Fc receptor homolog 3 is a novel immunoregulatory marker of marginal zone and B1 B cells.

Academic Article


  • Two members of the recently identified FcR homolog (FcRH) family in mice demonstrate preferential B cell expression. One of these, FcRH3, encodes a type I transmembrane protein with five extracellular Ig domains and a cytoplasmic tail with a consensus ITIM and a noncanonical ITAM. Analysis of full-length cDNAs from five different mouse strains defines two FcRH3 alleles. A panel of FcRH3-specific mAbs was generated to define its expression pattern and functional potential on B lineage cells. Although poorly detected on the majority of bone marrow or peripheral blood cells, FcRH3 was readily identified on splenic marginal zone (MZ) and MZ precursor B cells, but not on the bulk of newly formed B cells, follicular B cells, germinal center B cells, and plasma cells. In the peritoneal cavity, FcRH3 was found on B1 cells, and not on the majority of B2 cells. Consistent with its possession of an ITIM and ITAM-like sequence, FcRH3 was tyrosine phosphorylated following pervanadate treatment, and its coligation with the BCR inhibited calcium mobilization. These results suggest FcRH3 is a novel immunoregulatory marker of MZ and B1 B lineage cells.
  • Published In


  • Alleles, Animals, Antibodies, Monoclonal, B-Lymphocyte Subsets, Biomarkers, Cells, Cultured, Female, Immunoglobulin Allotypes, Immunologic Factors, Lymphocyte Activation, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Mice, Inbred CBA, Mice, Inbred NZB, Mice, Transgenic, Receptors, Fc, Spleen, Stem Cells
  • Author List

  • Won W-J; Foote JB; Odom MR; Pan J; Kearney JF; Davis RS
  • Start Page

  • 6815
  • End Page

  • 6823
  • Volume

  • 177
  • Issue

  • 10