Edible vaccines involve introducing selected genes into plants to produce antigens. When consumed, the antigens are delivered through the digestive tract to immune cells to produce an immune response. Clinical trials show edible potatoes expressing antigens from ETEC, Norwalk virus, and hepatitis B produced protective antibody levels in participants. Edible vaccines could provide a low-cost, heat-stable, easy to administer option for vaccination programs in developing countries. However, public resistance to genetically modified foods and risks of transgenic contamination limit the future of edible vaccines.

1. EDIBLE VACCINES :
CURRENT STATUS
AND FUTURE
Presented By
Dr. Md. Mahmudul Hasan
M,Phil (Microbiology, P- I)

2. What is Edible Vaccine ?
• Edible Vaccine involves
introduction of selected
desired genes into plant and
then inducing these altered
plants to manufacture the
altered protein.

3. How it acts ?
• Antigen in transgenic plant > Ingestion
>Delivered by bioencapsulation >Taken
up by Mcell > Pass on to the Macrophage
>IgG,IgE responses > Local IgA response
& Memorycells > Neutralize the attack by
the real infectious agent.

4. Advantage and Disadvantage of
different plants
• Potato :
Advantage
Easily transformed.
Easily propagated.
Stored for long periods without refrigeration.
Disadvantage
Need cooking which denature antigen.

5. Advantages and Disadvantages
• Banana
Advantages
Do not need cooking.
Protein not destroyed even after cooking.
Inexpensive .
Grown widely in developing countries.
Disadvantages
Trees take 2-3 to mature years.
Spoils rapidly after ripening.

6. Advantages and Disadvantages
• Rice
Advantages
Commonly used in baby food.
High expression of antigen.
Disadvantages
Grows slowly.
Requires glasshouse condition.

7. Advantages and Disadvantages
• Potato
Advantage
Grow quicly.
Cultivate broadly.
High content Vitamin-A may boost immune
response.
Disadvantages
Spoils readily.

8. Clinical Trial on
ETEC :
11 Volunteers were feed raw transgenic
Potatoes expressing LT-B.
10 (95%) of these individuals developed
neutralizing antibodies and 6
(55%)develop mucosal response.

9. Clinical Trial on
• Norwalk Virus
20 people fed with transgenic potato .
19 (95%)of them expressing Norwalk virus
antigen showed seroconversion.

10. Clinical Trial on
• Hepatitis B
First human trials of potato-based vaccine
against Hepatitis B have reported
encouraging results.
The amount of HBsAg needed for one dose
could be achieved in a single potato.
Levels of specific antibodies significantly
exceeded the protective level of
10mIU/mL in human.

11. Advantages of Edible Vaccine
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Cost effective.
Easy to administer.
Easy to store.
Acceptable to poor developing country.
Fail safe
Activate both mucosal and systemic immunity.
Heat stable.
Do not required cold chain maintenance.
No fear of contamination.

12. Future of Edible Vaccine
• Resistance to GM foods may affect future
of Edible Vaccine.

13. Limitation
• Transgenic contamination can occur.
• Antibiotic resistance marker genes can
spread from GM food to pathogenic
Bacteria.
• Difficulty in dose maintenance.

14. Conclusion
• Edible plant derived vaccine may lead to a
future of safer and more effective
immunization.