Description
CD21 is a 145 kDa transmembrane glycoprotein that is expressed on mature B cells, follicular dendritic cells, a subset of immature thymocytes and on some epithelial cells. CD21 is also known as the C3d Receptor, Complement Receptor 2 (CR2), and the Epstein-Barr Virus receptor, (EBV-R). CD21 is part of a large signal-transduction complex that also includes CD19, CD81 and Leu13. CR2 serves as a receptor for the activation fragments of complement component C3, i.e. C3d, iC3d, and C3dg and C3d-bound antigens and plays a central role in the immune response by amplifying B-cell activation and proliferation. CR2 is also the receptor for EBV by binding its surface glycoprotein gp350/220. Anti-human CR2 hybridomas were generated from Cr2-/-mice (lacking the cr2 gene, that encodes CR2 and CR1 in mice) immunized with the recombinant protein representing the first two amino-terminal short consensus repeats (SRC) of human CR2, SCR1-2. Both the C3d and EBV binding sites of hu CR2 were localized to these sites. Clone 1048 has been reported to specifically react with CR2-expressing cells and to inhibit CR2 interactions with C3 fragments or the EBV surface protein, gp350/220.
BD® CompBeads can be used as surrogates to assess fluorescence spillover (compensation). When fluorochrome conjugated antibodies are bound to BD® CompBeads, they have spectral properties very similar to cells. However, for some fluorochromes there can be small differences in spectral emissions compared to cells, resulting in spillover values that differ when compared to biological controls. It is strongly recommended that when using a reagent for the first time, users compare the spillover on cells and BD® CompBeads to ensure that BD® CompBeads are appropriate for your specific cellular application.
Store undiluted at 4°C and protected from prolonged exposure to light. Do not freeze. The monoclonal antibody was purified from tissue culture supernatant or ascites by affinity chromatography. The antibody was conjugated to the dye under optimum conditions that minimize unconjugated dye and antibody.
1. When using high concentrations of antibody, background binding of this dye to erythroid fragments produced by ammonium chloride-based lysis, such as with BD Pharm Lyse™ Lysing Buffer (Cat. No. 555899), has been observed when the antibody conjugate was present during the lysis procedure. This may cause nonspecific staining of target cells, such as leukocytes, which have bound the resulting erythroid fragments. This background can be mitigated by any of the following: titrating the antibody conjugate to a lower concentration, fixing samples with formaldehyde, or removing erythrocytes before staining (eg, gradient centrifugation or pre-lysis with wash). This background has not been observed when cells were lysed with BD FACS™ Lysing Solution (Cat. No. 349202) after staining.
2. Researchers should determine the optimal concentration of this reagent for their individual applications.
3. The production process underwent stringent testing and validation to assure that it generates a high-quality conjugate with consistent performance and specific binding activity. However, verification testing has not been performed on all conjugate lots.
4. Please refer to www.bdbiosciences.com/us/s/resources for technical protocols.
5. Please observe the following precautions: Absorption of visible light can significantly alter the energy transfer occurring in any tandem fluorochrome conjugate; therefore, we recommend that special precautions be taken (such as wrapping vials, tubes, or racks in aluminum foil) to prevent exposure of conjugated reagents, including cells stained with those reagents, to room illumination.
6. An isotype control should be used at the same concentration as the antibody of interest.
7. Caution: Sodium azide yields highly toxic hydrazoic acid under acidic conditions. Dilute azide compounds in running water before discarding to avoid accumulation of potentially explosive deposits in plumbing.
8. Please refer to http://regdocs.bd.com to access safety data sheets (SDS).
9. For fluorochrome spectra and suitable instrument settings, please refer to our Multicolor Flow Cytometry web page at www.bdbiosciences.com/colors.
10. Since applications vary, each investigator should titrate the reagent to obtain optimal results.
11. Cy is a trademark of Global Life Sciences Solutions Germany GmbH or an affiliate doing business as Cytiva.
