More than 400,000 people in the U.S. and
half of all smokers in Britain die prematurely every
year due to tobacco. A nicotine vaccine that is very
promising for preventing so many deaths will be welcomed
heartily by everyone except Big Tobacco and those who feed
off the tobacco industry's money.
It may also be an effective method for
preventing and treating tobacco addiction, further
eradicating tobacco's hold on people who try smoking only to
find they are unable to quit.
Researchers associated with the Minneapolis
Medical Research Foundation and Hennepin County Medical
Center; the University of Houston-Clear Lake; and Nabi,
a pharmaceutical firm based in Boca Raton, Florida developed
a nicotine vaccine consisting of a nicotine derivative
attached to a large protein, according to findings published
in the December 17 issue of Pharmacology, Biochemistry and
Behavior.
Nicotine is the main addictive component of
tobacco. The purpose of the vaccine is to prevent nicotine
from reaching the brain so as to reduce its effects and help
keep people from becoming addicted.
"A nicotine vaccine may be useful for preventing and
treating tobacco addiction because vaccinated persons would
not be able get a 'kick' from the nicotine in tobacco smoke
or chewing tobacco," says NIDA Director Dr. Alan I.
Leshner. He added that NIDA is also supporting efforts to
produce vaccines directed against cocaine, methamphetamine,
and PCP.
When injected in laboratory animals, the vaccine stimulates
the immune system to produce proteins called antibodies that
bind tightly to nicotine. The antibody-bound nicotine is too
large to enter the brain, thereby preventing nicotine from
producing its effects. The antibody-bound nicotine is
eventually broken down to other harmless molecules.
The scientists injected a single dose of nicotine into
vaccinated rats and found that the amount of nicotine
reaching the brain was reduced by 64%. They were given the
equivalent of the nicotine a human would get from smoking
two cigarettes.
They also administered various doses
of antibodies to the rats and studied how the antibodies
affected nicotine's tendency to raise blood pressure and
stimulate movement. The researchers found that administering
doses of nicotine antibodies similar to those that are
ordinarily produced by the vaccine greatly reduced the rise
in blood pressure produced by a nicotine injection. The
antibodies also completely prevented the increased movements
ordinarily seen when rats are injected with nicotine.
The lead author of the article, Dr. Paul Pentel, says that a
nicotine vaccine should be less likely to produce side
effects than medications that act in the brain to counter
nicotine's effects because the vaccine itself never enters
the brain.
"Nicotine is a particularly good
candidate for a vaccine because it is a very potent drug.
The doses of nicotine that people need to feel its effects
are relatively small, so that the antibodies produced by
vaccination can bind a large fraction of each nicotine
dose," says Dr. Pentel.
Study co-author Dr. David Malin points out that,
"Vaccines can have very long-lasting effects. This may
be helpful because smokers who quit sometimes relapse and
resume smoking weeks or months later."
"We are encouraged by the results obtained so far in
these studies," says Dr. Pentel. The next steps will be
to conduct additional safety studies, followed by clinical
trials with the vaccine in human volunteers beginning in
early 2002.
Frank Stonebanks, a spokesman for Nabi which
is about to commence similar trials, said he foresaw a day
when parents would get their children vaccinated against
smoking in the way that most are inoculated today against
tuberculosis.
"Such drugs would also have huge potential in the
Third World where tobacco addiction costs people a much
bigger proportion of their income," he said.
Related
Resources:
Cigarettes
and Other Nicotine Products 
National Institutes of Health (NIH) report
Pharmacology
Guide report on the Nicotine Vaccine
"No one
ever died from NOT smoking, but the reciprocal is not
true."
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