Figure 6. The IgE-binding affinity of UB-221 and ligelizumab on SPR.

Kinetic analyses on SPR of IgE binding to the anti-IgE mAbs UB-221, ligelizumab (Creative Biolabs, TAB755), and omalizumab were performed on SPR. IgG Fc antibodies were first covalently coupled to the surface sensor chip, on which the diluted anti-IgE antibodies were captured. The Expi293-expressed human full-length IgE at 0.312–50 nM was injected and the dissociation was measured under constant buffer flow. The resulting equilibrium dissociation rate constant (K_D, binding affinity), association rate constant (k_a), and dissociation rate constant (k_d) are presented in the table.