A protective and heterosubtypic antibody lineage targeting the influenza A virus neuraminidase active site
Ty A. Sornberger, Rachael M. Wolters, Iuliia M. Gilchuk, Luke Myers, Elad Binshtein, Ryan Irving, Elaine C. Chen, Pavlo Gilchuk, Rachel S. Nargi, Rachel E. Sutton, Bethany N. Howard, Laura S. Handal, Andrew Trivette, Katherine E. Webb, Chandrahaas Kona, Eduardo Villalobos, Lauren E. Williamson, James E. Crowe Jr., Seth J. Zost
Ty A. Sornberger, Rachael M. Wolters, Iuliia M. Gilchuk, Luke Myers, Elad Binshtein, Ryan Irving, Elaine C. Chen, Pavlo Gilchuk, Rachel S. Nargi, Rachel E. Sutton, Bethany N. Howard, Laura S. Handal, Andrew Trivette, Katherine E. Webb, Chandrahaas Kona, Eduardo Villalobos, Lauren E. Williamson, James E. Crowe Jr., Seth J. Zost
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Research Article Immunology Infectious disease

A protective and heterosubtypic antibody lineage targeting the influenza A virus neuraminidase active site

Abstract

Influenza type A viruses (IAVs) remain an extraordinary burden to global public health and regularly circulate through human populations. This investigation describes the isolation of human mAbs from an individual with a substantial history of influenza exposure via vaccination and natural infection. From these mAbs, a clonally expanded B cell lineage was identified that recognizes the IAV neuraminidase (NA) glycoprotein and binds near the NA active site of H3N2 viruses to inhibit sialidase activity. Further characterization found that some somatically mutated members of this lineage exhibited cross-reactive binding to recombinant N1 and N9 antigens, suggesting that heterosubtypic reactivity was acquired through somatic mutation. Two candidate mAbs from this family — FluA-168 and FluA-173 — potently inhibited IAV replication in vitro and protected against lethality in vivo. The results of this study contribute to our understanding of cross-reactivity between IAV subtypes in response to diverse exposure patterns and identified 2 mAbs as potential therapeutic candidates for IAV infection.

Authors

Ty A. Sornberger, Rachael M. Wolters, Iuliia M. Gilchuk, Luke Myers, Elad Binshtein, Ryan Irving, Elaine C. Chen, Pavlo Gilchuk, Rachel S. Nargi, Rachel E. Sutton, Bethany N. Howard, Laura S. Handal, Andrew Trivette, Katherine E. Webb, Chandrahaas Kona, Eduardo Villalobos, Lauren E. Williamson, James E. Crowe Jr., Seth J. Zost

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Figure 3

mAbs interact with conserved residues of the NA active site.

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mAbs interact with conserved residues of the NA active site. (A–D) Zanam...
(A–D) Zanamivir-competition ELISA showing binding reactivity of FluA-168 and FluA-173, positive control mAbs r1G01 and rFNI9, and isotype-negative control mAb r2D22 to rN2 and rN9 antigens in the presence of zanamivir. Data points and error bars indicate mean ± SD. All mAbs were assessed in triplicate across 2 biological replicates. (E) Negative stain electron microscopy (NS-EM) micrograph with 2D class averages shown. Original magnification ×50,000 with a pixel size of 2.18 Å per pixel. Top and side views of the NS-EM reconstruction of representative mAb FluA-170 Fab molecules in complex with one rN2 (gray; A/Singapore/1/1957) are shown. The Fv region of positive control mAbs 1G01 (purple; PDB ID: 6Q23) and FNI9 (orange; PDB ID: 8G30) is also shown in complex with the rN2 antigen. (F) Network of polar interactions between Y103, F104, R106, and D107 in the HCDR3 of FNI9 (orange) to R118, D151, R152, and R371 of N2 (gray) based on PDB: 8G30. (G) Network of polar interactions between Y106, T107, R108, and G109 in the HCDR3 of 1G01 (purple) to R118, D151, R152, and R371 of N1 (gray) based on PDB: 6Q23. (H) Network of polar interactions between zanamivir (ZAN; cyan) and R118, D151, R152, and R371 of N9 (gray) based on PDB: 4MWX. (I) Network of polar interactions between sialic acid (SA; pink) and R118, D151, R152, and R371 of N2 (gray) based on PDB: 4GZQ. Dashed lines indicate interactions within 3.5 Å.