Abstract
The inherent instability of poliovirus capsids presents a formidable challenge for developing next-generation vaccines suitable for a post-eradication world. Here, we address this by engineering a thermally stabilized virus-like particle (sVLP) derived from the poliovirus serotype 1 (PV1) Mahoney-SC7 mutant and elucidating its atomic-level structure. Produced at remarkably high yields in Pichia pastoris yeast, our engineered sVLP maintains a native, D-antigenic conformation and elicits a potent neutralizing antibody response in mice, in sharp contrast to unstable wild-type VLP (wtVLP) which adopts an expanded, non-immunogenic form. Our 2.43 Å resolution cryo-EM structure reveals precisely how seven stabilizing mutations cooperatively enhance inter-protomer contacts and rigidify surface loops to lock the particle in its immunogenic state. We further define a critical D-antigenic epitope by determining the 2.60 Å structure of the sVLP in complex with a novel D-antigen-specific, neutralizing monoclonal antibody, 3G10, elucidating the structural mechanisms of D-antigen recognition and virus neutralization by 3G10. These findings provide a definitive structural blueprint for engineering stable, immunogenic vaccines for PVs and other enteroviruses and also deliver a vital reagent for ensuring vaccine quality control.
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Data availability
Cryo-EM maps have been deposited in the Electron Microscopy Data Bank (http://www.emdataresource.org) with the accession numbers of EMD-65817 for wtVLP, EMD-65818 for sVLP, and EMD-65819 for sVLP-3G10. The associated models have been deposited to the Protein Data Bank (https://www.rcsb.org/) with accession codes 9WAG, 9WAH, and 9WAI.
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Acknowledgements
We are grateful to the staff of the NCPSS Electron Microscopy Facility, Database and Computing Facility, and Protein Expression and Purification Facility for instrument support and technical assistance. This work was supported by grants from the National Natural Science Foundation of China (32370991 to Z.H.), National Key R&D Program of China (2024YFA1803102 to Y.C.), the Shanghai Municipal Science and Technology Major Project (ZD2021CY001 to Z.H.), the Strategic Priority Research Program of CAS (XDB0570000 to Y.C.), the NSFC (32130056, 32570924 to Y.C.), and the Shanghai Pilot Program for Basic Research from CAS (JCYJ-SHFY-2022-008 to Y.C.). Q.H. was supported by the China National Postdoctoral Program for Innovative Talents (BX20250141).
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Z.H., Y.C., X.W., and Q.L. designed the experiments. T.C., W.H., S.W., C.Y.L. (Chaoyang Lian), Y.Z., L.R., T.W., and C.S. performed the biochemical and animal experiments. Q.H. collected the cryo-EM data and performed cryo-EM reconstructions and model building. C.L. is involved in the initial cryo-EM sample screen. Q.H., T.C., and W.H. analyzed the data. Z.H., Y.C., X.W., Q.L., Q.H., and T.C. wrote the manuscript.
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W.H., C.L., L.R., Q.L., and X.W. are current employees of Huasong (Shanghai) Biomedical Technology Co., LTD. Q.L., X.W., L.R., T.C., and W.H. are inventors of a patent (CN 202410797193.1) on the 5C6 mAb owned by Huasong (Shanghai) Biomedical Technology Co., LTD. Q.L., X.W., L.R., C.Y.L., Z.H., and T.C. are listed as inventors in a pending patent application (CN 202511196350.4) on the 3G10 mAb filed by Huasong (Shanghai) Biomedical Technology Co., LTD. The other authors declare that they have no competing interests.
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Hong, Q., Chen, T., Han, W. et al. Structural insight into the assembly and D antigenicity of polio type 1 stabilized virus-like particles. npj Vaccines (2026). https://doi.org/10.1038/s41541-026-01404-0
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DOI: https://doi.org/10.1038/s41541-026-01404-0
