Vaccinations have long had a starring role in preventing a variety of diseases. But now, researchers are aiming the needle at a new set of targets—smoking, obesity, and illicit drugs. These vaccines, currently in development, could give people a novel way to boost their health and vanquish their vices.
Vaccines have been doing their part to eradicate disease since the 18th century, typically by jump-starting the immune system to fight infectious bacteria and viruses such as those that cause the flu, cholera, or tetanus. But in 1974, narcotics researcher C. Robert Schuster, then at the University of Chicago, and his colleagues published the first evidence that vaccines could rev up the immune system against a different type of target—heroin. In a twist on their typical preventive role, these vaccines stop substances from satisfying an already-addicted user’s cravings.
To produce their antiobesity vaccine, the researchers needed a molecule on which to focus the immune system’s antibodies, like the nicotine or cocaine molecules targeted by vaccines against those addictions. But obesity is a complex phenomenon spurred by hundreds of different molecules in the body. Eventually, Janda’s team settled on ghrelin, a hormone that spikes hunger, slows metabolism, encourages fat storage, and shifts food preferences toward diets rich in fat.
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Janda’s group found that rats vaccinated against either of two forms of the hormone called ghrelin 1 and ghrelin 3 gained significantly less weight and had less body fat over the next several months than did rats vaccinated with the placebo, even though all the animals ate the same amount of chow.
