Chimeric Spike Proteins
© CoronavirusAlissa Eckert, MS; Dan Higgins, MAMPublic Health Image Library (PHIL) #23312 Centers for Disease Control and Prevention
A new universal vaccine against coronaviruses offers broad protection. This could prevent further pandemics in the future.
Chapel Hill (U.S.A.). All current Vaccines against that Coronavirus SARS-CoV-2 are based on a specific surface structure, the so-called spike protein, which the virus uses to enter human cells, but which also serves as a distinguishing feature for the immune system. In medicine there is therefore a fear that mutations in the virus can lead to changes in the spike protein, which could mean that all previous vaccinations could be less effective.
Scientist the University of North Carolina have now developed a universal vaccine that should not only work against SARS-CoV-2 and its mutations, but also against future coronaviruses. According to David Martinez’s team, this could prevent future pandemics, for which coronaviruses are the greatest risk candidates.
Basic principle as with current mRNA vaccines
The basic principle of the new universal vaccine is identical to the already approved mRNA vaccines from Pfizer / BioNTech and Moderna, which contain a genetic blueprint for the spike protein and thus trigger a process in the cells in which the immune system produces appropriate antibodies.
Instead of just a blueprint for a specific spike protein, the universal vaccine contains chimeric spike proteins, i.e. a combination of spike proteins from different coronaviruses. One of these chimeras contains, for example, components of the spike proteins from SARS-CoV-2, the trigger of the Covid-19 pandemic, as well as SARS-CoV, which triggered the first SARS pandemic in 2003, and a coronavirus, which so far only affects bats occurs, but could skip to humans in the future.
High effectiveness in animal experiments
In an animal experiment, the scientists tested their approach using mice that were vaccinated with a combination of four different chimeric blueprints. Instead, the control groups received a vaccination against noroviruses or an mRNA vaccine, which instead of the chimeric blueprints only contained the blueprint for the SARS-CoV-2 spike protein.
The mice that received the new combination vaccine produced antibodies against both the bat variant and against SARS-CoV and SARS-CoV-2. Therefore, they did not become ill after the scientists denied them after the immunization was complete Viruses expose. There was also no damage to the lung tissue or other organs.
In the mice that were only vaccinated against SARS-CoV-2, however, infections with SARS-CoV occurred. The South African variant of SARS-CoV-2 was also able to infect some of these animals, while such infections did not occur with the combination vaccine. The control group, which was vaccinated with noroviruses, developed infections with all coronavirus variants.
Universal vaccine can prevent pandemic
“The vaccine has the potential to prevent outbreaks if used as soon as a new variant is discovered,” explains Ralph Baric. The current results thus show that the approach of the chimeric spike proteins could in principle be used. If further animal experiments are also successful, clinical studies on humans could be carried out in the near future.
“Our results look promising for the future because they suggest that we can design more universal pan-coronavirus vaccines to proactively protect against viruses that we know are at risk to occur in humans. With this strategy we may be able to prevent SARS-CoV-3, “states Martinez.