Low affinity immunoglobulin gamma Fc region receptor II-b is a protein that, in humans, is encoded by the FCGR2Bgene. FCGR2B (CD32B) is a "low affinity" receptor for Immunoglobulin G (IgG). Mutation in the gene in humans leads to a lupus phenotype.[1][2] The cytoplasmic part of this receptor contains an immunoreceptor tyrosine-based inhibitory motif, in contrast to the activating isoform, FCGR2A (CD32A).
The inhibitory CD32B is expressed on B cells and myeloid dendritic cells.[3] Ligation of CD32B on B cells downregulates antibody production and may, in some circumstances, promote apoptosis. Co-ligation of CD32B on dendritic cells inhibits maturation and blocks cell activation. CD32B may also be a target for monoclonal antibody therapy for malignancies.[4][5]
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