Practical considerations of the ability of monoclonal antibodies to detect antigenic differences between closely related variants

This report describes an investigation of the abilities of different immunoassays to detect differences in affinities between related antigens for particular monoclonal antibodies. Nine different monoclonal antibodies were used and 6 strains of influenza virus represented closely related antigens. Parameters defining assay sensitivity were estimated experimentally for each antibody in 4 different immunoassays. Predicted failures of particular assays to detect differences in antigen affinities, based on these parameters, were demonstrated. One assay method failed to detect heteroclitic activity of 1 antibody which was clearly evident in the other 3 assays. As well as supporting theoretical models of assay sensitivity derived in the preceding paper the experiments demonstrated a significant effect of antibody subclass.