Edible vaccines
Selected genes are introduced in to the plants and the transgenic plants are induced to manufacture the encoded protein. Edible vaccines for the measles, cholera, hepatitis B and many more are in the progress of development.
Advantages
•Administration
•Heat stable, eliminates need for refrigeration
•Storage near the site of use
•Delivery of multiple antigens
•Systemic and mucosal immunity
•Free from pathogens and toxins
Preparation
Foreign DNA can be introduced into plant genome either by bombarding embryonic suspension using gene gun or through Agrobacterium tumefaciens. Each antigen expressed is tested by Western blot assay.
Mechanism of action
The antigens in the transgenic plants are delivered through bio-encapsulation. The antigens are released in the intestines and taken up by M cells that overlie payer’s patches and gut associated lymphoid tissue (GALT). Which upon reaching macrophages, generates serum Ig G, IgE, IgA responses which would neutralize the attack of real infectious agents.