Epitope Binning: A Critical Step In Antibody Selection

Where does epitope binning fit in the antibody development process?

Therapeutic monoclonal antibodies (mAb) are a large and growing part of the biopharmaceutical market, accounting for over 50% of therapeutic protein sales. It is critical during the development of new vaccines, therapeutic Abs, and diagnostic tools that mAbs with the appropriate affinity, specificity, and biophysical properties are selected.

Epitope binning is used to characterize the binding of mAbs to a target protein, the antigen. In epitope binning, mAbs specific to the same target protein are tested pairwise against all mAbs in a set to assess whether they block one another’s binding to a specific site of the antigen or not. The mAbs that block binding to the same epitope are “binned” together.

Early stage Ab drug development efforts often generate many leads, which means that it is critical to select the best candidates for further investigation. mAbs within the same bin often function similarly, so epitope bins can narrow down the choices to fewer candidates for investigators to choose from. In addition, although the Abs within a bin bind to the same antigen, they may have different mechanisms of action, which is critical for treating some types of cancers and infectious diseases. Epitope diversity is also important to broaden intellectual property (IP) protection, i.e., see review of current best practices for the use of epitope information.

This article discusses how SPR is used to characterize closely related “bins” of mAbs targeting the same epitope of the target protein and how the selection process is used to develop new vaccines, therapeutic antibodies, and diagnostic tools.