A vaccine that takes the high out of cocaine for mice could also be useful in treating human addiction, researchers announced Tuesday (Jan. 4).
The vaccine combines a segment of the common cold virus with a molecule similar to cocaine. After receiving the shot, mice dosed with the drug didn't respond with the hyperactive symptoms of a cocaine high, the researchers reported online in the journal Molecular Therapy. The vaccine works by turning the body's immune system against cocaine, preventing the drug from reaching the brain.
"Our very dramatic data shows that we can protect mice against the effects of cocaine, and we think this approach could be very promising in fighting addiction in humans," study researcher Ronald Crystal, a professor of genetic medicine at Weill Cornell Medical College, said in a statement.
The researchers built the vaccine by taking apart an adenovirus, a type of virus responsible for the some cases of the common cold. They discarded the components that cause disease and kept those that alert the immune system to the virus' presence. Next, they hooked the adenovirus parts onto a molecule similar to cocaine. The real thing wasn't used because the cocaine lookalike was more stable and elicited better immunity, Crystal said.
When injected into regular lab mice, the vaccine triggered a strong immune response: anti-cocaine antibodies, or small immune proteins that target invaders. Cocaine usually doesn't elicit an immune response, but the addition of the cold virus parts "trained" the immune system to go after the drug: When isolated in the lab, the antibodies neutralized cocaine, the researchers found.
Next, the researchers dosed the vaccinated mice with cocaine. Despite the drug exposure, the animals didn't get high — an effect that lasted at least 13 weeks.
"While other attempts at producing immunity against cocaine have been tried, this is the first that will likely not require multiple, expensive infusions, and that can move quickly into human trials," Crystal said. "There is currently no FDA (Food and Drug Administration) approved vaccine for any drug addiction."
The drug will have to go through extensive testing in humans to make sure it is safe and effective before it could receive approval from the FDA. However, Crystal said, he suspects the vaccine will work best on cocaine addicts who are trying to quit.
"The vaccine may help them kick the habit, because if they use cocaine, an immune response will destroy the drug before it reaches the brain's pleasure center," Crystal said.
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