Utilizing ELISA to monitor protein-protein interaction.

Enzyme-linked immunosorbent assay (ELISA) is a commonly used method in analyzing biomolecular interactions. As a rapid, specific, and easy-to-operate method, ELISA has been used as a research tool as well as a widely adopted diagnostic method in clinical settings and for microbial testing in various industries. Inhibition ELISA is a one-site binding analysis method, which can monitor protein-protein interactions in solution as opposed to more commonly used sandwich ELISA in which the analyte capture step is required on a solid surface either through specific capture or through passive adsorption. Here, we introduce inhibition ELISA procedures, using a recombinant viral protein as an example, with emphasis on how inhibition ELISA could be used to probe subtle protein conformational changes in solution impacting protein-protein binding affinity. Inhibition ELISA is used to probe one binding site at a time for binding partners in solution with unrestricted conformation. The assay can be performed in a quantitative manner with a serially diluted analyte in solution for solution antigenicity or binding activity assessment.