THE INFLUENCE OF THE HINGE REGION LENGTH IN BINDING OF HUMAN-IGG TO HUMAN FC-GAMMA RECEPTORS

Interactions between human IgG with human Fc gamma RI and Fc gamma RII a (R131) were studied to investigate the role of the hinge region of I gG3 and IgG1 in the binding of the antibodies to Fc gamma R. II was fo und that a hinge deletion mutant of IgG3 (IgG3 m15) was reduced in its ability to bind to Fc gamma RI and Fc gamma RIIa but was more potent at activating ADCC by activated lymphocytes (Fc gamma RIIIa-mediated), compared to the wild-type version of IgG3. The human IgG1 allotype Gl m(a,z) was more efficient at binding to Fc gamma RI than the two IgG3 antibodies rested. The IgG1 and IgG3 wild type antibodies were better able to bind to Fc gamma RII than the hinge deletion mutant: version o f IgG3. The data suggest a role for the hinge region in influencing Fc gamma R mediated effector functions in IgG3. (C) American Society for Histocompatibility and Immunogenetics, 1998. Published by Elsevier Sc ience Inc.