Fig. 4From: Neutralization assay with SARS-CoV-1 and SARS-CoV-2 spike pseudotyped murine leukemia virionsNeutralizing activity of COVID-19 patient serum against SARS-CoV-1 pseudovirions. a Serum from COVID-19 patients were pre-incubated with SARS-CoV-1 spike pseudotyped MLV at 37 °C for 1 h. Serum and virus mixture were then incubated with HEK293T-ACE2 cells. b NT50 and NT80 were calculated as above. Samples #1, 2 and 3 were tested previously (Fig. 2)Back to article page