Edible Vaccine Short Notes | Biotechnology

In this article we will discuss about Edible Vaccines:- 1. What is Edible Vaccine? 2. Method of Developing an Edible Vaccine 3. Plants used for edible vaccine 4. Applications of Edible Vaccines and 5. Advantages of Edible Vaccines

1. What is Edible Vaccine?

A protein which acts as the vaccine, present in food and consumed as the internal composition of food is known as EDIBLE VACCINE. Edible Vaccine involves introduction of selected desired genes into plant and then inducing these altered plants to manufacture the altered protein.

2. Method of Developing an Edible Vaccine:

Gene encoding antigen from pathogenic organ­isms (virus, bacteria or parasites) that have been characterized and for which antibodies are available, can be produced in the edible parts of the plants in two ways. In one case, the entire structural gene is inserted into a plant transformation vector.

This will allow transcription and accumulation of coding se­quence in plant. In second case, epitope within the antigen are identified, DNA fragment en­coding these can be used to construct genes by fusion with a coat protein gene from plant vi­rus, e.g., TMV or CMV. The recombinant vi­rus is then used to infect stabilized plants. The resultant edible plant vaccines are utilized for further immunological studies.

3. Plants used for edible vaccine:

i) Banana:

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

ii) Rice

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

iii) Potato:

• Advantage Grow quickly.
• Cultivate broadly.
• High content Vitamin-A may boost immune response.

4. Applications of Edible Vaccines:

(a) Malaria:

Malaria remains one of the most significant causes of human morbidity and mortality worldwide, with 300 to 500 mil­lion new cases of infection annually result­ing in 1.5 to 2.7 million deaths. Three an­tigens are currently being investigated for the development of a plant-based malaria vaccine, merozoite surface protein (MSP) 4 and MSP 5 from Plasmodium falcipa­rum, and MSP 4/5 from P. yoelli.

(b) Hepatitis B:

The hepatitis B virus is estimated to have infected 400 million people throughout the globe, making it one of the most common human pathogens. The hepatitis B surface antigen (HbsAg) is used as a vaccine against Hepatitis B.

The HbsAg subtype ayw was cloned into CaMv plasmid and the regenerated plants from the transformed cells were shown to pro­duce HbsAg. Furthermore, expression of the antigen was found to be higher in roots of the transgenic potato than in leaf tis­sues.

(c) Measles:

Measles is a highly contagious viral disease caused by the Paramyxo virus spread by air and includes symptoms such as high fever, skin rash and spots. Each year, almost one million children die from the measles and many of the survi­vors are weakened by pneumonia or en­cephalitis or become deaf.

Recent studies report expression of the Paramyxo virus surface protein haemagglutinin in tobacco, potato, rice and lettuce with satisfying re­sults.

(d) Stopping Autoimmunity:

In the past 15 years, investigators have identified several cell proteins that can elicit autoimmunity in people predisposed to Type I diabetes. The development of plant based diabetes vaccine in potato was attempted.

The de­velopment of transgenic potato and tobacco plants when fed to non-obese diabetic mice showed increased levels of IgG, an anti­body associated with cytokines that sup­press harmful immune response. Feeding of the vaccines to mouse strain that becomes diabetic helped to suppress the au­toimmune attack and to prevent the delay of high blood sugar.

5. Advantages of Edible Vaccines:

Potential advantages of plant-based vaccines are:

• DO not require administration by injection. 
• Possible production of vaccines with low costs. 
• Do not require separation and purification of vaccines from plant materials. 
• Necessary syringe & needles not required. 
• Economical in mass production and transportation. 
• Heat stable, eliminating the need for refrigeration.