Measurement of kinetic binding constants of viral antibodies using a new biosensor technology

Association (ka) and dissociation (kd) rate constants of three monoclonal antibodies raised against tobacco mosaic virus were determined using a biosensor technique based on surface plasmon resonance (BIAcore, Pharmacia). Dissociation rates were constant over the 4-400 nM antibody concentration range whereas apparent association rates decreased over this range probably due to an increased saturation level of the antigen. Affinity constants K calculated from the ratio of ka/kd were in reasonable agreement with values obtained under equilibrium conditions by two standard methods based on enzyme immunoassay.