Optimisation of a multiplexed, high throughput assay to measure neutralising antibodies against SARS-CoV-2 variants.

A multiplexed, lentivirus-based pseudovirus neutralisation assay (pVNT) was developed for high-throughput measurement of neutralising antibodies (nAbs) against three distinct SARS-CoV-2 spike variants. Intra-assay variability was minimised by optimising the plate layout and determining an optimal percentage transduction for the pseudovirus inoculum. Comparison of monoclonal antibody EC50 titres between single and multiplexed pVNT assays showed no significant differences, indicating reliability of the multiplexed assay. Evaluation of convalescent human sera confirmed assay validity, with consistent fold drops in EC50 for variant pseudoviruses relative to the ancestral strain observed across single and multiplexed assays. This multiplexed pVNT provides a reliable tool for assessing nAb responses against SARS-CoV-2 variants and could be used to accelerate preclinical vaccine assessment in preparation for the next coronavirus pandemic.