The University of Pennsylvania's Matthew Morrow and David Weiner write in Scientific American that DNA-based drugs and vaccines may finally get their time in the spotlight. The vaccines contain DNA plasmids, and while they made a very weak showing when they were first introduced 10 years ago, Morrow and Weiner write that "improvements to the plasmids and new methods for delivering them have dramatically enhanced their potency." The plasmids enter a host cell, which reads the plasmid's gene and makes the required protein, they say. Once the protein makes its way out of the cell, much like a virus would, immune cells react as they would to an illness, and induce immunity to the actual pathogen. Because the plasmids are made of DNA, they aren't perceived by the body as foreign material, so they can be used over and over again, Morrow and Weiner add. New vaccine delivery systems like transdermal patches are being used to great effect as they get more cells to take up the plasmids, making the vaccines more effective, the authors write. And refinements to the plasmids themselves have made the gene constructs more potent. "The ability to safely deliver genes into cells and get those cells to efficiently manufacture the encoded proteins opens avenues to a host of potential treatments," Morrow and Weiner write. "Dramatic progress in the field over the past decade has brought some of the most creative vaccines and therapeutics yet to clinical testing for human benefit." Several of the vaccines and therapies are now being used in animals or in late-stage human trials.
Dawn of the DNA Drug?
Jul 14, 2010