On August 4, the Chinese Academy of Agricultural Sciences (CAAS) studied the establishment of a novel CoronavirusSARS-COV-2 infection model that can be stable and effective replication in both upper and lower respiratory tracts in mice. It is found that mice are naturally not susceptible to SARS-COV-2, and the development of a mouse infection model that is susceptible to SARS-COV-2 has irreplaceable value, providing an important means for in-depth exploration of the mechanism of SARS-COV-2 infection and immunity.

Using sarS-COV-2 virus strains isolated from clinical samples, the team members infected BALB/ C mice at 4-6 weeks of age through the nasal passage, and rapidly passed through 14 generations. A mouse strain of SARS-CoV-2 was obtained. High levels of virus replication were detected in the turbinates and lungs on the 3rd and 5th days after infection, and typical pneumonia lesions were caused in elderly BALB/ C mice during August and September.By comparing the HRB26 and HRB26M genomes, it was found that mouse adaptation resulted in three amino acid site mutations and one deletion, namely, nSP8 protein A81T, S protein Q498H and N969S, and the deletion of 675-679 near the cleavage site of S protein. Using adaptive HRB26M the mathematical models of mice infected with strains, evaluated the dosage rhett west wei different inhibiting SARS - CoV - 2 effect in vivo, confirmed that the muscle injection and intranasal administration can completely prevent the replication of virus in the middle turbinate and lung, hint clinically used when rhett wei treatment of patients with a new crown to the west, should consider the combination of muscle injection and intranasal drug delivery way.

This BALB/ C inbred mouse is the experimental animal with the clearest background, most extensive application and most in-depth study. The establishment of its infection model opens up huge research resources for the large-scale selection and evaluation of coVID-19 candidate vaccines and antiviral drugs.C57BL/6J mouse is the most commonly used gene knockout mouse strain. The establishment of its infection model provides an important means for further exploring the infection and immune mechanism of novel Coronavirus.

Time：2020.08.11

Source：http://www.caas.cn/xwzx/tpxw/306924.html