Characterization of local SARS-CoV-2 isolates and pathogenicity in IFNAR−/- mice

Abstract

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recently a global pandemic with unprecedented public health, economic and social impact. The development of effective mitigation strategies, therapeutics and vaccines relies on detailed genomic and biological characterization of the regional viruses. This study was carried out to isolate SARS-CoV-2 viruses circulating in Anatolia, and to investigate virus propagation in frequently-used cells and experimental animals. We obtained two SARS-CoV-2 viruses from nasopharngeal swabs of confirmed cases in Vero E6 cells, visualized the virions using atomic force and scanning electron microscopy and determined size distribution of the particles. Viral cytopathic effects on Vero E6 cells were initially observed at 72 h post-inoculation and reached 90% of the cells on the 5th day. The isolates displayed with similar infectivity titers, time course and infectious progeny yields. Genome sequencing revealed the viruses to be well-conserved, with less than 1% diversity compared to the prototype virus. The analysis of the viral genomes, along with the available 62 complete genomes from Anatolia, showed limited diversity (up to 0.2% on deduced amino acids) and no evidence of recombination. The most prominent sequence variation was observed on the spike protein, resulting in the substitution D614G, with a prevalence of 56.2%. The isolates produced non-fatal infection in the transgenic type I interferon knockout (IFNAR −/- ) mice, with varying neutralizing antibody titers. Hyperemia, regional consolidation and subpleural air accumulation was observed on necropsy, with similar histopathological and immunohistochemistry findings in the lungs, heart, stomach, intestines, liver, spleen and kidneys. Peak viral loads were detected in the lungs, with virus RNA present in the kidneys, jejunum, liver, spleen and heart. In conclusion, we characterized two local isolates, investigated in vitro growth dynamics in Vero E6 cells and identified IFNAR−/− mice as a potential animal model for SARS-CoV-2 experiments.

Induction of alarmin S100A8/A9 mediates activation of aberrant neutrophils in the pathogenesis of COVID-19

“…IFNAR-deficient mice have been suggested as a potential animal model for SARS-CoV-2 experiments (Hanifehnezhad et al, 2020). In this study, we attempted to establish a mouse model of coronavirus-related severe acute respiratory distress syndrome (ARDS) by MHV.…”

A cross-sectional overview of SARS-CoV-2 genome variations in Turkey

“…In the study, the most frequently-detected variations, namely the A23403G, C14408T and GGG28881AAC mutations resulting in amino acid substitutions in the corresponding virus proteins, were reported in previous analyses from Turkey [23][24][25]. However, they seem to be positively-selected in the local virus population pool, as their abundance seem to be elevated.…”

An in vitro study regarding an animal model for the attenuation of SARS-CoV-2: Are cats possible candidates?

“…Research using animal models to investigate the COVID-19 infection has important implications for antiviral and vaccine studies. For instance, transgenic type I interferon knockout mice (IFNAR −/− ) have been suggested as an effective animal model for these studies (Hanifehnezhad et al, 2020). The results obtained in this study showed that cats cannot serve as a suitable animal model for SARS-CoV-2.…”

“…The virus was collected from clari ed cell culture supernatants and aliquoted and frozen at − 80°C until use. The SARS-CoV-2-Ank1 strain used to infect the cells was provided by the Biosafety Level 3 Plus (BSL3+) facility of the Virology Department, Faculty of Veterinary Medicine at Ankara University (Hanifehnezhad et al, 2020).…”