The multiple facets of FcRn in immunity

• Published in: Immunological reviews Vol. 268; no. 1; pp. 253 - 268
• Main Authors: Stapleton, Nigel M., Einarsdóttir, Helga K., Stemerding, Annette M., Vidarsson, Gestur
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01-11-2015
• Subjects: Age Factors; Animals; Antigen Presentation - immunology; FcRn; half-life; Histocompatibility Antigens Class I - chemistry; Histocompatibility Antigens Class I - metabolism; Host-Pathogen Interactions - immunology; Humans; Immunity; Immunoglobulin G - chemistry; Immunoglobulin G - immunology; Immunoglobulin G - metabolism; Models, Molecular; myeloid cells; neonatal Fc receptor; phagocytosis; Phagocytosis - immunology; Protein Binding; Protein Conformation; Protein Transport; Receptors, Fc - chemistry; Receptors, Fc - metabolism; Signal Transduction; Structure-Activity Relationship; Transcytosis; neonatal Fc receptor; FcRn; phagocytosis; myeloid cells; half-life
• ISSN: 0105-2896; 1600-065X
• DOI: 10.1111/imr.12331

Summary
The neonatal Fc receptor, FcRn, is best known for its role in transporting IgG in various tissues, providing newborns with humoral immunity, and for prolonging the half‐life of IgG. Recent findings implicate the involvement of FcRn in a far wider range of biological and immunological processes, as FcRn has been found to bind and extend the half‐life of albumin; to be involved in IgG transport and antigen sampling at mucosal surfaces; and to be crucial for efficient IgG‐mediated phagocytosis. Herein, the function of FcRn will be reviewed, with emphasis on its recently documented significance for IgG polymorphisms affecting the half‐life and biodistribution of IgG3, on its role in phagocyte biology, and the subsequent role for the presentation of antigens to lymphocytes.