Human CD21 ELISA Assay


The Human CD21 ELISA Assay is to be used for the in-vitro quantitative determination of CD21 in human serum, plasma, buffered solutions or cell culture medium. The assay recognizes natural CD21. The Eagle Biosciences Human CD21 ELISA Assay kit is for Research Use Only.

SKU: C2131-K01 Categories: , ,

Human CD21 ELISA Assay

The Human CD21 ELISA Assay is For Research Use Only

Size: 1×96 wells
Sensitivity: <3 U /ml
Dynamic Range: 3.12 U / ml – 100 U / ml
Incubation Time: 1h 45min
Sample Type: Serum, Plasma, Cell Culture
Sample Size: 100 µl
Alternative Name: EBV receptor, CR2, C3Dd Receptor

Specimen collection, processing & storage
Cell culture supernatants, serum, plasma or other biological samples will be suitable for use in the assay. Remove serum from the clot or red cells, respectively, as soon as possible after clotting and separation.
Cell culture supernatants: Remove particulates and aggregates by spinning at approximately 1000 x g for 10 min.
Serum: Avoid any unintentional stimulation of the cells by the procedure. Use pyrogen/endotoxin free collecting tubes. Serum should be removed rapidly and carefully from the red cells after clothing. For that, after clothing, centrifuge at approximately 1000 x g for 10 min and remove serum.
Plasma: EDTA, citrate and heparin plasma can be assayed. Spin samples at 1000 x g for 30 min to remove particulates. Harvest plasma.
Storage: If not analyzed shortly after collection, samples should be aliquoted (250-500μl) to avoid repeated freeze-thaw cycles and stored frozen at –70°C. Avoid multiple freeze-thaw cycles of frozen specimens.

Assay Principle

The CD21 Kit is a solid phase sandwich Enzyme Linked-Immuno- Sorbent Assay (ELISA). A monoclonal antibody specific for CD21 has been coated onto the wells of the microtiter strips provided. Samples, including standards of known CD21 concentrations and unknowns are pipetted into these wells.  During the first incubation, the CD21 antigen and a biotinylated monoclonal antibody specific for CD21 are simultaneously incubated.  After washing, the enzyme (streptavidin-peroxydase) is added. After incubation and washing to remove all the unbound enzyme, a substrate solution is added to induce a coloured reaction product. The intensity of this coloured product is directly proportional to the concentration of CD21 present in the samples.

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Additional Information

Assay Background

CD21 is the receptor of C3Dd in the complement system. It is involved in the transport of immune complexes. CD21 is produced by B lymphocytes, T lymphocytes, pharyngeal epithelial cells, astrocytes and spleen follicular dendritic cells. Epstein-Barr virus uses complement receptor 2 for cell entry. CD21 is glycosylated.

Assay Procedure

  1. Add 100μl of each standard, sample and zero (standard diluent) in duplicate to appropriate number of wells
  2. Add 50μl of diluted biotinylated anti-CD21 to all wells
  3. Cover with a plastic plate cover and incubate at room temperature (18 to 25°C) for 1 hours
  4. Remove the cover and wash the plate
  5. Add 100μl of Streptavidin-HRP solution into all wells
  6. Cover with a plastic plate cover and incubate at room temperature (18 to 25°C) for 30 min
  7. Repeat wash step 5.
  8. Add 100μl of ready-to-use TMB Substrate Solution into all wells
  9. Incubate in the dark for 10-20 minutes* at room temperature. Avoid direct exposure to light by wrapping the plate in aluminium foil
  10. Add 100μl of H2SO4:Stop Reagent into all wells

Typical Standard Curve

Package Insert

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