If you're a smoker who's trying to quit, you may recall hearing about vaccines designed to cause the body's immune system to treat nicotine like a foreign invader, producing antibodies that trap and remove it before it's able to reach receptors in the brain. It's a fascinating idea, but according to scientists at California's Scripps Research Institute, a recent high-profile attempt had a major flaw. They claim to have overcome that problem, and are now developing a vaccine of their own that they believe should be more effective.

There are actually two forms of nicotine, and they're like molecular mirror images of one another. These are known as the left-handed and right-handed versions. Although about 99 percent of the nicotine found in tobacco is the left-handed version, a previous vaccine created by a biopharmaceutical company caused the body to create antibodies against both types.

According to lead scientist Prof. Kim Janda, this was a partial waste of the immune response, causing the vaccine to not be as effective as it could have been. As a result, it only worked on 30 percent of test subjects in clinical trials.

Instead, his team has created a vaccine which causes the body to only produce antibodies that target left-handed nicotine molecules – none of the immune response goes towards making antibodies that won't be needed. In lab tests on rats, the vaccine was found to be 60 percent more effective at producing left-handed-nicotine-targeting antibodies than an alternate version, which was made from a 50-50 mix of both left- and right-handed nicotine derivatives known as haptens.

The scientists are now trying to establish how consistently such a vaccine would work across large populations of users, given the variations in individuals' immune systems. They also note that even if it does work to remove the physiological reward system for smoking, users would still have to deal with smoking-withdrawal symptoms.

A paper on the research was recently published in the Journal of Medicinal Chemistry. Another nicotine vaccine, utilizing some of Janda's materials, is currently being developed at Weill Cornell Medical College.