Human Low Affinity Immunoglobulin Epsilon Fc Receptor (FCER2) Protein

Background

FCER2, also known as CD23, is a low-affinity receptor for the Fc region of Immunoglobulin E (IgE). It is an important protein involved in the regulation of IgE-mediated immune responses and plays a key role in allergy, asthma, and immune regulation. FCER2 was first recognized for its role in B cell differentiation and later found to be expressed in several other immune cell types, including monocytes, eosinophils, dendritic cells, and macrophages. The interaction of CD23 with IgE is critical in the regulation of IgE levels and in modulating allergic responses. Unlike Fc epsilon receptor I (FCERI), which is a high-affinity receptor for IgE and is found on mast cells and basophils, CD23 has a much lower affinity for IgE and is expressed predominantly on B cells. This difference in affinity and cellular distribution allows CD23 to play a different role in immune regulation, particularly in controlling the production of IgE and mediating the interaction between IgE and antigen-presenting cells.