Presented By Dr. Md. Mahmudul Hasan

M,Phil (Microbiology, P- I)

EDIBLE VACCINES :

CURRENT STATUS

AND FUTURE

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.

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.

Advantage and Disadvantage of different plants

• Potato :

Advantage

Easily transformed.

Easily propagated.

Stored for long periods without refrigeration.

Disadvantage

Need cooking which denature antigen.

Advantages and Disadvantages

• BananaAdvantagesDo not need cooking.Protein not destroyed even after cooking.Inexpensive .Grown widely in developing countries.

DisadvantagesTrees take 2-3 to mature years.Spoils rapidly after ripening.

Advantages and Disadvantages

• RiceAdvantagesCommonly used in baby food.High expression of antigen.

DisadvantagesGrows slowly.Requires glasshouse condition.

Advantages and Disadvantages

• PotatoAdvantageGrow quicly.Cultivate broadly.High content Vitamin-A may boost immune

response.DisadvantagesSpoils readily.

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.

Clinical Trial on

• Norwalk Virus

20 people fed with transgenic potato .

19 (95%)of them expressing Norwalk virus antigen showed seroconversion.

Clinical Trial on

• Hepatitis BFirst 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.

Advantages of Edible Vaccine

• 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.

Future of Edible Vaccine

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

Limitation

• Transgenic contamination can occur.

• Antibiotic resistance marker genes can spread from GM food to pathogenic Bacteria.

• Difficulty in dose maintenance.

Conclusion

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