Programmable RNA Vaccines Fight Against Influenza, Ebola In Mice
A novel type of modifiable vaccine developed by engineers from Massachusetts Institute of Technology (MIT) has been found to work efficiently against influenza, Ebola and other parasites in mice.
The team's nano-formulation approach allows them to create the vaccine in just seven days, says Associate Professor Daniel Anderson, senior author of the study's paper.
This means that the new vaccine can be quickly deployed in response to disease outbreaks and can be rapidly improved and modified in case it is needed.
Why Programmable RNA Vaccines Are Preferable
Conventional vaccines contain an inactivated form of a pathogen or a virus. These kinds of vaccines typically take a longer time to manufacture, and for some types of diseases, the time gap is too risky.
Other vaccines are also made up of proteins normally produced by the microbe, but experts say these do not usually induce a strong immune response. This often requires scientists to seek an adjuvant or a chemical that enhances the response.
Now, MIT's vaccine takes advantage of a different process. The vaccine contains strands of messenger RNA, which can be manipulated to code for any bacterial, viral or parasitic protein. The molecules are then added into a molecule that takes the RNA to the cells, where it is converted into proteins that trigger an immune response from the host.
Scientists say RNA vaccines are ideal because they trigger host cells to create as many copies of the proteins they encode. In turn, this incites a more effective immune reaction compared with other methods.
Although the idea of using RNA molecules as vaccines has been discussed for decades, one of the obstacles in doing so is finding an effective and safe way to deliver them.
Omar Khan, Anderson's co-researcher on the project, opted to package the RNA vaccines into a nanoparticle from a dendrimer, a branched molecule. An advantage to this material is that scientists can give it a temporary positive charge that makes it form close bonds with the negatively charged RNA.
Khan also found a way to control the pattern and size of the final structure. He induced the structure to fold over itself repeatedly. It produced vaccine particles that were spherical in shape and each had a diameter of 150 nanometers. This size matches that of the virus, enabling the miniscule vaccine particles to enter cells by exploiting the surface proteins.
Details Of The Mice Study
Khan and Anderson believe that by customizing the RNA sequences, experts can design vaccines that can produce nearly any protein they intend it to.
The vaccine can be easily administered by intramuscular injection. Once the vaccine particles target the cells, the RNA is translated into proteins that stimulate the immune system.
In animal studies, mice received a single dose of the vaccine. Researchers found that the mice did not show any symptoms of their exposure to H1N1 Influenza, Ebola or Toxoplasma gondii. Indeed, the vaccine was 100 percent effective in mice.
"We are all excited about the potential of this new approach to provide a new way of vaccine delivery," says study author Robert Langer.
Details of the study will be published in the journal PNAS.
Photo: Carlos Reusser Monsalvez | Flickr