Mouse-adapted SARS-CoV-2 protects animals from lethal SARS-CoV challenge
Fig 3
CMA3p20 strain maintains human replication capacity and antigenicity.
(a and b) Primary human airway cultures were infected with SARS-CoV-2 WT (black square) or CMA3p20 (blue circles) at an MOI of 0.01 and evaluated for (a) viral titer and (b) viral RNA (n = 3). (c) Sera collected from female BALB/c mice 28 days postinfection with 106 PFU of SARS-CoV-2 CMA3p20 were evaluated for capacity to neutralize WT SARS-CoV-2 (WA1), B.1.1.7, and B.1.351 via PRNT50 assay (n = 12). Log10 value of dilution used to plot points on the x-axis. (d) PRNT50 values from COVID-19 patient sera plotted against WT virus (y-axis) versus CMA3p20 virus (x-axis). (e and f) Ten-week-old female BALB/c mice were treated intraperitoneally with 100 ul of human COVID-19 sera (n = 10) or control (PBS, n = 10) 1 day prior to infection. Mice were subsequently challenged with 105 PFU of SARS-CoV-2 CMA3p20 and evaluated for (e) weight loss and (f) viral titer in the lung (n = 5). Data presented as mean values +/− SD in (a–c) and +/− SEM in (e). P values based on a 2-tailed Student t test. Raw data are available in S3 Data. COVID-19, Coronavirus Disease 2019; MOI, multiplicity of infection; PFU, plaque-forming unit; PRNT, plaque reduction neuralization titer; SARS-CoV-2, Severe Acute Respiratory Syndrome Coronavirus 2; WT, wild-type.