What are DNA vaccines ?

Explanation

(i) Genetic immunisation by using DNA vaccines is a noval approach that come into being in 1990. The immune response of the body is stimulated by a DNA molecule.
(ii) A DNA vaccine consists of a gene encoding an antigenic protein, inserted onto a plasmid, and then incorporated into the cells in a target animal.
(iii) DNA instructs the cells to make antigenic molecules which are displaced on its surfaces. This would evoke an antibody response to the free floating antigen secreted by the cells.
The DNA vaccine cannot cause the disease as it contains only copies of a few of its genes, DNA vaccines are relatively easy and inexpensive to design and produce.
(v) Advantages : Producing target proteins , long lasting immunity, trigger immune response only aganist specifc pathogens with lenss toxic effects.
(vi) Recombinant hepatitis B vaccine as a subunit vaccine is produced by cloning hepatitis B surface antigen (HbsAg) gene in the yeast, Saccharomyces cerevisiae.
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