Label-free epitope binning assays of monoclonal antibodies enable the identification of antigen heterogeneity.

Label-free biosensors are often used in the discovery of therapeutic antibodies to characterize the epitope binding regions of a panel of monoclonal antibodies that target a specific antigen, thus facilitating their organization into epitope groups or "bins". When tested in a pairwise combinatorial manner, two antibodies that compete with one another for binding to a specific antigen may be grouped into the same epitope bin - that is, they recognize similar or overlapping epitopes - whereas two antibodies that bind simultaneously to the antigen are placed into different epitope bins. However, depending on the assay format used, results from such experiments can sometimes contradict one another.

Exploring the dynamic range of the kinetic exclusion assay in characterizing antigen-antibody interactions.

Therapeutic antibodies are often engineered or selected to have high on-target binding affinities that can be challenging to determine precisely by most biophysical methods. Here, we explore the dynamic range of the kinetic exclusion assay (KinExA) by exploiting the interactions of an anti-DKK antibody with a panel of DKK antigens as a model system. By tailoring the KinExA to each studied antigen, we obtained apparent equilibrium dissociation constants (K(D) values) spanning six orders of magnitude, from approximately 100 fM to 100 nM.

The application of target information and preclinical pharmacokinetic/pharmacodynamic modeling in predicting clinical doses of a Dickkopf-1 antibody for osteoporosis.

PF-04840082 is a humanized prototype anti-Dickkopf-1 (Dkk-1) immunoglobulin isotype G(2) (IgG(2)) antibody for the treatment of osteoporosis. In vitro, PF-04840082 binds to human, monkey, rat, and mouse Dkk-1 with high affinity. After administration of PF-04840082 to rat and monkey, free Dkk-1 concentrations decreased rapidly and returned to baseline in a dose-dependent manner.