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Structural and molecular basis for Ebola virus neutralization by protective human antibodies

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Science  18 Mar 2016:
Vol. 351, Issue 6279, pp. 1343-1346
DOI: 10.1126/science.aad6117
  • Fig. 1 Binding requirements and structure of antibodies in complex with GP.

    (A) Schematic representation of GP monomer, colored by domain. GP1 core region (33 to 190) is colored blue, GP1 glycan cap is colored yellow (201 to 308), and the mucin-like domain is uncolored (309 to 501). The GP2 IFL is colored red, and the remainder of GP2 is colored orange. Glycans are shown as branched lines, and proteolytic cleavage sites are labeled with arrows. Disulfide bonds within and between GP1 and GP2 are omitted for clarity. (B) IP of soluble GP ectodomain containing or lacking the mucin-like domain (GPΔMuc) by mAb100, mAb114, or isotype control. Binding and input were analyzed using immunoblotting for GP1. *GP1 degradation product present only in mucin-containing GP. n = 3 replicates; representative image shown. (C) Crystal structure of GPΔMuc in complex with Fab100 and Fab114. Fab100 is shown in purple (heavy chain) and white (light chain). Fab114 is shown in pink (heavy chain) and white (light chain). Molecular surfaces of two GPΔMuc protomers are colored in green and beige, whereas the third is shown as a ribbon representation and colored according to the schematic in (A).

  • Fig. 2 Cryo-EM of GPΔMuc-Fab100-Fab114 complex.

    Cryo-EM was performed on the ternary complex of GPΔMuc with Fab100 and Fab114 at (A) pH 7.4 and (B) pH 5.0. Shown are the superimpositions of the crystal structure (ribbon) into the cryo-EM density maps at their respective pH.

  • Fig. 3 mAb100 inhibits cathepsin cleavage of GP.

    (A) Fab100 binding occludes access to the β13-β14 loop of GP1. Protomers and Fab100 heavy and light chains are colored and oriented as in Fig. 1C. The variable domain of one Fab100 is shown in a ribbon representation, and all other Fabs are removed for clarity. Inset shows a zoomed view of the Fab100-GP interface with the difference map generated by masking out the cryo-EM densities of the fitted crystal structures shown as a gray transparent surface. The β13-β14 loop is shown as a dashed yellow line connecting the GP1 core (blue) and the glycan cap (yellow). (B) GPΔMuc was incubated with the indicated antibodies followed by cleavage at pH 5.5 by Cat L at 37°C. Samples were removed at 5-min intervals and analyzed by immunoblot for GP1. n = 3 replicates; representative image shown. (C) Binding kinetics, as determined by biolayer interferometry, of GPΔMuc or GPTHL (THL) with Fab100 or KZ52 at the indicated pH. KDs are plotted on a negative log scale. n = 2 replicates; representative experiment shown.

  • Fig. 4 mAb114 blocks binding of NPC1 to the GP1 core.

    (A) Fab114 binds to regions in the glycan cap and core of GP1. Protomers are colored as in Fig. 1C and viewed with a 100° rotation about the trimeric axis with respect to the orientation in Fig. 1C. The variable domain of a single Fab114 is shown in ribbons, and all other Fabs have been removed for clarity. GP residues predicted to make contact with Fab114 are shown as transparent surfaces. (B) Immunoprecipitation of GPΔMuc and GPTHL by the indicated antibodies. Samples were analyzed by immunoblot for GP1. n = 3 replicates; representative image shown. (C) Class averages of single particles from negative-stain electron micrographs of Fab114 in complex with GPΔMuc and GPTHL. (D) Binding kinetics, as determined by biolayer interferometry, of GPΔMuc or GPTHL with Fab114, 13C6, or NPC1-dC at the indicated pH. KDs are plotted on a negative log scale. *No binding. n = 2 replicates; representative experiment shown. (E) Inhibition of NPC1-dC binding to GPTHL by competitor proteins (NPC1-dC) or antibodies (mAb100, mAb114, 13C6, KZ52, or isotype control) was determined by biolayer interferometry. Dashed line represents 60% inhibition of binding. n = 3 replicates; representative experiment shown.

Supplementary Materials

  • Structural and molecular basis for Ebola virus neutralization by protective human antibodies

    John Misasi, Morgan S. A. Gilman, Masaru Kanekiyo, Miao Gui, Alberto Cagigi, Sabue Mulangu, Davide Corti, Julie E. Ledgerwood, Antonio Lanzavecchia, James Cunningham, Jean Jacques Muyembe-Tamfun, Ulrich Baxa, Barney S. Graham, Ye Xiang, Nancy J. Sullivan, Jason S. McLellan

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods
    • Figs. S1 to S7
    • Table S1
    • References

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