A High-Throughput Broad Neutralizing Antibody Assay for Detecting SARS-CoV-2 Variant Immunity in Population.

Publication date: Sep 12, 2025

Detecting neutralizing antibodies (NAbs) to SARS-CoV-2 variants that are evolved is crucial to know the escape of host immunity to the newly arising variants. To address this need, we developed a high-throughput broad neutralizing antibody (bNAb) assay using flow cytometry with magnetic-fluorescent microspheres for detecting NAbs against diverse SARS-CoV-2 variants. The assay is rapid, reliable, and 35-fold more sensitive than Luminex technology. Our results highly correlated with the IgG serological assay (R = 0. 90), the FDA-approved cPass sVNT assay (R = 0. 92), pseudovirus-based neutralization assay (R = 0. 96, 0. 66, 0. 65), and live virus-based neutralization assay (R = 0. 79, 0. 64). When applied to 56 healthy individuals receiving third-dose vaccines (18 CoronaVac; 38 ZF2001) and 35 HIV patients with breakthrough infection of COVID-19 (16 with CD4+ 500 cells/μL), results showed that the Omicron BA. 1-BA. 5 variants exhibited significant resistance to inactivated vaccines in healthy individuals. In HIV patients, the breakthrough infection of Omicron BA. 5.2 or BF. 7 variants can induce broad neutralizing activity to non-Omicron and Omicron variants together with vaccination. Notably, the levels of NAbs against most of the SARS-CoV-2 variants are much lower in the decreased immunity of HIV patients (CD4+ 500 cells/μL), indicating that maintenance of the immune system is crucial for NAb production. Altogether, our high-throughput proteomics platform represents a powerful tool for the detection of bNAbs in the population and may inform the development of more effective COVID-19 vaccines and vaccination strategies in the future.

Semantics

Original Article