Defining the immunological phenotype of Fc receptor-like B (FCRLB) deficient mice: Confounding role of the inhibitory FcγRIIb.

Academic Article


  • Fc receptor-like A (FCRLA) and FCRLB have homology to the transmembrane FCRL family members (FCRL 1-6) and to the conventional receptors for the Fc portion of immunoglobulin, but uniquely are cytosolic proteins expressed in B cells. Here we describe the phenotype of Fcrlb-gene targeted mice. B cell development and in vitro responses are normal; however, antibody responses to a T-dependent antigen are elevated. The gene encoding the inhibitory FcγRIIb is located nearby Fcrlb. Although Fcrlb-gene targeting had no effect on the function or basal expression of FcγRIIb, its expression was reduced following activation. This abnormal regulation was due to co-inheritance of Fcgr2b and the mutant Fcrlb allele from the 129 ES cells. A promoter polymorphism in the 129/Sv Fcgr2b allele results in diminished upregulation of FcγRIIb following B cell activation. Thus, we speculate that the enhanced antibody response seen in the FCRLB-deficient mice may be due to the Fcgr2b promoter.
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  • Animals, Antibodies, Anti-Idiotypic, Antibodies, Antinuclear, Antibody Formation, B-Lymphocytes, Cell Count, Cell Proliferation, Gene Expression, Immunoglobulin Fab Fragments, Lipopolysaccharides, Lymphocyte Activation, Mice, Mice, 129 Strain, Mice, Inbred C57BL, Mice, Knockout, Nitrophenols, Phenylacetates, Polymorphism, Genetic, Promoter Regions, Genetic, Receptors, Fc, Receptors, IgG, Vaccination
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    Author List

  • Masuda K; Mori H; Ohara O; Nakayama M; Wang J-Y; Burrows PD
  • Start Page

  • 24
  • End Page

  • 31
  • Volume

  • 266
  • Issue

  • 1