Functional characteristics of the high affinity IgG receptor, FcγRI

J Immunol. 2011 Mar 1;186(5):2699-704. doi: 10.4049/jimmunol.1003526.


IgG FcRs are important mediators of immunity and play a key role during Ab-based immunotherapy. Within the leukocyte IgG receptor family, only FcγRI is capable of IgG binding with high affinity. FcγRI exists as a complex of a ligand binding α-chain and an FcR γ-chain. The receptors' α-chain can, furthermore, elicit several functions independent of the ITAM-bearing FcR γ-chain. Functional implications of high-affinity IgG binding and mechanisms underlying FcR γ-chain-independent signaling remain unclear to this day. In this paper, we provide an overview of past literature on FcγRI and address the implications of recently described interactions between cytosolic proteins and the FcγRI α-chain, as well as cytokine-enhanced FcγRI immune complex binding. Furthermore, an analysis of potential polymorphisms within the FCGR1A gene is provided.

Publication types

  • Comparative Study
  • Review

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antigen Presentation / genetics
  • Antigen Presentation / immunology
  • Antigen-Antibody Complex / chemistry
  • Antigen-Antibody Complex / genetics
  • Antigen-Antibody Complex / physiology
  • Binding Sites, Antibody* / genetics
  • Disease Models, Animal
  • Humans
  • Molecular Sequence Data
  • Protein Binding / genetics
  • Protein Binding / immunology
  • Protein Structure, Tertiary / genetics
  • Receptors, IgG / chemistry
  • Receptors, IgG / genetics
  • Receptors, IgG / physiology*


  • Antigen-Antibody Complex
  • FCGR1A protein, human
  • Fcgr1 protein, mouse
  • Receptors, IgG