Use of biosensors to characterize recombinant proteins

A new biosensor technology based on surface plasmon resonance (BIAcore, Pharmacia) is described which allows the surface and conformational integrity of a recombinant product to be monitored by measuring the binding characteristics of a panel of monoclonal antibodies. Interactions between the antibodies and the recombinant product are measured in real time in a quantitative and highly reproducible manner. This allows the association and dissociation kinetic rate constants of the antibodies to be calculated and not only the equilibrium binding constant. Besides using antibodies as conformational probes, the biosensor can also be used to measure directly the binding of a recombinant product to its natural biological ligand. Quantitative binding assays using biosensors are a powerful method for assessing the lot-to-lot consistency of recombinant products.