28 June 2012
Nicotine vaccine mooted for children
by Will Parker
A novel genetic vaccine that modifies the liver to produce antibodies to clear nicotine from the bloodstream could be administered to children in much the same way that polio and HPV vaccines are, say the developers. The team that created the vaccine, from Weill Cornell Medical College, describe their work in the latest issue of Science Translational Medicine. In the article, they describe how a single dose of the vaccine protects mice, over their lifetime, against nicotine addiction.
The vaccine is designed to use the liver as a factory to continuously produce antibodies that nullify nicotine the moment it enters the bloodstream, preventing the chemical from reaching the brain.
"As far as we can see, the best way to treat chronic nicotine addiction from smoking is to have these Pacman-like antibodies on patrol, clearing the blood as needed before nicotine can have any biological effect," says the study's lead investigator, Dr. Ronald G. Crystal, professor of Genetic Medicine at Weill Cornell Medical College. "Our vaccine allows the body to make its own monoclonal antibodies against nicotine, and in that way, develop a workable immunity."
In the past, nicotine vaccines have failed in clinical trials because they worked by directly delivering nicotine antibodies, which only last a few weeks and require repeated injections.
The Weill Cornell team's approach, however, uses a genetic vaccine based on an engineered nicotine antibody and an adeno-associated virus. They also included genetic information that directed the vaccine to go to hepatocytes (liver cells). The antibody's genetic sequence then inserts itself into the nucleus of hepatocytes, and these cells start to manufacture a steady stream of the antibodies. In mice, the vaccine produced high levels of the antibody continuously, which the researchers measured in the blood. They also discovered that little of the nicotine they administered to these mice reached the brain.
The researchers are preparing to test their nicotine vaccine in rats and then in primates - steps needed before it can be tested in humans. Crystal believes it might be possible, given the complete safety of the vaccine, to use it to pre-empt nicotine addiction in individuals who have never smoked. "Just as parents decide to give their children an HPV vaccine, they might decide to use a nicotine vaccine. But that is only theoretically an option at this point," Crystal says. "Smoking affects a huge number of people worldwide... this novel vaccine may offer a much-needed solution."
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Source: Weill Cornell Medical College