Researchers at the laboratory of California Institute of Technology's Professor Pamela Bjorkman have been researching a possible vaccine to defeat SARS-CoV-2 even before the different variants of the virus became known, according to MIT Technology Review.
Alexander Cohen was a Ph.D. student at Bjorkman's structural biology laboratory at Caltech when they attempted to engineer a "universal" flu vaccine that would fight any strain of the flu virus.
He received his degree in 2020 when COVID-19 started to hit. So together with Bjorkman and other lab members, they set to engineer a universal COVID-19 vaccine that will protect against all of its variants and future illnesses caused by any type of coronaviruses.
How It Works: The Making of the Nanoparticle Vaccine
Cohen and his team understand that the key to engineering the universal vaccine is through the mosaic nanoparticle made of pieces from the spike proteins of SARS-CoV-2, and other SARS-like betacoronaviruses attached to a nanoparticle structure to induce the production of cross-reactive antibodies.
The B cells that generate specific antibodies are likely to bind in some of these pieces of the virus that remain unchanged in new variants and make antibodies that are effective against even previously unseen variants.
In their study, titled "Mosaic RBD nanoparticles protect against challenge by diverse sarbecoviruses in animal models," published in Science, researchers explained how they made their new vaccine known as mosaic-8 nanoparticle.
MIT Technology Review reported that Cohen's team and collaborators chose pieces of spike proteins from the surfaces of 12 coronaviruses identified by other research groups, including the first SARS-CoV, SARS-CoV-2, and a coronavirus found in a pangolin.
All strains have been genetically sequenced and share 68 to 95% similar genomic material, which ensures that at least some portions of each distinct spike protein they place on the exterior of the nanoparticle would be shared by other viruses. They made three vaccines: one with 60 slots occupied by a single strain of SARS-CoV-2, and the two were mosaics with a mix of protein fragments from eight of the 12 coronavirus strains.
Artist Luke Jerram's glass sculpture of the Oxford-AstraZeneca coronavirus vaccine at the Paintworks on February 05, 2021 in Bristol, England. The sculpture, which is one million times larger than the actual vaccine nanoparticle, marks the ten millionth vaccination to be administered in the UK.
They tested all three vaccines in their mouse models and found that all bound equally well to the SARS-CoV-2. However, the mosaic nanoparticles performed more powerfully when exposed to other coronavirus strains that were not presented on the spikes they had been exposed to.
Moreso, they triggered the production of antibodies to attack the parts of the proteins in different coronavirus strains.
New Vaccine May Provide Protection Against Future Strains of SARS-CoV-2
The team then tested the mosaic-8 nanoparticle vaccine on nonhuman primates and compared the effects versus no vaccination in animal studies, Science Daily reported. It showed that those inoculated with mosaic-8 showed little to no detectable infection when exposed to coronaviruses, demonstrating its protective capability for current and future variants of the virus.
In both animal studies, the mosaic-8 nanoparticle vaccine provoked immune reactions in mice and macaques to fight mismatched viral strains. The homotypic SARS-CoV-2 vaccine only protected against SARS-CoV-2, but mosaic-8 showed equal neutralization of not only SARS-CoV-2 but also its variants.
The team concluded that the findings indicate the mosaic-8 nanoparticle vaccine may protect SARS-CoV-2, its current and future variants, and any future coronavirus spillovers.
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