Lethality of SARS-CoV-2 infection in K18 human angiotensin-converting enzyme 2 transgenic mice

Abstract

Vaccine and antiviral development against SARS-CoV-2 infection or COVID-19 disease would benefit from validated small animal models. Here, we show that transgenic mice expressing human angiotensin-converting enzyme 2 (hACE2) by the human cytokeratin 18 promoter (K18 hACE2) represent a susceptible rodent model. K18 hACE2 transgenic mice succumbed to SARS-CoV-2 infection by day 6, with virus detected in lung airway epithelium and brain. K18 ACE2 transgenic mice produced a modest TH1/2/17 cytokine storm in the lung and spleen that peaked by day 2, and an extended chemokine storm that was detected in both lungs and brain. This chemokine storm was also detected in the brain at day 6. K18 hACE2 transgenic mice are, therefore, highly susceptible to SARS-CoV-2 infection and represent a suitable animal model for the study of viral pathogenesis, and for identification and characterization of vaccines (prophylactic) and antivirals (therapeutics) for SARS-CoV-2 infection and associated severe COVID-19 disease.

Efficacy of GC-376 against SARS-CoV-2 virus infection in the K18 hACE2 transgenic mouse model

“…By 6 dpc, mice in G3 (high virus dose/vehicle, white symbols) showed about 20% weight loss and by 8 dpc there were no survivors because they have either succumbed to the infection or had to be humanely euthanized due to severe clinical signs (lethargy, ruffled fur, labored breathing, and/or ≥25% body weight loss, Fig 2D). These observations are consistent with previous reports 20,21,24,25 . G4 mice (high virus dose/GC-376) showed similar clinical signs but such progression was delayed by about 24 h (~15% weight loss by 6 dpc).…”

Selection, identification, and characterization of SARS-CoV-2 monoclonal antibody resistant mutants

“…An important consideration for selecting an appropriate cell line for the proposed studies is permissibility to SARS-CoV-2 infection. In this study, we used Vero E6 cells, a cell line that has been shown to be permissive to SARS-CoV-2 infection and widely used for the study of SARS-CoV-2 ( Chiem et al, 2020 ; Ye et al, 2020 ; Oladunni et al, 2020 ; Park et al, 2021 ). Other permissive cell types, such as Vero E6 transfected to express transmembrane protease serine 2 (TMPRSS2), a serine protease which activates SARS-CoV-2 infection ( Matsuyama et al, 2020 ); human 293 T ( Crawford et al, 2020 ) or A549 ( Chen et al, 2020 ) cells constitutively expressing the human angiotensin converting enzyme 2 (hACE2), or Calu3 cells ( Felgenhauer et al, 2020 ), could be used instead of Vero E6 cells for the proposed experiments.…”

“…For the experiments in this manuscript we used SARS-CoV-2 isolate USA-WA1/2020 obtained from BEI Resources ( Chiem et al, 2020 ; Ye et al, 2020 ; Oladunni et al, 2020 ; Park et al, 2021 ). We recommend using a multiplicity of infection (MOI) of 0.001 for the first passage in a 12-well plate.…”

Cyclic gallium-68 labeled peptides for specific detection of human angiotensin-converting enzyme 2

“…Humanized ACE2 recombinant mice (B6.Cg-Tg(K18-ACE2)2Prlmn/J, 034860, Jackson Laboratory) were obtained from Jackson Labs, aged 6-10 weeks [38][39][40] .…”

“…All animal procedures were approved by the UCSF Institutional Animal Care and Use Committee, and all studies were performed in accordance with UCSF guidelines regarding animal housing, pain management, and euthanasia. Humanized ACE2 recombinant mice (B6.Cg-Tg(K18-ACE2)2Prlmn/J, 034860, Jackson Laboratory) were obtained from Jackson Labs, aged 6-10 weeks 38–40 . Single time-point imaging: A tail vein catheter was placed in mice under isoflurane anesthesia.…”