Fig. 3: Protective antibodies have multiple neutralization mechanisms.

a Inhibition of fusion in 293T cells cotransfected with plasmids encoding full-length of G and T5F by antibodies. Arrows point to typical syncytia. b The ability of antibodies to block the binding of recombinant receptors to soluble G ectodomains was tested by Luminex assays. The magenta to white gradient grid indicates an IC50 value ranging from 0 to 10 μg ml−1, and gray grids indicate that no blocking activity was detected (see also Supplementary Fig. 5b). The ability of antibodies to block EB2-Fc (c, d) or NiVBD-GHD (e) binding when full-length NiVBD (c)/HeV G (d) or ephrin B2 (e) was anchored on the 293T membrane. The relative binding percentage was calculated as the ratio of positive cells in the presence or absence of antibodies. EB2-Fc (c, d) or NiVBD-GHD (e) was used as a positive control. Data are presented as the mean ± s.d. of three replicates. The ability of antibodies to block the adhesion of rHIV-NiVBD (f) or rHIV-NiVMY (g) virions (mean ± s.d. of triplicate measurements). In Dunnett’s multiple comparisons test, the mean difference (MD), 95% Confidence interval (CI), and P value were [94.87, 78.35–111.4, P < 0.0001] (f) and [86.47, 69.35–103.6, P < 0.0001] (g) for 1E5, [19.6, 3.08–36.12, P = 0.023] (f) and [−18.5, −35.62 to −1.38, P = 0.036] (g) for 1F9, and [8.5, −8.02 to 25.02, P = 0.371] (f) and [10.9, −6.22 to 28.02, P = 0.232] (g) for 1B6, respectively. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, ns, not significant. The EBOV-specific antibody 2G1 was used as an isotype control (c–g). h, i Hamster protection studies. Kaplan–Meier survival curve (left) and weight change (right, data are presented as mean ± s.d.) of hamsters treated with 450 μg (h) or 1 mg (i) of antibody (n = 6). The P value and the asterisk indicate statistical significance determined by a Mantel-Cox log-rank test. The color of the survival curve for each antibody matches that of the weight change curve on the right of the chart. Source data are provided as a Source Data file.