Fig 2. COVID-19+ convalescent and acute illness sera inhibit cell fusion in the transient system.

Four-fold serially-diluted serum samples were pre-incubated with spike-expressing producer cells for 1 hour, then hACE2-expressing target cells were added, as per S3 Fig. RLU was measured the next day (A-L), and IC₅₀ values calculated for each (M). Similarly, IC₅₀ values were calculated for pseudotyping, performed as in Fig 1 (N). Correlation between IC₅₀ values for the transient cell fusion and S-pseudotyping (O).