protein_function:
CD23, also known as Fc epsilon RII, or Fc??RII, is the "e;low-affinity"e; receptor for IgE, an antibody isotype involved in allergy and resistance to parasites, and is important in regulation of IgE levels. There are two forms of CD23: CD23a and CD23b. CD23a is present on follicular B cells, whereas CD23b requires IL-4 to be expressed on T-cells, monocytes, Langerhans cells, eosinophils, and macrophages. As part of a mapping of multiple probes to specific bands on chromosome 19 by fluorescence in situ hybridization, the FCE2 gene was assigned to 19p13.3. CD23(FCE2) is a key molecule for B-cell activation and growth. It is the low-affinity receptor for IgE. The truncated molecule can be secreted, then functioning as a potent mitogenic growth factor.
