journal article·2026-02Open access

IgG‐Bridging–Seeded Synergistic Aggregation of SARS‐CoV‐2 Spikes Underlies Potent Neutralization by a Low‐Affinity Antibody

Niannian Lv, Peng Chen, Xiaobin Dai, Hu Xu, Ziheng Li, Zelin Shan, Jinqian Li, Fenglin Guo, Yuanfang Chen, Jiayi Li, Yiqian Huang, Guizhi Dong, Yifan Jiang, Liang Chen, Xuanyu Nan, Hanjun Zhao, Kang Zhang, Shilong Fan, Yuanchen Dong, Dongsheng Liu, Xinquan Wang, Deli Huang, Xiaojing Pan, Chunying Chen, Zhihua Liu, Li‐Tang Yan, Qi Zhang, Linqi Zhang, Yuliang Zhao, Yuhe Renee Yang

Advanced Science· Volume 13· Issue 11

Abstract

Abstract Mechanistic studies of viral neutralization typically prioritize high‐affinity antibodies, relegating low‐affinity binders to the sidelines. P5‑1C8, a Class 1 SARS‐CoV‐2 antibody that exemplifies this underexplored “low‑affinity yet high‑potency” phenotype is reported, retaining strong neutralization of Omicron JN.1 despite markedly weakened trimer binding (K D = 225 nM; IC 50 = 0.06 nM). Structural and biophysical analyses reveal that P5‐1C8 engages WT and BA.1 spikes through canonical intra‐spike bivalency, but with JN.1 it induces aggregation. Using virion‐like nanoparticles displaying multiple spikes, it is shown that IgG remains bound with no detectable dissociation and triggers pronounced aggregation. Coarse‐grained molecular dynamics delineate the stepwise pathway in which weak IgG‐spike contacts seed aggregation via transient inter‐spike bridging. Together, these findings establish the first mechanistic framework demonstrating how weak‐binding antibodies can nonetheless achieve potent neutralization through higher‐order aggregation, thereby expanding the conceptual landscape of antibody function and opening new directions for antibody evaluation and design.
Source: crossref · Quality: baseline

Research context

OpenAlex topics: SARS-CoV-2 and COVID-19 Research · Monoclonal and Polyclonal Antibodies Research · Advanced Biosensing Techniques and Applications

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

Affiliations

National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100021 China

Laboratory of Nanosystem and Hierarchical Fabrication National Center for Nanoscience and Technology Beijing 100190 China

Research Unit of Nanoscience and Technology Chinese Academy of Medical Sciences Beijing 100730 China

Comprehensive AIDS Research Center Pandemic Research Alliance Unit Center for Infection Biology School of Basic Medical Sciences Tsinghua University Beijing 100084 China

State Key Laboratory of Chemical Engineering and Low‐carbon Technology Department of Chemical Engineering and Low‐carbon Technology Tsinghua University Beijing 100084 China

CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety National Center for Nanoscience and Technology Chinese Academy of Sciences Beijing 100190 China

College of Ecology Lanzhou University Lanzhou 730000 China

University of Chinese Academy of Sciences Beijing 100049 China

The Salk Institute of Biological Sciences La Jolla CA 92037 USA

The Ministry of Education Key Laboratory of Protein Science Beijing Frontier Research Center for Biological Structure School of Life Sciences Tsinghua University Beijing 100084 China

CAS Key Laboratory of Colloid Interface and Chemical Thermodynamics Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China

MOE Engineering Research Center of Advanced Rare Earth Materials Department of Chemistry Tsinghua University Beijing 100084 China

Shanghai Institute of Infectious Disease and Biosecurity Shanghai Medical College Fudan University Shanghai 200032 China

Centre for Virology Vaccinology and Therapeutics Department of Microbiology Li Ka Shing Faculty of Medicine The University of Hong Kong Hong Kong SAR 999077 China

The technology center for protein science Tsinghua University Beijing 100084 China

Department of Applied Biology and Chemical Technology The Hong Kong Polytechnic University Hong Hum Kowloon 999077 Hong Kong

PolyU Shenzhen Research Institute Shenzhen 518057 China

Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology Life Sciences Institute Zhejiang University Hangzhou 310058 China

Institute of Bio‐Architecture and Bio‐Interactions Shenzhen Medical Academy of Research and Translation Shenzhen Guangdong 518107 China

CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety and CAS Center for Excellence in Nanoscience Beijing 100190 China

Department of Gastrointestinal Oncology Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education) Beijing 100142 China

Institute of Biopharmaceutical and Health Engineering Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen 518055 China

Institute of Biomedical Health Technology and Engineering Shenzhen Bay Laboratory Shenzhen 518132 China

Funding

National Key Research and Development Program of China · Natural Science Foundation of Beijing Municipality · National Natural Science Foundation of China

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