Biolegend, 354929, TotalSeq™-Bn0181 anti-human CD21 Antibody, 10μg

CD21 is a 145 kD transmembrane protein also known as complement C3d receptor (C3dR), complement receptor 2 (CR2), and Epstein-Barr virus receptor. CD21 is expressed on B cells, follicular dendritic cells, subsets of normal thymocytes and T cells, and some epithelial cells. CD21 is the receptor used by Epstein-Barr virus to infect B cells and is also the complement receptor for C3d. CD21 has also been shown to interact with a number of proteins, including CD23, CD19, annexin VI, CD81, iC3b, complement receptor 1 (CR1, CD35), and interferon-alpha 1 (IFN-α1).
10μg
Verified Reactivity: Human
Reported Reactivity: African Green, Baboon, Cynomolgus
Antibody Type: Monoclonal
Host Species: Mouse
Formulation: Phosphate-buffered solution, pH 7.2, containing 0.09% sodium azide and EDTA
Preparation: The antibody was purified by chromatography and conjugated with TotalSeq™-Bn oligomer under optimal conditions.
Concentration: 0.5 mg/mL
Storage & Handling: The antibody solution should be stored undiluted between 2°C and 8°C. Do not freeze.
Application: SB - Quality tested
Recommended Usage: Each lot of this antibody is quality control tested by immunofluorescent staining in formalin-fixed, paraffin-embedded (FFPE) lymphoid tissue, and the oligomer sequence is confirmed by sequencing. TotalSeq™-Bn antibodies are compatible with the 10x Visium CytAssist Gene and Protein Expression Assay. To maximize performance, it is strongly recommended that the reagent be titrated for each application, and that you centrifuge the antibody dilution at 14,000xg at 2 − 8°C for 10 minutes before use. Carefully pipette out the liquid avoiding the bottom of the tube when handling. To determine and optimize dilutions for the addition of Totalseq™-Bn antibodies into pre-designed antibody panels, refer to 10x Genomics Custom Add-on Antibody Optimization guide. Buyer is solely responsible for determining whether Buyer has all intellectual property rights that are necessary for Buyer's intended uses of the BioLegend TotalSeq™ products. For example, for any technology platform Buyer uses with TotalSeq™, it is Buyer's sole responsibility to determine whether it has all necessary third party intellectual property rights to use that platform and TotalSeq™ with that platform.
Application Notes: Additional reported applications (for the relevant formats) include: immunohistochemical staining of acetone-fixed frozen sections4.
Additional Product Notes: TotalSeq™-Bn reagents are designed to profile protein levels following an optimized protocol in spatial transcriptomics. Compatible spatial biology devices (e.g. Imaging System, 10x Genomics Visium Spatial CytAssist Gene and Protein Expression instruments and reagents) and sequencer (e.g. Illumina analyzers) are required. TotalSeq™-B reagents are not compatible with the 10x Genomics Visium system. The complete barcode sequence may be provided upon request. Please contact technical support for more information, or visit TotalSeq™-Bn Reagents for 10x Genomics Visium CytAssist Gene and Protein Assay.
Application References(PubMed link indicates BioLegend citation): Björck P, et al. 1993. Eur. J. Immunol. 23:1771. Frémeaux-Bacchi V, et al. 1996. Eur. J. Immunol. 26:1497. Ling NR, et al. 1995. Clin. Exp. Immunol. 101:369. Wang, C, et al. 2011. BMC Immunol. 12:53. (IHC)
RRID: AB_3083187 (BioLegend Cat. No. 354929)
Structure: Transmembrane protein, multiple SUSHI domains, approximate molecular weight 145 kD
Distribution: Expressed on B cells, follicular dendritic cells, subsets of normal thymocytes and T cells, some epithelial cells
Function: Epstein-Barr virus receptor on B cells used for infection
Interaction: CD23, CD19, complement component 3, annexin VI, CD81, iC3b, complement receptor 1, interferon alpha 1
Ligand/Receptor: C3d, EBV
Cell Type: B cells, Dendritic cells, Epithelial cells, T cells, Thymocytes
Biology Area: Cell Biology, Complement, Costimulatory Molecules, Immunology, Innate Immunity, Neuroinflammation, Neuroscience
Molecular Family: CD Molecules
Antigen References: 1. Kishimoto T, Eds. 1997. Leukocyte Typing VI. Garland Publishing Inc. 2. Moore MD, et al. 1987. Proc. Natl. Acad. Sci. USA 84:9194. 3. Szakonyi G, et al. 2001. Science 292:1725. 4. Weis JJ, et al. 1984. Proc. Natl. Acad. Sci. USA 81:881.
Gene ID: 1380
UniProt: View information about CD21 on UniProt.org
Clone: Bu32
Regulatory Status: RUO
Workshop: V CD21.4, VI CD21.5
Other Names: Complement C3d receptor (C3dR), complement receptor 2 (CR2), Epstein-Barr virus receptor
Isotype: Mouse IgG1, κ
Barcode Sequence: AACCTAGTAGTTCGG
Q: If an antibody clone has been previously successfully used in IBEX in one fluorescent format, will other antibody formats work as well?
A: It’s likely that other fluorophore conjugates to the same antibody clone will also be compatible with IBEX using the same sample fixation procedure. Ultimately a directly conjugated antibody’s utility in fluorescent imaging and IBEX may be specific to the sample and microscope being used in the experiment. Some antibody clone conjugates may perform better than others due to performance differences in non-specific binding, fluorophore brightness, and other biochemical properties unique to that conjugate.
Q: Will antibodies my lab is already using for fluorescent or chromogenic IHC work in IBEX?
A: Fundamentally, IBEX as a technique that works much in the same way as single antibody panels or single marker IF/IHC. If you’re already successfully using an antibody clone on a sample of interest, it is likely that clone will have utility in IBEX. It is expected some optimization and testing of different antibody fluorophore conjugates will be required to find a suitable format; however, legacy microscopy techniques like chromogenic IHC on fixed or frozen tissue is an excellent place to start looking for useful antibodies.
Q: Are other fluorophores compatible with IBEX?
A: Over 18 fluorescent formats have been screened for use in IBEX, however, it is likely that other fluorophores are able to be rapidly bleached in IBEX. If a fluorophore format is already suitable for your imaging platform it can be tested for compatibility in IBEX.
Q: The same antibody works in one tissue type but not another. What is happening?
A: Differences in tissue properties may impact both the ability of an antibody to bind its target specifically and impact the ability of a specific fluorophore conjugate to overcome the background fluorescent signal in a given tissue. Secondary stains, as well as testing multiple fluorescent conjugates of the same clone, may help to troubleshoot challenging targets or tissues. Using a reference control tissue may also give confidence in the specificity of your staining.
Q: How can I be sure the staining I’m seeing in my tissue is real?
A: In general, best practices for validating an antibody in traditional chromogenic or fluorescent IHC are applicable to IBEX. Please reference the Nature Methods review on antibody based multiplexed imaging for resources on validating antibodies for IBEX.