• DNA vaccination is a technique for protecting against disease by injection with
genetically engineered DNA (Plasmid DNA) so cells directly produce an antigen,
producing protective immunological response.
• Muscle cells take up the DNA and the encoded protein antigen is expressed, leading
to both a Humoral antibody response and a Cell-mediated response.
• Several DNA vaccinesare available for Veterinary use. Currently no DNA vaccines
have been approved for human use.
• A veterinary protect horses from West Nile virus (ssRNA
• An improved method for administering these vaccines entails coating
microscopic gold beads with the plasmid DNA and then delivering the coated
particles through the skin into the underlying muscle with an air gun (called a
Gene gun). This will allow rapid delivery of a vaccine to large populations
without the requirement for huge supplies of needles and syringes.
• Research of DNA Vaccine is underway for viral, bacterial and parasitic
diseases in humans, as well as for several cancers.
Advantages of DNA Vaccines
• No risk for infection
• Antigen presentation by both MHC molecules
• Ease of development and production
Stability for storage and shipping
• long-term persistence of immunogen
• Encoded protein is expressed in the host in its naturalform there is no
denaturation or modification.
• Refrigeration is not required for the handling and storage of the plasmid
DNA, a feature that greatly lowers the cost and complexity of delivery.
• DNA vaccines also induce both Humoral and Cellmediated immunity.
• DNA vaccines cause prolonged expression of the antigen, which generates
Disadvantages of DNA Vaccines
Limited to protein immunogens (not useful for non-protein based antigens
such as bacterial polysaccharides)
• Risk of affecting genes controlling cell growth
• Possibility of inducing antibody production against DNAPossibility of
tolerance to the antigen (protein) produced
• Potential for atypical processing of bacterial andparasite proteins