Monkeys, Mice Reveal Effective Protection of Nanoparticle Vaccine Against Several SARS-Like Betacoronaviruses

A new vaccine type offers protection against a variety of SARS-like betacoronaviruses, including SARS-CoV-2 in monkeys and mice, a recent study.

A EurekAlert! report specified that according to the study, led by researchers in the laboratory of Caltech's Bjorkman, the David Baltimore Professor of Biology and Bioengineering, betacoronavirus which include those that caused SARS, MERS, and COVID-19 pandemics, are a subset of coronaviruses infecting both animals and humans.

Essentially, the vaccine works by presenting the immune system with pieces of the spike proteins from SARS-CoV-2 and seven other betacoronaviruses similar to SARS, attached to a protein nanoparticle construction to induce the generation of a broad spectrum of cross-reactive antibodies.

Remarkably, when vaccinated with the so-called mosaic nanoparticle, animal models were shielded from an additional coronavirus, SARS-CoV, that was not one of the eight denoted on the nanoparticle vaccine.

SARS-Like Betacoronaviruses

Caltech postdoctoral scholar Alexander Cohen, Ph.D. and co-first author on the study, said animals that have been vaccinated with the mosaic-8 nanoparticles elicited antibodies that recognized virtually each SARS-like betacoronavirus strain they examined.

The co-first author added some of the viruses could be associated with the strain causing the subsequent SARS-like betacoronavirus outbreak. Thus, what they want would be something targeting this entry group of viruses. "We believe we have that," he elaborated.

Bjorkman also explained that SARS-CoV-2 has proven to make new variants that could prolong the worldwide COVID-19 pandemic. Bjorkman is also a professor at Merkin Institute and executive officer for Biology and Biological Engineering.

Additionally, a related ScienceDaily report said that three coronaviruses, including SARS-CoV, MERS-CoV, and SARA-CoV-2, have spilled over into human beings from animal hosts in the last two decades, demonstrating the need for making broadly protective vaccines.

Vaccine Technology

Collaborators initially developed the vaccine technology to bind pieces of a virus to protein nanoparticles at the University of Oxford.

The technology's basis is a small cage-like structure, a nanoparticle, made up of proteins engineered to have "sticky" attachments on its surface, upon which scientists can fasten tagged viral proteins.

These nanoparticles can be prepared to show only pieces of a single virus, known as "homotypic nanoparticles, " or pieces of many different viruses or "mosaic nanoparticles."

When injected into an animal, the nanoparticle vaccine exhibits the viral fragments to the immune system.

This induces the production of immune system proteins called antibodies, which recognize and fight off specific proteins and cellular immune responses that involve T lymphocytes and innate immune cells.

Receptor-Binding Domains

In this research, published in the Science journal, the study authors opted for eight different betacoronaviruses similar to SARS which include SARS-CoV-2, the virus that has caused this present pandemic, along with seven animal-related diseases that could have the potential to begin a pandemic in humans, and connected fragments from those eight viruses onto the nanoparticle scaffold.

The team opted for specific fragments of viral structure, also known as "receptor-binding domains" or RBDs, that are crucial for coronaviruses to enter human cells. In fact, human antibodies that neutralize coronaviruses mainly target the RBDs of the virus.

Related information about nanoparticle vaccine is shown on Nano Tube's YouTube video below:

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