A new vaccine against nicotine addiction
The vaccine, developed by Cornell University scientists, turns the liver of mice into a factory for the production of antibodies that bind nicotine immediately after it enters the bloodstream, preventing its penetration into the brain and heart.
Traditional vaccines are divided into two types: active and passive. Active vaccines are used to prevent polio, mumps, tuberculosis and other infectious diseases. The active ingredient of such vaccines is a fragment of the pathogen recognized by the immune system (a viral particle or a bacterium). The resulting specific antibodies provide a vaccinated person with long-term immunity. Nicotine is a small molecule and is not recognized by the immune system, so the creation of an active anti-nicotine vaccine is technically impossible.
Vaccines of the second type – passive – are used for direct delivery of specific antibodies to the body. Such vaccines include therapeutic antitumor vaccines – antibodies that bind, for example, to growth factors on the surface of breast cancer cells, after which the labeled cells are destroyed by the patient's immune system.
According to the head of the study, Dr. Ronald G. Crystal, clinical studies of earlier versions of anti-nicotine vaccines did not bring positive results due to the fact that their action was based on the direct administration of antibodies that remained in the body for no more than a few weeks. This necessitated the need for regular expensive injections. Moreover, such an impractical "passive" approach to vaccination led to unstable results, possibly due to the need for individual dose selection for each patient, especially in cases of smoking resumption after the first attempt to get rid of a bad habit.
Therefore, the researchers decided to go the other way and developed a third type of vaccine – gene therapy. Initially, they tested a new type of vaccine on mouse models with eye diseases and various types of cancer.
To create an anti-nicotine vaccine, they took the genetic sequence of an artificially synthesized antibody to nicotine, created by Dr. Jim D. Janda from the Scripps Research Institute, and embedded it in a neutralized adenoassociated virus. They also encrypted information in the viral DNA that ensures the selective introduction of viral particles into hepatocytes.
After the introduction of such a vaccine, the liver of animals began to produce a stable amount of antibodies. It also turned out that a small amount of nicotine still reached the brain of vaccinated animals. However, despite this, animal reaction testing showed that the behavior of mice injected with both nicotine and the vaccine did not change, they continued to behave actively. At the same time, mice injected with nicotine alone showed a normal reaction to this compound – they "relaxed", and their blood pressure and cardiac activity decreased, which indicated the direct effect of nicotine on the brain and circulatory system.
The developers plan to test their vaccine on mice and primates, after which, if positive results are obtained, it will be possible to plan clinical trials.
Maybe if the vaccine turns out to be effective and safe for humans, someday it will be included in national vaccination plans?
Article by Martin J. Hicks et al. AAV-Directed Persistent Expression of a Gene Encoding Anti-Nicotine Antibody for Smoking Cessationis published in the journal Science Translational Medicine.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on ScienceDaily: New Vaccine for Nicotine Addiction.
29.06.2012