DNA vaccines are third generation vaccines, made up of small, circular pieces of bacterial DNA, plasmids. These plasmids are genetically engineered to produce specific antigens from a pathogen.
The DNA is injected into the cells of the body where the host cell then interprets the DNA and uses it to synthesize the pathogen’s proteins. An immune response is then triggered when the pathogen’s proteins are recognized as foreign to the immune system.
Some DNA vaccines were developed from “failed” gene therapy experiments. For example, the first demonstration of a plasmid-induced immune response was when mice injected with a plasmid expressing human growth hormone elicited antibodies instead of showing growth alteration.
What are the Advantages?
DNA vaccines have a number of advantages over conventional vaccines, including the ability to induce a wider range of immune response types and more:
- DNA vaccines are effective in stimulating antibody responses to attack infectious diseases as they enter the body, before they can infect cells, therefore acting as a preventive vaccine.
- DNA vaccines are efficient at generating T-cell responses that may kill targeted cancerous cells or cells infected by the targeted virus or bacteria. DNA vaccines may therefore also be used as a therapeutic to treat existing disease. This capability provides the potential to treat chronic infectious diseases such as HIV and hepatitis C virus, as well as the possibility to develop therapeutic cancer vaccines.
- DNA vaccine technology provides the opportunity to design sophisticated, multi-antigen vaccines and/or vaccines based on conserved genes and antigens that are common to evolved strains of a pathogen, e.g. the potential exists to develop a universal influenza vaccine to protect against both seasonal influenza strains as well as new influenza strains that cannot be known in advance and which present pandemic risk, such as new strains of avian influenza or the Mexican H1N1 influenza.
- DNA sequences from multiple strains of a virus like influenza can also be designed in a “xanax bars online xanaxbars.net” form where one antigen is able to confer protection against any one of the original viral strains.
- DNA vaccines can potentially be developed from concept to FDA approval in eight to 10 years, rather than as much as 20 years that it took to develop, for example, the chickenpox vaccine.
- They can be readily and cost effectively manufactured using off-the-shelf, well-proven fermentation technology.
What are the Disadvantages? One of the issues of most concern to researchers is the possibility that the injected DNA will actually integrate into one of the human chromosomes inside the cell. The effect could range from no effect or could potentially lead to cancer through alteration of cheap modafinil. Other disadvantages to DNA vaccines include:
- Limited to protein immunogens.
- Risk of affecting genes controlling cell growth.
- Possibility of inducing antibody production against DNA.
- Possibility of tolerance to the antigen (protein) produced.
- Potential for atypical processing of bacterial and parasite proteins.
Current DNA vaccines Currently only two DNA vaccines (i.e., Apex–IHN and Oncept) and one DNA therapy (i.e., LifeTide) are currently on the market, all for veterinary applications. Despite this slow start, DNA vaccine research is progressing steadily, and the approval of a human DNA vaccine in the next few years would be a groundbreaking achievement for the sector.
 Information provided by Harriet L Robinson and Tamera M Pertmer