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P2024
Label-Free Antibody Screening Sandwich Assay Using the Corning Epic® System
Presenter Jeffery Scibek, Corning Incorporated, USA
Additional Authors: Arron S. Xu, Klaus Kaluza, Anthony G. Frutos
Antibody therapeutics represent the single fastest growing area of drug discovery and development.  There are now more than 20 approved antibody therapeutics on the market with hundreds more in clinical trials and preclinical development.  As a result of the increased interest in antibody therapeutics, there is currently a need for new tools to identify candidate antibodies as early in the drug discovery process as possible.  These new tools must be sensitive enough to detect antibody-antigen interactions in complex biological samples and they must be high-throughput in order to screen the large number of hybridoma samples being generated for antibody discovery.A label-free antibody sandwich assay was developed on the Corning® Epic® System to characterize competing and non-competing antibodies in a complex biological sample.  In these studies, the binding of three monoclonal antibodies against macrophage-colony stimulating factor receptor (M-CSF R) was investigated.  The M-CSF receptor contained an Fc tag and was captured noncovalently via an anti-Fc antibody immobilized in the wells of a 384-well Epic® microplate.  Binding of three different antibodies to the immobilized receptor was studied in the absence and presence of serum.  When added individually, each antibody exhibited dose-dependent binding to the receptor.  The assay exhibited a large signal window and a dynamic range from 0.1mg/mL to >10mg/mL in both assay buffer and culture medium containing 10% bovine serum.  To test for competition, antibodies were added either sequentially or in batches to M-CSF R.  The expected competition was observed when antibodies were added to the receptor either sequentially or in batch mode in the presence and absence of serum.  Two of the antibodies were shown to compete for the same epitope on M-CSF R.  The third antibody showed binding to a different epitope on the receptor and was non-competitive.  The observed sensitivity of the assay suggests that the Epic® System can be used to screen hybridoma samples in a high-throughput manner with the relatively simple assay format offered by the label-free Epic® technology.