Figure 2. Infectivity and neutralization of spike pseudoparticles.
(A) Schematics of the spike mutants generated to study the effect of ICS-05/03–specific mutations. Amino acid positions are represented with respect to the Wuhan HU-1 sequence (NC_045512). (B) Infectivity profiles of the indicated spike mutant–pseudotyped lentiviruses. The infectivity was normalized to the D614G-pseudotyped lentiviral particles. The data represent the mean of three replicates, and the significance was measured by the one-way ANOVA multiple comparison test to analyze the difference between the groups, n = 3. *P < 0·05, **P < 0·01, ***P < 0·001, ns, nonsignificant. (C) Western blots showing the relative expression of the indicated spike proteins bearing mutations from the producer cell lysates and the viral lysates. β-actin and p24 served as loading controls for cell lysates and viral lysates, respectively. (D) The susceptibility of each spike mutant PV to neutralization by antibodies in the plasma obtained from vaccinated, test-negative individuals is plotted. Each data point represents mean NT50 values (50% neutralization titre) obtained against the indicated virus. The NT50 values were determined in triplicate, and geometrical means were calculated. The dotted red line represents the median response of each spike PV. The fold difference in response to the neutralizing plasma was measured compared to the reference D614G mutant spike PV (n = 6). The statistical significance was calculated by the Wilcoxon signed-rank test, two-tailed, nonparametric.
Source data are available for this figure.
