Rapid and Safe Neutralization Assay for Circulating H5N1 Influenza Virus in Dairy Cows

Rapid and safe neutralization assays are required for highly pathogenic avian influenza viruses, including a clade 2.3.4.4b H5N1 subtype recently found in cows. Here, we report a neutralization assay using luminescent virus-like particles. This assay has lower biosafety requirements and provides a larger dynamic range than conventional methods. We applied this technique to evaluate the cross-reactivity of neutralizing antibodies induced by clade 2.3.4.4b candidate vaccine viruses (CVVs) with the cow-derived H5N1 virus. Our findings indicate that these CVVs share antigenic characteristics with the cow-derived H5N1 virus, suggesting the potential efficacy of vaccines developed using these CVVs.