A recently discovered virus in a Russian bat, similar to SARS-CoV-2, the virus behind COVID-19, is likely capable of infecting humans and, if it spreads, is resistant to current vaccines.
A team led by researchers from Washington State University’s Paul G. Allen School for Global Health found that spike proteins from the bat virus called Khosta-2 can infect human cells and respond to both monoclonal antibodies and human serum are resistant who have been vaccinated against SARS. CoV-2. Both Khosta-2 and SARS-CoV-2 belong to the same subcategory of coronaviruses known as sarbecoviruses.
“Our research further shows that sarbecoviruses circulating in wildlife outside of Asia – even in places like western Russia where the Khosta-2 virus has been found – also pose a threat to global health and ongoing vaccination campaigns against SARS-CoV-2.” , said Michael Letko, WSU virologist and corresponding author of the study published in the journal PLoS pathogen.
Letko said the discovery of Khosta-2 highlights the need to develop universal vaccines to protect against sarbecoviruses in general, and not just known variants of SARS-CoV-2.
“Right now there are groups trying to develop a vaccine that not only protects against the next variant of SARS-2, but actually protects us from the sarbecoviruses in general,” Letko said. “Unfortunately, many of our current vaccines target specific viruses that we know infect human cells or that pose the greatest risk of infecting us. But this list is constantly changing. We need to expand the design of these vaccines to protect against all sarbecoviruses.”
Although hundreds of sarbecoviruses have been discovered in recent years, mostly in bats in Asia, most are unable to infect human cells. The Khosta-1 and Khosta-2 viruses were discovered in Russian bats in late 2020 and it initially appeared that they posed no threat to humans.
“Genetically, these strange Russian viruses looked like some of the others that had been discovered elsewhere in the world, but because they didn’t look like SARS-CoV-2, no one thought they were really something to get too excited about.” could,” Letko said. “But when we took a closer look at them, we were really surprised that they could infect human cells. That changes a bit our understanding of these viruses, where they come from and which regions are affected.”
Letko worked with two WSU faculty members, first author viral ecologist Stephanie Seifert and viral immunologist Bonnie Gunn, to study the two newly discovered viruses. They found that Khosta-1 posed a low risk to humans, but Khosta-2 displayed some troubling properties.
The team found that like SARS-CoV-2, Khosta-2 can use its spike protein to infect cells by binding to a receptor protein called angiotensin converting enzyme 2 (ACE2), which is found in all human cells . Next, they set out to determine whether current vaccines protect against the new virus.
Using serum derived from human populations vaccinated against COVID-19, the team found that Khosta-2 was not neutralized by current vaccines. They also tested serum from people infected with the Omicron variant, but the antibodies were also ineffective.
Fortunately, Letko said the new virus lacks some of the genes thought to be involved in human pathogenesis. However, there is a risk that Khosta-2 will recombine with a second virus such as SARS-CoV-2.
“When you see that SARS-2 has this ability to flow back out of humans and into wildlife, and then there are other viruses like Khosta-2 that are waiting in these animals with these properties that we really don’t want, it sets that gang scenario where you keep rolling the dice until they combine into a potentially riskier virus,” Letko said.
Co-authors of this study include Letko, Seifert and Gunn Shuangyi Bai and Stephen Fawcett from WSU and Elizabeth Norton, Kevin Zwezdaryk and James Robinson from Tulane University.
Materials provided by Washington State University. Originally written by Devin Rokyta. Note: Content can be edited for style and length.