Elsevier

Virology

Volume 569, April 2022, Pages 1-12
Virology

Development of an in vitro model for animal species susceptibility to SARS-CoV-2 replication based on expression of ACE2 and TMPRSS2 in avian cells

https://doi.org/10.1016/j.virol.2022.01.014Get rights and content
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Highlights

  • Identification of animals susceptible to SARS-CoV-2 will provide data on zoonotic reservoirs and transmission potential.

  • This work provides a model system to test the ability of the virus to replicate in a non-permissive avian cell line.

  • Results from the in vitro model positively correlate with animal infection studies enhancing the predicative capability.

  • Here we demonstrate that both ACE2 and TMPRSS2 proteins are required for successful virus replication in DF1 cells.

  • This work creates a means to test animal species for susceptibility to infection that may be reservoirs for transmission.

Abstract

The SARS-CoV-2 (SARS-CoV-2) virus has caused a worldwide pandemic because of the virus's ability to transmit efficiently human-to-human. A key determinant of infection is the attachment of the viral spike protein to the host receptor angiotensin-converting enzyme 2 (ACE2). Because of the presumed zoonotic origin of SARS-CoV-2, there is no practical way to assess the susceptibility of every species to SARS-CoV-2 by direct challenge studies. In an effort to have a better predictive model of animal host susceptibility to SARS-CoV-2, we expressed the ACE2 and/or transmembrane serine protease 2 (TMPRSS2) genes from humans and other animal species in the avian fibroblast cell line, DF1, that is not permissive to infection. We demonstrated that expression of both human ACE2 and TMPRSS2 genes is necessary to support SARS-CoV-2 infection and replication in DF1 and a non-permissive sub-lineage of MDCK cells. Titers of SARS-CoV-2 in these cell lines were comparable to those observed in control Vero cells. To further test the model, we developed seven additional transgenic cell lines expressing the ACE2 and TMPRSS2 derived from Felis catus (cat), Equus caballus (horse), Sus domesticus (pig), Capra hircus (goat), Mesocricetus auratus (Golden hamster), Myotis lucifugus (Little Brown bat) and Hipposideros armiger (Great Roundleaf bat) in DF1 cells. Results demonstrate permissive replication of SARS-CoV-2 in cat, Golden hamster, and goat species, but not pig or horse, which correlated with the results of reported challenge studies. Cells expressing genes from either bat species tested demonstrated temporal replication of SARS-CoV-2 that peaked early and was not sustained. The development of this cell culture model allows for more efficient testing of the potential susceptibility of many different animal species for SARS-CoV-2 and emerging variant viruses.

Keywords

SARS-CoV-2
ACE2
TMPRSS2
Animal
Replication
Model

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