In view of the pandemic, researchers around the world are searching even more intensively for new pathogens. Bats in Russia carry a potential candidate. This can not only penetrate human cells, but even prevails in the laboratory against antibodies and corona vaccines.
Researchers at Washington State University have examined two new types of corona viruses for their dangerousness and discovered a new possible disease trigger for humans. The two coronaviruses found in bats from Russia have been given the names Khosta-1 and Khosta-2. Both, like Sars-CoV-2, belong to the subgenus of the so-called sarbecoviruses.
In a first step, so-called pseudoviruses were generated in the laboratory. These were used to test whether the Khosta-1 and Khosta-2 binding sites on the spike protein could infect human cells. To their surprise, the team found that Khosta-2 is quite capable of this. Because it has the ability to dock to the receptor protein ACE2, which is found on all human cells. Just like Sars-CoV-2 does. "This binding site is around 60 percent comparable to different variants of Sars-CoV-2," reports Seifert and her colleagues in the journal PLOS Pathogens. With Khosta-1, on the other hand, the research team saw only a low risk for humans.
In a next step, it was examined how Khosta-2 behaves both with monoclonal antibodies that develop in the body after an infection and with serum from people who have been vaccinated against Covid-19. Khosta-2 was resistant in both laboratory tests. Even if the Khosta-2 coronavirus would not yet be dangerous if humans were infected, it could combine with Sars-CoV-2 in a so-called co-infection and become a dangerous recombination. Such a double infection is possible in both humans and animals.
The team writes that a recombination of Khosta-2 and Sars-CoV-2 is a realistic scenario given that transmissions of Sars-CoV-2 from humans back to animals have already been proven. It is therefore only a matter of time before new coronavirus variants appear that can make people sick. The findings of the researchers on Khosta-2 made it clear the need to develop universal vaccines to protect not only against already known variants of Sars-CoV-2, Letko sums up.