sCD23 Human
(a) Analysis by RP-HPLC.
(b) Analysis by SDS-PAGE.
Description
Product Specs
Product Science Overview
CD23 is initially expressed as a 45-kDa type II membrane protein. It contains a lectin head domain that harbors the IgE binding site and a C-terminal tail in the extracellular sequence . CD23 is assembled into a trimer, the predominant form in the B cell membrane, by way of an α-helical coiled-coil stalk that links the three lectin head and tail domains to their transmembrane and cytoplasmic sequences . The soluble form of CD23 is a 25-kDa fragment that can be found in serum, plasma, and urine .
Functionally, CD23 is involved in B cell growth and differentiation, and IgE production. The soluble form of CD23 is a potent mitogenic factor, meaning it can stimulate cell division . Diseases associated with CD23 dysfunction include chronic conjunctivitis and chronic lymphocytic leukemia .
Soluble CD23 plays a crucial role in the regulation of IgE synthesis. When purified tonsil B cells are incubated with interleukin-4 (IL-4) and anti-CD40 to induce class switching to IgE in vitro, mCD23 is upregulated, and sCD23 accumulates in the medium prior to IgE synthesis . This indicates that IgE synthesis is positively controlled by sCD23. Recombinant trimeric sCD23 enhances IgE synthesis even when endogenous mCD23 is protected from cleavage .
Recombinant human sCD23 is produced using an expression system, typically in Escherichia coli (E. coli). The recombinant protein is a 19.2 kDa non-glycosylated protein containing 172 amino-acid residues . It is purified to a high degree, with a purity of ≥ 96% by SDS-PAGE gel and HPLC analyses . The recombinant form is used in various research applications, including the study of B cell growth, differentiation, and IgE production .
Soluble CD23 has significant implications in clinical and research settings. It is used as a marker for prognosis in diseases such as chronic lymphocytic leukemia . Additionally, the anti-CD23 monoclonal antibody lumiliximab has been shown to downregulate IgE synthesis by human B cells in vitro and reduce human serum IgE levels in clinical trials . This provides proof of principle that mCD23 is a valid target for therapy in conditions associated with elevated IgE levels, such as allergic asthma .
