Detects human CD23/Fc epsilon RII in direct ELISAs and Western blots.
Monoclonal Mouse IgG1 Clone # 138628
Protein A or G purified from hybridoma culture supernatant
Mouse myeloma cell line NS0-derived recombinant human CD23/Fc epsilon RII Met150-Ser321 Accession # P06734
Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose. *Small pack size (SP) is supplied as a 0.2 µm filtered solution in PBS.
Recombinant Human CD23/Fc epsilon RII (Catalog # 123-FE)
0.25 µg/106 cells
Blockade of Receptor-ligand Interaction
In a functional ELISA, 0.5-2.5 µg/mL of this antibody will block 50% of the binding of 500 ng/mL of human IgE to immobilized Recombinant Human CD23/Fc epsilon RII (Catalog # 123-FE) coated at 2 µg/mL (100 µL/well). At 20 μg/mL, this antibody will block >90% of the binding.
Ready to be labeled using established conjugation methods. No BSA or other carrier proteins that could interfere with conjugation.
Please Note: Optimal dilutions should be determined by each laboratory for each application. General Protocols are available in the Technical Information section on our website.
Detection of CD23/Fc epsilon RII in Human Blood Lymphocytes by Flow Cytometry. Human peripheral blood lymphocytes were stained with Mouse Anti-Human CD19 APC‑conjugated Monoclonal Antibody (Catalog # FAB4867A) and either (A) Mouse Anti-Human CD23/Fc epsilon RII Monoclonal Antibody (Catalog # MAB123) or (B) Mouse IgG1 Isotype Control (Catalog # MAB002) followed by Phycoerythrin-conjugated Anti-Mouse IgG Secondary Antibody (Catalog # F0102B). View our protocol for Staining Membrane-associated Proteins.
Preparation and Storage
Reconstitute at 0.5 mg/mL in sterile PBS.
The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below. *Small pack size (SP) is shipped with polar packs. Upon receipt, store it immediately at -20 to -70 °C
Stability & Storage
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70 °C as supplied.
1 month, 2 to 8 °C under sterile conditions after reconstitution.
6 months, -20 to -70 °C under sterile conditions after reconstitution.
Background: CD23/Fc epsilon RII
CD23 (also named B cell differentiation antigen) is a member of subgroup II of the C-type (Ca++-dependent) lectin superfamily (1‑5). Human CD23 is a 47 kDa type II transmembrane glycoprotein that is expressed by a wide variety of cell types (6‑10). The full-length receptor is 321 amino acids (aa) in length and contains a 274 aa extracellular region, a 26 aa transmembrane segment, and a 21 aa cytoplasmic domain. The extracellular region contains a C-type lectin domain and a connecting stalk with coiled-coil topography (3, 11). The lectin domain binds both protein and carbohydrate in an apparently Ca++ independent manner (11). The coiled-coil region contributes to oligomerization (11, 12). The lectin domain in human CD23 (aa 162‑284) is 64%, 62% and 68% aa identical to the lectin domains in mouse, rat and bovine CD23, respectively. In the cytoplasmic region, two FC isoforms exist which arise from alternate start sites (6, 12). The “a” (or long) isoform begins with the sequence MEEGQYS and is constitutively expressed by B cells. It is believed to participate in IgE-mediated endocytosis (13). The “b” (or short) isoform begins with MNPPSQ and is induced on a wide variety of cell types by IL-4 (6). Fcb reportedly contributes to IgE-mediated phagocytosis (13). Fcb expressing cells include eosinophils, monocytes, visceral smooth muscle and intestinal epithelium (6, 14, 15). At least four soluble forms of CD23 are known to exist. They range in molecular weight from 25 kDa to 37 kDa, with the 25 kDa form predominating in sera (16). Soluble CD23 (sFc) is generated by metalloprotease (ADAM8; ADAM15; ADAM28) and cysteine-protease activity (16‑18). Cleavage usually occurs between aa 150‑160 (7, 8). It is unclear if sequential metalloprotease-cysteine protease activity is necessary for the generation of all soluble forms. Both soluble and membrane-bound CD23 show bioactivity. Ligands for CD23 include CD21, IgE, CD11b, and CD11c (19‑21). CD23 binding to CD11b and Cd11c on monocytes results in oxidative product generation and proinflammatory cytokine release (21). On B cells, sCD23 induces IgE secretion by binding CD21. Conversely, secreted IgE will, in turn, bind B cell membrane CD23, rendering it unavailable for cleavage, and thus shutting down IgE production (11).
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Fc epsilon Receptor II
Entrez Gene IDs:
2208 (Human); 14128 (Mouse); 171075 (Rat)
BLAST-2; CD23; CD23A; CD23CD23 antigen; CLEC4J; CLEC4JC-type lectin domain family 4 member J; C-type lectin domain family 4, member J; Fc epsilon RII; Fc fragment of IgE, low affinity II, receptor for (CD23); FCE2Fc fragment of IgE, low affinity II, receptor for (CD23A); fc-epsilon-RII; FCER2; Fcer2a; FceRII; IGEBF; Immunoglobulin E-binding factor; low affinity immunoglobulin epsilon Fc receptor; Ly-42; Lymphocyte IgE receptor
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