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

Authors: Kapczynski, Darrell; Sweeney, Ryan; Spackman, Erica; Pantin Jackwood, Mary; Suarez, David

Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/26/2022
Publication Date: 2/12/2022
Citation: Kapczynski, D.R., Sweeney, R.P., Spackman, E., Pantin Jackwood, M.J., Suarez, D.L. 2022. 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. Virology. 569:1-12. https://doi.org/10.1016/j.virol.2022.01.014.
DOI: https://doi.org/10.1016/j.virol.2022.01.014

Interpretive Summary: The current pandemic is caused by a coronavirus known as SARS-CoV-2. The virus infects humans and other animal species. These animals have the potential to transmit virus to humans. We developed a model of SARS-CoV-2 infection in a cell line that mimics infection in humans and animals. Using this model we demonstrate susceptibility and resistance to SARS-CoV-2 in different animal species. Results from our model positively correlates with published studies were animals were directly infected.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 variants.

Technical 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.