DNA vaccination is a proposed experimental technique for protecting an organism against disease by injecting it with naked DNA to produce an immunological response. Thus far, few experimental trials have evoked a response sufficiently strong enough to protect against disease, and the usefulness of the technique, while tantalizing, remains to be conclusively proven. However, in June 2006 positive results were announced for a bird flu DNA vaccine [1]. Naked DNA is histone-free DNA. Research on the use of naked DNA for vaccines and gene therapy has shown some initial success, but have not yet resulted in any generally available therapy. ... Avian influenza (also known as bird flu) is a type of influenza virulent in birds. ...

Most people have been immunized against some diseases. This has led to a decrease of infections with these diseases in the industrial nations and worldwide. Naturally-occurring cases of smallpox have been totally eliminated. But even though the methods of vaccination have been much improved over the last decades, they still hold several disadvantages. Smallpox (also known by the Latin names Variola or Variola vera) is a highly contagious viral disease unique to humans. ...

Some are based on damaged or destroyed pathogens. If the damage was not completely successful, the vaccination itself can cause the disease it was intended to prevent. Even a "safe" vaccine can cause severe adverse effects. Also, you can only be immunized against a single or a few variants of a disease at the same time. Many of today's vaccines have to be constantly cooled, making transport and storage hard and expensive, especially in warm regions of the earth. A pathogen (literally birth of pain from the Greek παθογένεια) is a biological agent that can cause disease to its host. ... Adverse effect, in medicine, is an abnormal, harmful, undesired and/or unintended side-effect, although not necessarily unexpected, which is obtained as the result of a therapy or other medical intervention, such as drug/chemotherapy, physical therapy, surgery, medical procedure, use of a medical device, etc. ...

DNA vaccination might potentially solve these problems. Instead of taking a damaged pathogen, a single gene from that pathogen is artificially copied and multiplied. That gene is then injected into a muscle. For some unknown reason, muscle cells tend to take up this gene and use it as one of their own genes, making the product the gene describes. The immune system will recognize that product as foreign, and remember it, just like it does in the "classic" vaccination. This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... The immune system is the system of specialized cells and organs that protect an organism from outside biological influences. ...

What is the point of this? First, the gene is made artificially, and can therefore be much more pure than any vaccine made directly from pathogens. Second, it is only one of the many genes necessary for the pathogen to reproduce, like a tire is for a car. That small part is enough for the immune system to recognize its enemy, but not enough to become a danger to the body. Third, several different genes can be mixed and injected simultaneously, making it possible to vaccinate against many variants of a pathogen, or against several different pathogens, at the same time. Finally, the genes are cheap to produce, don't require cooling, and can be stored for years.

Today, DNA vaccination is still an experimental procedure. Some DNA vaccines have been tested on humans and proven to be harmless. Only recently, as of May 2006, has the immunizing effect been shown to be of practical use.

From Simple Science Wiki

See also

• Vector DNA
• HIV vaccine

A Vector DNA is a small piece of DNA containing regulatory and coding sequences of interest. ... An HIV vaccine is a hypothetical vaccine against HIV, the etiological agent of AIDS. As there is no known cure for AIDS, the search for a vaccine has become part of the struggle against the disease. ...

External links

• PowderMed pdf report
• DyNAVacS, an Integrative Tool for Optimised DNA Vaccine Design from the Institute of Genomics and Integrative Biology.