and causes
inflammation of brain. The new edible vaccine
is being developed involving Swedish, Danish
and Norwegian partners to reduce tick related
infections. Scientists hope to be able to begin
animal testing of vaccine in around 6 months.”
-27 October ,2018

22. Mazen Animal Health Advances Edible
Vaccine Development
“A novel maize based edible vaccine was
developed by this biotechnology company .It
showed positive results for Porcine Epidemic
Diarrhea Virus in pigs. This vaccine is also used
to treat Valley Fever. Previously the same
company discovered maize based edible
vaccine for the treatment of valley fever”.
-7th November,2018

23. Natural Compounds Fight Against Zika And
Dengue Virus
“National University Singapore have discovered that many
edible plants contain natural compounds that can protect
us from Zika and Dengue virus. The university said that
many natural compounds can disrupt the replication
machinery of both zika and dengue virus. They are
present in foods like tea, red onion, yellow ginger and
grapes. In future the research team plans to test this
vaccine .”
-5th October,2018