Product Specifications for Recombinant Human CD23/Fc epsilon RII Protein, CF
Mouse myeloma cell line, NS0-derived human CD23/Fc epsilon RII protein Asp48-Ser321, with an N-terminal 9-His tag
>90%, by SDS-PAGE under reducing conditions and visualized by silver stain
<0.10 EU per 1 μg of the protein by the LAL method.
N-terminal sequence Analysis
Predicted Molecular Mass
41 kDa, reducing conditions
Measured by its binding ability in a functional ELISA. Immobilized rhCD23 at 2 µg/mL (100 µL/well) can bind human IgE with a linear range of 0.015-1 µg/mL.
Formulation, Preparation and Storage
What does CF mean?
CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our
Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant
protein to be stored at a more dilute concentration.
The carrier free version does not contain BSA.
What formulation is right for me?
In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or
as an ELISA standard.
In contrast, the carrier free protein is recommended for applications, in which the presence of BSA
Lyophilized from a 0.2 μm filtered solution in PBS.
Reconstitute at 100 μg/mL in sterile PBS.
The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below.
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.
3 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).
Kijimoto-Ochiai, S. (2002) Cell. Mol. Life Sci. 59:648.
Heyman, B. (2000) Annu. Rev. Immunol. 18:709.
Bajorath, J. and A. Aruffo (1996) Protein Sci. 5:240.
Drickamer, K. (1993) Curr. Opin. Struct. Biol. 3:393.
Drickamer, K. (1999) Curr. Opin. Struct. Biol. 9:585.
Yokota, A. et al. (1988) Cell 55:611.
Ludin, C. et al. (1987) EMBO J. 6:109.
Ikuta, K. et al. (1987) Proc. Natl. Acad. Sci. USA 84:819.
Kikutani, H. et al. (1986) Cell 47:657.
Letellier, M. et al. (1988) J. Immunol. 141:2374.
Hibbert, R.G. et al. (2005) J. Exp. Med. 202:751.
Beavuil, A.J. et al. (1992) Proc. Natl. Acad. Sci. USA 89:753.
Yokota, A. et al. (1992) Proc. Natl. Acad. Sci. USA 89:5030.
Belleau, J.T. et al. (2005) Clin. Mol. Allergy 3:6.
Tu, Y. et al. (2005) Gastroenterology 129:928.
Marolewski, A.E. et al. (1998) Biochem. J. 333:573.
Fourie, A.M. et al. (2003) J. Biol. Chem. 278:30469.
Karagiannis, S.N. et al. (2001) Immunology 103:319.
Aubry, J-P. et al. (1992) Nature 358:505.
Sarfati, M. and G. Delespeese (1988) J. Immunol. 141:2195.
Lecoanet-Henchoz, S. et al. (1995) Immunity 3:119.
Fc epsilon Receptor II
Entrez Gene IDs
2208 (Human); 14128 (Mouse); 171075 (Rat)
BLAST-2, C-type lectin domain family 4, member J, CD23, CD23A, CD23CD23 antigen, CLEC4J, CLEC4JC-type lectin domain family 4 member J, FCE2Fc fragment of IgE, low affinity II, receptor for (CD23A), FCER2, Fc epsilon RII, Fc fragment of IgE, low affinity II, receptor for (CD23), FceRII, Fcer2a, IGEBF, Immunoglobulin E-binding factor, Ly-42, Lymphocyte IgE receptor, fc-epsilon-RII, low affinity immunoglobulin epsilon Fc receptor
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