Structural basis of broad protection against influenza virus by human antibodies targeting the neuraminidase active site via a recurring motif in CDR H3.
Jo, G., Yamayoshi, S., Ma, K.M., Swanson, O., Torres, J.L., Ferguson, J.A., Fernandez-Quintero, M.L., Huang, J., Copps, J., Rodriguez, A.J., Steichen, J.M., Kawaoka, Y., Han, J., Ward, A.B.(2025) Nat Commun 16: 7067-7067
- PubMed: 40750588 
- DOI: https://doi.org/10.1038/s41467-025-62174-2
- Primary Citation of Related Structures:  
9CYE, 9CYF, 9CYG, 9CYH, 9CYI, 9CYJ, 9O4N, 9O4O, 9O4P, 9O4Q - PubMed Abstract: 
Influenza viruses evolve rapidly, driving seasonal epidemics and posing global pandemic threats. While neuraminidase (NA) has emerged as a vaccine target, shared molecular features of NA antibody responses are still not well understood. Here, we describe cryo-electron microscopy structures of the broadly protective human antibody DA03E17, which was previously identified from an H1N1-infected donor, in complex with NA from A/H1N1, A/H3N2, and B/Victoria-lineage viruses. DA03E17 targets the highly conserved NA active site using its long CDR H3, which features a DR (Asp-Arg) motif that engages catalytic residues and mimics sialic acid interactions. We further demonstrate that this motif is conserved among several NA active site-targeting antibodies, indicating a common receptor mimicry strategy. We also identified BCR sequences containing this DR motif across all donors in a healthy human repertoire database, suggesting that such precursors may be relatively common and have vaccine targeting potential. Our findings reveal shared molecular features in NA active site-targeting antibodies that can be harnessed to design broad, immune-focused influenza vaccines.
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA.
Organizational Affiliation: