Anti-CD23 (Low Affinity Immunoglobulin epsilon Fc Receptor, Fc-epsilon-RII, Lymphocyte IgE Receptor,

The low affinity receptor for IgE, Fce RII is a member of subgroup II of the C-type (Ca2+-dependent) lectin superfamily. Mouse CD23 is a 45-49kD type II transmembrane glycoprotein that binds mouse, but not human, IgE. The longest isoform is 331aa in length and contains a 23aa cytoplasmic domain, a 26aa transmembrane segment, and a 282aa extracellular domain (ECD). The ECD C-type lectin domain binds both protein and carbohydrate, with separate sites for binding IgE, CD21, and B2 and av integrins. Coiled-coil topography within a connecting stalk contributes to oligomerization, which increases IgE affinity. Mouse CD23 shares 88% aa identity with rat CD23 and up to 57% aa identity with isoforms of human, equine, porcine and bovine CD23. Isoforms which vary in the cytoplasmic sequence include the "a" isoform, which begins with the sequence MEENEYS and is constitutively expressed by B cells, and the "b" isoform, which begins with MDTHHT and is induced by IL-4 on a variety of inflammatory cells, B cells and epithelia. The isoforms differentially participate in IgE-mediated endocytosis and phagocytosis. CD23b and two 309aa mouse CD23b isoforms, lacking either exon 5 or 6, also display distinct endocytic properties on intestinal epithelia. Several soluble forms of CD23 are mainly generated by metalloprotease (especially ADAM10) and cysteine protease digestion, although potentially soluble mouse isoforms have also been sequenced. Both soluble and membrane-bound forms of CD23 include the lectin domain and show bioactivity. CD23 binding to monocyte integrins results in oxidative product generation and proinflammatory cytokine release. On human, but not mouse, B cells, sCD23 induces IgE secretion by binding CD21. In both, secreted IgE will bind B cell membrane CD23, rendering it unavailable for cleavage, and thus shutting down IgE production. Applications: Suitable for use in Flow Cytometry. Other applications not tested. Recommended Dilution: Flow Cytometry: 2.5ug labels 10e6 cells, Optimal dilutions to be determined by the researcher. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.