VACCINES AIMED AT HABITS

Research Targets Overeating, Use Of Drugs, Smoking

CHICAGO - Vaccines, the most potent medical weapon ever devised to
vanquish deadly germs, are now being called on to do something
totally different and culturally revolutionary -- inoculate people
against bad habits like overeating, cigarette smoking and drug use.

Whether this new era of vaccine research can subdue many of the poor
lifestyle choices that are today's biggest threats to health --
causing obesity, cancer, heart disease and other problems -- has yet
to be proved.

But the evidence is promising enough to persuade the federal
government to put millions of dollars toward finding out whether two
of the vaccines can end nicotine and cocaine addiction.

The National Institute on Drug Abuse, which has spent $15 million on
clinical trials for the vaccines and plans to spend more, predicts
that one of the nicotine vaccines may be available for marketing in
three years.

Public Health Benefit

"The American Cancer Society has projected that we will have 1
billion people die from smoking in the world in this century," said
Frank Vocci, director of medications development for the institute.
"If you had a vaccine that helped people quit and stay quit, or
prevent them from smoking, that's where you'd get the greatest public
health benefit."

Meanwhile, results from a major obesity vaccine trial under way in
Switzerland are expected this year and company officials are hopeful
that the vaccine could be ready for use in a few years.

To tamp out deleterious behavior, the new vaccines employ the immune
system in an innovative way. Instead of building antibodies to
destroy germs as traditional vaccines do, they construct antibodies
that lock onto nicotine and cocaine molecules, preventing them from
reaching the brain.

"What we're seeing is a renaissance in vaccine technology," said Dr.
Gary Nabel, director of the National Institute of Allergy and
Infectious Diseases' Vaccine Research Center. "It's only natural that
when you have a technology that's this powerful it can be applied to
other medical problems."

Normally, nicotine and cocaine molecules are too small to be seen by
the immune system. So to make the vaccines, scientists attach these
molecules to big target proteins, like harmless viruses or bacteria,
which the immune system can recognize and attack with specialized antibodies.

When the person later smokes a cigarette or takes cocaine, the
antibodies wrap up and neutralize the molecules before they can
trigger euphoria and pleasure in the brain. Smokers and cocaine users
given the vaccines say their pleasure is diminished or they no longer
get as high, which decreases the desire for the drug.

In the case of the obesity vaccine, antibodies attach to the hunger
protein called ghrelin, preventing it from reaching the brain and
stimulating appetite.

Ghrelin, which is secreted by the empty stomach, travels in the
bloodstream to the brain, where it tells a person to eat. But the
hormone, discovered in 1999, also has other important roles, such as
signaling the body to become less active and to store food as fat
instead of using it for energy production.

The reason it can be so hard to lose weight, researchers believe, is
that dieting causes large amounts of ghrelin to be produced as the
body seeks to stimulate eating, slow the metabolism of fat and
promote fat retention.

Society's Major Ills

To many researchers, the vaccines seem to be a potential answer to
many of society's major ills -- in the United States there are 50
million cigarette smokers, 5 million drug addicts, 60 million obese
adults and 9 million overweight youngsters between the ages of 6 and 19.

Most have one thing in common: They'd like to quit but can't. Nearly
seven out of 10 smokers, for instance, say they want to stop, but 80
percent to 90 percent of those who try to quit resume smoking within a year.

Unlike most older vaccines, which tend to confer permanent immunity,
the new breed of vaccines is reversible, providing immunity against
nicotine, cocaine or the hunger hormone ghrelin for one to three
months before booster shots are needed. So far, none of the lifestyle
vaccines has produced side effects other than some flu-like symptoms
and soreness at the injection site.

"These vaccines are not going to be a panacea for treating
everything," said Kim Janda of the Scripps Research Institute, a
pioneer in developing vaccines for addiction and obesity. "I believe
they can be helpful. When people are undergoing abstinence for drugs
of abuse and they have weak moments, if you have a vaccine in place
it can assist them so they don't spiral down to ground zero."