A high-throughput image cytometry inhibition method to study MERS-CoV antibody interactions

The emergence of Middle East respiratory syndrome coronavirus (MERS-CoV) poses serious threats to global public health and highlights the urgent needs to rapidly identify and characterize potential neutralizing antibodies. For MERS-CoV virions, the spike (S) proteins are present on the surface and mediate viral entry, thus making it the primary target for MERS-CoV vaccine and antibody development. Some of the commonly serological methods like ELISA, biolayer interferometry, and flow cytometry are used to study MERS-CoV antibody binding specificity and function. Those techniques are informative, but limited. In this work, we present a high-throughput image cytometry method for protein binding inhibition assay. The high-throughput screening method used a specifically selected cell type with high DPP4 expression, where optimal seeding density and protein binding conditions were determined in earlier experiments. The ability to detect the inhibition of MERS-CoV S binding to cells was tested in respect to the titration of monoclonal antibodies. The binding inhibition results were comparable with previously published literature for MERS-CoV spike monomer and showed similar patterns as neutralization results. The proposed image cytometry method provides an efficient approach for characterizing potential therapeutic antibodies for combating MERS-CoV that compared favorably with current methods. The ability to rapidly determine direct antibody binding to host cells in a high-throughput manner can be applied to study other pathogen-antibody interactions and thus can impact future research on viral pathogens.