The study reveals how some chiropterans avoid the SARS-CoV-2 infection despite having the receptors (ACE2) of the viral spike protein. Credit: University of Barcelona
Key Points:
- Bats are known reservoir hosts of coronaviruses and immune to infection by SARS-CoV-2.
- Their immune systems are able to continuously fight the virus without triggering an inflammatory response, which other mammals are unable to do.
- Scientists discovered that SARS-CoV2 did not bind to an enzyme in the primary cell of bats.
Clues from the primary cells of bats have allowed a team of scientists to better understand why the animals are resistant to infection by SARS-CoV-2. The team, led by researchers from the Institute Pasteur in Paris, focused on five species of bats that had been previously understudied. They published their findings in the Journal of Virology.
Scientists have long known that bats are reservoir hosts for SARS-CoV2, meaning they can carry the virus without being infected by it. The immune system of bats is in a perpetual state of pre-alert. During that state, brigades of inflammatory cells are dispatched to fight bacteria in the bodies of most mammals. The immune systems of bats, however, are able to exist in that state without triggering an inflammatory response.
Researchers found one potential explanation in how the primary cells of bats replicate SARS-CoV2. They noticed that none of the cells were infected during the process. This was true even in bat cells containing angiotensin-converting enzyme 2 (ACE2), an enzyme many coronaviruses exploit for entry into the cells of other mammals. The researchers, therefore, theorized that either the virus does not enter bat cells, or if it does, it is unable to infect them.
“The cells did not allow the infection in the species Rhinolophus ferrumequinum, a chiropteran from the same genus as the Asian bat in which the BANAL-52 virus was found, a potential ancestor of SARS-CoV-2,” said Jorddi Serra-Cobo, study author and researcher at the University of Barcelona. “Specifically, the genetic sequences of the BANAL-52 virus is 96.8% similar to that of SARS-CoV-2.”
Bats and viruses have a long history of coevolution, and coronaviruses are just one example of that relationship. Next, the research team aims to further investigate this association since bats are reservoir hosts for many other pathogens that are transmissible to humans.