Multiple regions of human FcγRII (CD32) contribute to the binding of IgG

Abstract

The low affinity receptor for IgG, FcγRII (CD32), has a wide distribution on hematopoietic cells where it is responsible for a diverse range of cellular responses crucial for immune regulation and resistance to infection. FcγRII is a member of the immunoglobulin superfamily, containing an extracellular region of two Ig-like domains. The IgG binding site of human FcγRII has been localized to an 8-amino acid segment of the second extracellular domain, Asn154-Ser161. In this study, evidence is presented to suggest that domain I and two additional regions of domain 2 also contribute to the binding of IgG by FcγRII. Chimeric receptors generated by exchanging the extracellular domains and segments..