Fig. 4: Interaction of heme-binding antibodies with human FcRn.

a Real-time binding profiles of selected heme-binding and heme-sensitive Abs to surface-immobilized human recombinant FcRn. The interaction analyses were performed with native and Abs exposed to an excess of hemin. The black lines depict the binding profiles obtained after injection of serial dilutions of monoclonal Abs, native, and after heme exposure (25–0.195 nM). The red lines depict the fits of data obtained by global analysis using the Langmuir kinetic model. All interaction analyses were performed at 25 °C. b Values of the kinetic rate constants of association (top panel), dissociation (middle panel), and equilibrium dissociation constant (bottom panel) for binding of native and heme-exposed monoclonal Abs to FcRn. The kinetics data were obtained after analyses of the real-time interaction profiles shown in (a).