Capture of the human IgG1 antibodies by protein A for the kinetic study of h-IgG/FcγR interaction using SPR-based biosensor technology.

Surface plasmon resonance (SPR) is a key technology to evaluate IgG effector functions in vitro involving binding to Fcgamma receptors (FcγR). We describe here the chemical coupling of protein A to a sensor chip. IgGs prepared either from purified antibodies or from crude cell media supernatants are captured by the protein A and are used as the ligand. Soluble forms of FcγRs are injected at different concentrations and are used as the analyte. This setup allows the definition of the kinetic rates of binding of the FcγRI (high affinity) or the FcγRIIIa (low affinity) on the Fc domain of IgGs.