SARS-CoV-2 Neutralization Test
Neutralizing antibodies were evaluated by titration of sera against
SARS-CoV-2 pseudotyped Vesicular Stomatitis Virus (VSV). The test is
based on VSV-ΔG*FLuc pseudotyped with SARS-CoV-2-Spike-ΔER which
correlates with SARS-CoV-2 neutralization as described
previously.13,14 Pseudoviral titers were determined by
limited dilution and fluorescence microscopy. For all samples, a fixed
inoculum of 25,000 ffu was neutralized for 1 h and luciferase activity
was determined 20 h post infection of
HEK293T-ACE2+-cells. IC50 values were fitted using the
algorithm: ‘log (inhibitor) vs. normalized response’ and further
analyzed in GraphPad Prism 8 software (GraphPad Software, San Diego,
USA).