The coronavirus pandemic is not yet over. As researchers struggle to find full-proof treatment for SARS-CoV-2 and all its variants, a new SARS-CoV-2-like virus capable of infecting humans and resistant to available vaccines has been found in Russian bats. A team led by researchers at Washington State University (WSU), US has found spike proteins from a horseshoe bat virus named Khosta-2. The study describing the findings was published on September 22 in the journal PLOS Pathogens.
What is Khosta-2
A sarbecovirus known as Khosta-2 has been discovered in Russia. It has been shown to interact with the ACE2 receptor, which is similar to the entry receptor for SARS-CoV-2.
Researchers created viral pseudotypes by combining the viruses and foreign envelope proteins. They were then able to produce these particles using a recombinant version of SARS-CoV-2 spike encoding for Khosta-2 Receptor Binding Domain.
Khosta-2 is resistant to existing Covid-19 vaccines
The Khosta-1 and Khosta-2 viruses were identified in Russian bats in late 2020 but they did not appear to be a threat to humans initially, the researchers said.
While Khosta-1 posed a low risk to humans, Khosta-2 appeared to be troubling for humans. There is a potent risk of Khosta-2 recombining with a second virus-like SARS-CoV-2.
The researchers found that the recombinant binding domain produced by Khosta-2 can bind to the human ACE2 receptor, which allows it to enter cells. The viral pseudotypes were also resistant to both the serum from individuals who were vaccinated against SARS-CoV-2 and the human monoclonal antibodies.
The researchers then prepared viral pseudotypes that are similar to the Khosta-2 RBD using a SARS-CoV-2 spike. They were able to find that the spike was resistant to a specific human monoclonal antibody called Bamlanivimab.
The researchers then tested the effects of the SARS-CoV-2 spike on the development of the viral pseudotypes by injecting it into the body of individuals who were given either the Pfizer Covid-19 or Moderna vaccine. The researchers found that the wild-type spike was easily inhibited by the injected serum. However, the SARS-CoV-2 spike that was produced by the researchers was resistant.
The result of the study hold significance as it revealed that the development of new sarbecoviruses could threaten the current vaccines against SARS-CoV-2. The urgent need for the development of more effective and broad-protecting vaccines against this virus is also highlighted by the study.