FIG 5.
rVSV Delta SP vaccine candidates elicited neutralization antibodies. The neutralization titers (50% inhibition) in immunized mice sera against SpΔCWT-Luc-PVs (A), SpΔCDelta (B.1.617.2)-Luc-PVs (B), SpΔCBeta’-Luc-PVs (D), SpΔCB.1.617-Luc-PVs (E), and SpΔCOmic-Luc-PVs (F) infections. VSV-G-Luc-PVPs (C) were used as the negative control. The mouse serum of each immunization group collected on day 28 was pooled, 2× serially diluted, and incubated with different Luc-PVs (~104 RLU). Then, the mixtures were added in A549ACE2.cell cultures and the infection of PVs was determined by Luciferase assay at approximately 48 to 66 h postinfection. The percentage of infection was calculated compared with no serum control and neutralizing titers were calculated by using sigmoid 4PL interpolation with GraphPad Prism 9.0, as described in the Materials and Methods. Data represent mean ± SD and were obtained from over three independent experiments. Statistical significance was determined using an ordinary one-way ANOVA test and Turkey’s test. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001.