FITC Mouse Anti-Human CD23 Antibody (S-4517)

CD23, also known as the low-affinity IgE receptor (FcεRII), is a type II transmembrane glycoprotein belonging to the C-type lectin superfamily that plays a pivotal and multifaceted role in regulating immune responses, particularly those involving Immunoglobulin E (IgE). Unlike the high-affinity receptor FcεRI found on mast cells and basophils, CD23 is primarily expressed on B cells, follicular dendritic cells, monocytes, macrophages, eosinophils, and platelets, where it exists in two isoforms: CD23a, which is constitutively expressed on activated B cells, and CD23b, whose expression is induced by interleukin-4 (IL-4). Functionally, CD23 acts as a critical regulator of IgE synthesis through a feedback mechanism where membrane-bound CD23 binds IgE-allergen complexes and presents them to CD21 on B cells to modulate antibody production, while its soluble form (sCD23), generated via proteolytic cleavage by ADAM10, can either enhance or suppress IgE synthesis depending on the context and act as a growth factor for B cells and monocytes. Beyond allergy and asthma pathogenesis, where elevated CD23 levels correlate with disease severity, this protein is involved in antigen presentation, cytokine release (such as IL-6 and TNF-α), cell adhesion via interactions with integrins like CD11b/CD18, and has been implicated in the progression of certain malignancies like chronic lymphocytic leukemia (CLL), making it a significant therapeutic target for monoclonal antibodies aimed at disrupting IgE-mediated pathways or inhibiting tumor growth.