DNA vaccines are safe, easy to manufacture and stable, but they don't always trigger a good enough immune response. Inovio Pharmaceuticals' ($INO) solution to this problem, combining an injection into the skin with a low-current electric pulse, has gotten DNA into skin cells in animal studies, with a good immune response.
The electric pulse disrupts the cell membrane (known as electroporation), letting the DNA into the cell, where it can trigger the immune system. Targeting the skin cells has a number of advantages: The injections are less invasive and painful and the immune response in skin cells is very good and very broad.
As the researchers say in the paper in Human Gene Therapy: "Optimizing electroporation conditions is a balance between increasing expression to drive immunogenicity and inducing inflammation that can negatively impact tolerability." They tried a number of different currents of electric pulse in the animals and found (perhaps surprisingly) that using a lower current electric pulse actually triggered better antibody and T cell responses to an HIV DNA vaccine than a higher current pulse. It also (perhaps less surprisingly) caused lower levels of inflammation in the skin.
These findings could lead to physicians being able to use lower doses of vaccine, cutting the cost and side effects, as well as increasing the number of vaccine targets. This is good news for the company's HIV and flu vaccines, both in Phase I trials. However, it's important to remember that these are still early stage studies.
- read the press release
- see the paper