Recombinant Human CD23

CD23 (cluster of differentiation 23), also known as Fc epsilon RII (FcεRII), is a type II transmembrane glycoprotein and C-type lectin belonging to the immunoglobulin superfamily, predominantly expressed on mature and activated B cells as well as macrophages, eosinophils, follicular dendritic cells, and platelets. Functionally, CD23 serves as a low-affinity Fc receptor for IgE, playing a central role in regulating IgE-mediated immune responses, allergic reactions, and parasite immunity. Both membrane-bound and soluble forms of CD23 (sCD23) exhibit pleiotropic cytokine-like activities that influence lymphocyte survival, B cell differentiation, and myeloid lineage development.​ CD23’s versatile ligand-binding repertoire includes IgE, CD21, MHC class II, and integrins, highlighting its critical function in immune regulation and potential interactions beyond IgE alone. In the clinical context, CD23 serves as a reliable immunophenotypic marker to distinguish chronic lymphocytic leukemia (CLL), which is CD23-positive, from other B-cell leukemias or lymphomas, such as mantle cell lymphoma. The dynamic regulation of IgE synthesis by CD23—where soluble CD23 upregulates IgE production via CD21, while IgE binding to membrane CD23 suppresses further synthesis—offers important insight into B-cell biology and immunopathogenesis.