Figure 1.
Structure of the m102.3/HeV-G complex, and comparison to the ephrin-B2/HeV-G structure.
A. Left: Overall Structure of the m102.3/HeV-G complex viewed from the side. CDR-H3 (magenta) of m102.3 inserts into the central cavity of HeV-G (green). Disulfide bonds are shown as yellow sticks. The five glycosylation sites of HeV-G are shown as grey spheres. Right: A close up view of the HeVG/m102.3 complex interface. Residues involved in the interaction are shown as stick figures and labeled. The solvent accessible surface of HeV-G central cavity region, viewed from top, is presented on the bottom. CDR-H3 residues (magenta) and R30 (cyan, on the light chain of Fab) and their contacting residues on HeV-G (green) are shown and labeled. B. Overall structure of the ephrin-B2 (orange)/HeV-G (blue) complex. HeV-G in the complex is in the same orientation as in panel A.
Figure 2.
Comparison of the binding interfaces in the HeV-G/m102.3 and the HeV-G/ephrin-B2 complexes.
A: The solvent accessible surface of the HeV-G molecule in the HeV-G/m102.3 complex viewed from the top. HeV-G is colored in green, except for the m102.3-contacting region that is colored in red (for the 1∶1 complex interface) and in blue (for the region contacted by another copy of the light chain in the hetero-tetrameric 2∶2 complex interface). B: The solvent accessible surface view of the HeV-G molecule in the HeV-G/ephrin-B2 complex viewed from the top. HeV-G is colored in grey, except for the ephrin-B2 contacting region, which is colored in red. C: The tip of the m102.3 CDR-H3 region (in magenta) bound in the HeV-G surface cavity (in green). D: The tip of the ephrin-B2 G-H loop (in yellow) bound in the HeV-G surface cavity (in grey).
Figure 3.
Comparison of the m102.3-binding regions of HeV-G and NiV-G.
The HeV-G (green) and NiV-G (purple) structures are superimposed and viewed from top. The m102.3 contacting residues of HeV-G and the corresponding residues of NiV-G are shown and labeled. Most residues are conserved between HeV-G and NiV-G except for three: T/S241, T/V507 and Y/F458.
Figure 4.
Neutralization efficacy of wild-type and neutralization-escape mutants by m102.4 mAb, m102.4 Fab and m102.3 Fab.
Wild-type (WT) Nipah (NiV) and Hendra (HeV) viruses and their respective m102.4 neutralization escape mutants NiV-V507I and HeV-D582N were used to evaluate the neutralization efficacy of m102.4 mAb, m102.4 Fab and m102.3 Fab. Starting concentration of m102.4 was 100 µg/mL. The mAb and Fab concentrations at which 50% of the virus was neutralized are plotted. Error bars represent standard deviations. * t-test; p<0.001 compared to WT.
Figure 5.
In vitro growth characteristics of wild type NiV and HeV and m102.4 neutralization escape mutants NiV-V507I and HeV-D582N.
Cultures of (A) Vero E6, (B) HeLa-USU cells expressing human ephrin-B2 (HeLa-ephrin-B2) or (C) human ephrin-B3 (HeLa-eprhin-B3) were infected in triplicate with wild type and m102.4 neutralization escape mutants at a multiplicity of infection of 1 as described in Materials and Methods. Virus titers at different time points were determined by TCID50 using Vero E6 cells. Solid black line, NiV; solid grey line, NiV-V507I; dotted black line, HeV; dotted grey line, HeV-D582N. Error bars represent standard deviations.