US scientists have developed a vaccine which could one day immunise smokers against nicotine addiction.
The 'smoking vaccine' is designed to use the liver as a factory to produce antibodies that attack nicotine the moment it enters the bloodstream, preventing the chemical from reaching the brain and the heart.
In a study on mice, researchers from the Weill Cornell Medical College, in New York, describe how a single dose of their vaccine protects the animal against nicotine addiction.
Professor of genetic medicine, Dr Ronald G Crystal, said: "As far as we can see, the best way to treat chronic nicotine addiction from smoking is to have these Pac-Man-like antibodies on patrol, clearing the blood as needed before nicotine can have any biological effect."
"Our vaccine allows the body to make its own monoclonal antibodies against nicotine, and in that way, develop a workable immunity."
Other smoking vaccines have been developed to produce antibodies that bind to nicotine, but failed in clinical trials because they only produced enough antibodies to last a few weeks and required repeated injections.
Weill Cornell Medical College used a different approach, a genetic vaccine, which Crystal believes is more promising.
"While we have only tested mice to date, we are very hopeful that this kind of vaccine strategy can finally help the millions of smokers who have tried to stop, exhausting all the methods on the market today, but find their nicotine addiction to be strong enough to overcome these current approaches," Crystal added.
Scientists took the genetic sequence of an engineered nicotine antibody, created by co-author Dr Jim D Janda, of The Scripps Research Institute, and put it into a non-harmful adeno-associated virus.
They also included information that directed the vaccine to the liver cells, known as hepatocytes.
The antibody's genetic sequence then inserts itself into the nucleus of hepatocytes and these cells start to churn out a steady stream of the antibodies, along with all the other molecules they make.
Image: Studies show that between 70% and 80% of smokers who try to quit light up again within six months. Image courtesy of: FreeDigitalPhotos.net.