Evaluation of binding of human serum albumin (HSA) to monoclonal and polyclonal antibody by means of piezoelectric immunosensing technique

Abstract

Binding of human serum albumin (HSA) to its monoclonal and polyclonal antibody was examined by using a quartz crystal immunosensor on which the immobilized monoclonal antibody was exposed to HSA and polyclonal antibody stepwise. The association constants and rate constants of the respective steps of immunoreactions were estimated from the resonant frequency shifts at steady state and the time course of resonant frequency. The binding of HSA to the polyclonal antibody (second step) was shown to be much weaker and slower than that to the monoclonal antibody (first step), probably owing to the steric hindrance and orientation effects of the HSA already bound to the immobilized monoclonal antibody.