Immune regulation by Fcα/μ receptor (CD351) on marginal zone B cells and follicular dendritic cells

Immunol Rev. 2015 Nov;268(1):288-95. doi: 10.1111/imr.12345.


Although both Fcα/μ receptor (Fcα/μR) and polymeric Ig receptor (poly-IgR) are Fc receptors for IgA and IgM and are functionally and genetically related, the expression profile of Fcα/μR is unique. Unlike poly-IgR, Fcα/μR is expressed on marginal zone (MZ) B cells and follicular dendritic cells, suggesting that Fcα/μR plays an important role in humoral immune responses. Fcα/μR mediates endocytosis of the IgM immune complex (IC). Recent research demonstrated that Fcα/μR downregulated retention of the IgM IC with a T-independent (TI) antigen on MZ B cells and follicular dendritic cells due to endocytosis of the IgM IC, suppressing germinal center formation, affinity maturation, and memory B-cell generation in response to TI antigen challenge. In addition, Fcα/μR physically associates with Toll-like receptor 4 (TLR4) and augments TLR4 oligomerization and signaling in MZ B cells upon lipopolysaccharide (LPS) challenge, leading to increased proinflammatory cytokine production by MZ B cells. Thus, Fcα/μR is a unique Fc receptor that is involved in humoral immune responses and inflammation.

Keywords: Fc receptor; Fcα/μ receptor; IgA; IgM; follicular dendritic cells; marginal zone B cells.

Publication types

  • Review

MeSH terms

  • Animals
  • Antigen-Antibody Complex / metabolism
  • B-Lymphocytes / immunology*
  • B-Lymphocytes / metabolism*
  • Dendritic Cells, Follicular / immunology*
  • Dendritic Cells, Follicular / metabolism*
  • Endocytosis
  • Epitopes, T-Lymphocyte / immunology
  • Gene Expression
  • Germinal Center / immunology*
  • Germinal Center / metabolism*
  • Humans
  • Immunity, Humoral
  • Immunoglobulin A / immunology
  • Immunoglobulin A / metabolism
  • Immunoglobulin Fc Fragments / immunology
  • Immunoglobulin Fc Fragments / metabolism
  • Immunoglobulin M / immunology
  • Immunoglobulin M / metabolism
  • Immunomodulation*
  • Inflammation / genetics
  • Inflammation / immunology
  • Inflammation / metabolism
  • Multigene Family
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Receptors, Fc / chemistry
  • Receptors, Fc / genetics
  • Receptors, Fc / metabolism*


  • Antigen-Antibody Complex
  • Epitopes, T-Lymphocyte
  • Immunoglobulin A
  • Immunoglobulin Fc Fragments
  • Immunoglobulin M
  • Receptors, Fc