Bats are the natural reservoir for many viruses. The monitoring and study of these by scientists allows us to better understand them and anticipate a potential zoonotic event. In 2020, two viruses of the subgenus Sarbecovius, SARS-CoV-2 itself, were isolated from horseshoe bats in Russia, near the Sochi National Park. Khosta-1 et Khosta-2 appartiennent au clade 3 qui regroup uniquement des animal viruses, since SARS-CoV 1 et 2 are included in clade 1. Il no aucune human infection caused by las Khosta viruses connue à ce day. Sabercoviruses use the ACE-2 protein to infect cells, so this ability was tested for Khosta-1 and Khosta-2 in a study recently published in Plos Pathogens.
Khosta-2, a threat to humans?
To find out if Khosta-1 and 2 use the ACE-2 receptor, the scientists worked only with the viral fragment that interacts with said receptor, the RBD, grafted onto pseudoviruses. in vitroKhosta-1 fails to infect cells in culture that express the human ACE-2 receptor, on the other hand, Khosta-2 does and in the same proportions as RaTG13, a clade 1 bat virus similar to SARS-CoV-2. Additional experiments indicate that Khosta-2 protein S may also interact with ACE-2.
The scientists then tested the ability antibodies present in the serum of people vaccinated against Covid-19 to neutralize a Khosta-2 protein S-carrying pseudovirus. The results show that Khosta-2 protein S is resistant to sera from vaccinees. This is not surprising, as the S proteins of Khosta-2 and SARSCoV-2 are only 60% identical; this is not enough for anti-SARS-CoV-2 antibodies to recognize Khosta-2 and generate protection against it. In view of the data available today, there is no need to worry about a new event…
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