A) Annexin A2 was immobilized on an ELISA plate and incubated with factor H. Factor H bound to the immobilized annexin A2. The experiment was repeated three times, and representative results are shown. B) Surface plasmon resonance was performed. Factor H was immobilized on a CM5 chip and the binding of annexin A2 was evaluated at several different concentrations (3 μM, 1 μM, 333 nM, 111 nM, and 37 nM). Annexin A2 bound to the factor H with a dissociation constant of approximately 7 μM.