Protein nanovaccine
The SARS-CoV-2 virus causing the COVID-19 pandemic is just one of many in the coronavirus family. Many of them circulate in animal populations and can "jump" into the human population, as happened with SARS-CoV-2. Researchers are working to develop vaccines for a wide range of related coronaviruses in order to prevent future pandemics.
Alex Cohen's group from the California Institute of Technology has developed a 60-subunit protein-based nanoparticle on which fragments of eight different types of coronavirus were attached. When injected into mice, this vaccine caused the production of antibodies to various coronaviruses, including even those that were not present on the nanoparticle.
The mosaic nanoparticle platform used in the vaccine was previously developed by Oxford University researchers. The nanoparticle has the shape of a cell consisting of 60 identical proteins, each of which has a small protein label that acts as a hook. Cohen and his group used fragments of spike proteins of various coronaviruses (spike proteins play a major role in infection) and designed each of them so that it also had a protein hook that would attach to proteins in the nanoparticle. When these viral parts were mixed together by a nanoparticle resembling a cell in structure, each viral label was attached to it, as a result of which the nanoparticle contained spikes on its surface representing various strains of coronavirus.
The presence of spikes (receptor-binding domains) of eight different coronaviruses caused the production of a variety of antibodies, which is an advantage compared to traditional vaccination methods, which are fragments of only one type of virus. The antibodies that were produced in mice after the introduction of the vaccine were able to respond to many different strains of coronavirus. It is important to note that the antibodies also reacted to coronavirus strains that were not present on the nanoparticle. This suggests that the immune system, having received several different variants of coronavirus with vatsina, learns to recognize common features of coronaviruses and, thus, is potentially able to respond to a newly emerging coronavirus, and not only to the SARS-CoV-2 variant.
Researchers are still studying the mechanism behind this phenomenon, but the results are already encouraging. The next step is to investigate whether immunization prevents viral infection and/or symptoms of infection in animals producing these antibodies.
If the group can show that the immune response caused by the protein nanoparticle vaccine really protects against diseases caused by infection, then it will be able to move this technology forward into human clinical trials.
According to scientists, SARS-CoV-2 is unlikely to be the last pandemic coronavirus. Therefore, a vaccine that forms antibodies against several types of coronavirus, even those that were not presented on the injected nanoparticle, will protect the population. It is also important that the vaccine causes a neutralizing response against SARS-CoV-2, so in case of successful trials it can be used to protect against COVID-19.
Article by A.A.Cohen et al. Mosaic nanoparticles elicit cross-reactive immune responses to zoonotic coronaviruses in mice published in the journal Science.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on Caltech materials: Nanoparticle Immunization Technology Could Protect Against Many Strains of Coronaviruses.