Fig. 3.

HcR4 targets Hc to FcγRs. Recombinant ligand-binding domains from FcγRs were immobilized on ELISA plates, and binding of HcR4 or monomeric human IgG was assessed at 5, 10, and 20 μg/ml for low-affinity FcγRs and at 2, 5, and 10 μg/ml for the high-affinity receptor, FcγRI. FcγRIIa (A); FcγRIIb (B); FcγRIIIa-158F (C); FcγRIIIa-158V (D); FcγRI (E). HcR4 has markedly better binding to low-affinity FcγRs than IgG at all concentrations tested. The data presented are from a representative assay of three performed.