Characterizing pH-Dependent Interactions Between Immunoglobulin and the Neonatal Fc Receptor Using Surface Plasmon Resonance.

The internalization of antibody via pinocytosis and its pH-dependent interaction with the neonatal Fc receptor (FcRn) play crucial roles in antibody recycling within circulation. To achieve an optimal half-life, the binding of antibodies to FcRn at acidic pH and their release at physiological pH must be carefully characterized. Here, we describe the use of surface plasmon resonance (SPR) to measure the affinity of human IgG1 antibodies to human FcRn in both acidic (pH 6.0) and physiological (pH 7.4) conditions to evaluate the recycling behavior of therapeutic candidates.