SARS-CoV-2 variants of interest can infect mice: host range extended

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SARS-CoV-2, the virus responsible for COVID-19, is capable of infecting some species, while others are naturally resistant to it. This determines the "host range" of the virus. The SARS-CoV-2 host range includes humans, non-human primates, hamsters, mink and cats. Since the start of the pandemic, mice and rats had proven to be resistant to SARS-CoV-2, because their ACE2 receptor, which allows the virus to enter cells, is very different from the human receptor. Because of its structure, this receptor prevents sufficient contact between the virus and the cell and confers protection on these animals. Scientists from the Institut Pasteur have demonstrated that, unlike the first identified strain, the new SARS-CoV-2 variants of concern (VOCs) are capable of infecting animal models in the laboratory. This research was published as a preprint on the bioRxiv website on March 18, 2021.

In late 2020, variants of SARS-CoV-2 detected in several world regions were labeled as "variants of concern" because they were spreading more rapidly. They are currently being carefully monitored because of their transmissibility and their potential to evade the immune response. These VOCs identified in the United Kingdom (strain B.1.1.7), South Africa (strain B.1.351) and Brazil (strain P.1) have a number of mutations, including changes to the spike protein (the "entry key" that allows SARS-CoV-2 to enter human cells).

"The data obtained show that the VOCs are naturally capable of infecting laboratory mice, unlike the first identified SARS-CoV-2 strain," notes Etienne Simon-Lorière, Head of the Evolutionary Genomics of RNA Viruses Laboratory at the Institut Pasteur and last author of the study. This opens up new possibilities for research into the pathophysiology of SARS-CoV-2 in an animal model by scientists.

"At this stage, it has not yet been determined whether the VOCs can be transmitted from infected mice to mice that have never been infected by SARS-CoV-2, known as naive mice, or to humans, either through close contact or by aerosol transmission. But these results demonstrate that the VOCs extend the host range of SARS-CoV-2 at least to mice (in the laboratory or in the natural environment), and potentially also to other rodents," explains Xavier Montagutelli, Head of the Mouse Genetics Laboratory at the Institut Pasteur.

These findings should stimulate developments in the monitoring of possible animal reservoirs as part of a "one health" strategy that promotes a multidisciplinary, comprehensive approach to health challenges, taking into account the close links between human and animal health.


The B.1.351 and P.1 variants extend SARS-CoV-2 host range to mice, BioRxiv, 18 mars 2021

Xavier Montagutelli1*, Matthieu Prot2, Laurine Levillayer3, Eduard Baquero Salazar4, Grégory Jouvion5-6, Laurine Conquet1, Flora Donati7,8, Mélanie Albert7,8, Fabiana Gambaro2,9, Sylvie Behillil7,8, Vincent Enouf7,8, Dominique Rousset10, Jean Jaubert1, Felix Rey4, Sylvie van der Werf7,8, Etienne Simon-Loriere2*

1 Mouse Genetics Laboratory, Institut Pasteur, Paris, France
2 Evolutionary Genomics of RNA Viruses, Institut Pasteur, Paris, France
3 Functional Genetics of Infectious Diseases, Institut Pasteur, Paris, France
4 Structural Virology, Institut Pasteur, Paris, France
5 Ecole Nationale Vétérinaire, Unité d'Histologie et d'Anatomie Pathologique, Maisons-Alfort,France
6 Université Paris Est Créteil, ENVA, ANSES, Unité DYNAMIC, Créteil, France
7 Molecular Genetics of RNA viruses, CNRS UMR 3569, Université de Paris, Institut Pasteur, Paris, France
8 National Reference Center for Respiratory Viruses, Institut Pasteur, Paris, France
9 Université de Paris, Paris, France
10 Institut Pasteur de la Guyane, Laboratoire de Virologie, Cayenne, French Guiana, France.

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