Vaccine takes joy out of smoking
From JONATHAN LEAKE of The Sunday Times in London
15nov99

IN what could be the last gasp for the tobacco industry, scientists have come up with a vaccine that can block the effects of nicotine for up to a year.

The vaccine will initially be targeted at smokers who want to give up the habit. Although the drug would not take away the nicotine craving, cigarettes would become completely unsatisfying, making it pointless to smoke them.

The drug could also be used to vaccinate youngsters before they even started smoking. Most adults who smoke began the habit while in their teens, so an annual vaccination for those aged 12 to 20 could prevent the industry recruiting new customers.

"The potential for this kind of drug is huge," said John Shields, senior vice-president of research at Cantab, the British developers.

Making such a drug available to the public would be a landmark in the history of vaccines. Until now almost all vaccines have been targeted at micro-organisms such as viruses and bacteria. It would be the first time this sort of approach had been used to alter behaviour on such a potentially large scale.

Vaccination depends on activating the immune system to recognise and destroy an invading organism or molecule. Previous attempts to develop a vaccine against nicotine have foundered because the nicotine molecule was too small to be recognised.

The solution adopted by Cantab and by Nabi, a rival US firm conducting similar research, is to attach the nicotine molecule to a larger one. Cantab's vaccine uses a protein stripped from the toxin produced by cholera bacteria. The protein is known to be safe because it is the basis for the cholera vaccine.

Between one and four nicotine molecules are attached to each protein molecule, making them large enough for the body's defences to recognise as a hostile invader. Once alerted, the immune system starts to make antibodies specifically targeted for nicotine.

They then bind to every nicotine molecule they can find and destroy them. It means hardly any nicotine can pass from the blood into the brain.

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