• Product name

    Human CD21 ELISA Kit
  • Detection method

  • Precision

    Sample n Mean SD CV%
    Sample A 8 50.25U/ml 2.24 4.45%
    Sample B 8 10.44U/ml 0.46 4.4%
    Sample n Mean SD CV%
    Sample A 8 51.13U/ml 2.29 4.47%
    Sample B 8 10.76U/ml 0.56 5.2%
  • Sample type

    Cell culture supernatant, Serum, Plasma
  • Assay type

    Sandwich (quantitative)
  • Sensitivity

    < 3 U/ml
  • Range

    3.12 U/ml - 100 U/ml
  • Assay time

    1h 45m
  • Assay duration

    Multiple steps standard assay
  • Species reactivity

    Reacts with: Human
  • Product overview

    Abcam’s CD21 Human in vitro ELISA (Enzyme-Linked Immunosorbent Assay) kit is designed for the quantitative measurement of CD21 in Human serum, plasma, buffered solutions and cell culture media.

    A monoclonal antibody specific for CD21 has been coated onto the wells of the microtiter strips provided. Samples, including standards of known CD21 concentrations, control specimens or unknowns are pipetted into these wells. During the first incubation, the standards or samples and a biotinylated monoclonal antibody specific for CD21 are simultaneously incubated. After washing, the enzyme Streptavidin-HRP, that binds the biotinylated antibody is added, incubated and washed. A TMB substrate solution is added which acts on the bound enzyme to induce a colored reaction product. The intensity of this colored product is directly proportional to the concentration of CD21 present in the samples.

    This kit will recognize both endogenous and recombinant Human CD21.

  • Tested applications

    Suitable for: Sandwich ELISAmore details
  • Platform



  • Storage instructions

    Store at +4°C. Please refer to protocols.
  • Components Identifier 2 x 96 tests 1 x 96 tests
    10X Standard Diluent Buffer Black 1 x 25ml 1 x 25ml
    200X Wash Buffer White 2 x 10ml 1 x 10ml
    Biotinylated Antibody Diluent Red 1 x 13ml 1 x 7.5ml
    Biotinylated anti-CD21 antibody Red 2 x 400µl 1 x 400µl
    CD21 Microplate (12 x 8 well strips) 1 x 2 units 1 unit
    CD21 Standard Yellow 4 vials 2 vials
    Chromogen TMB Substrate Solution 1 x 24ml 1 x 11ml
    HRP Diluent Red 1 x 23ml 1 x 23ml
    Stop Reagent Black 2 x 11ml 1 x 11ml
    Streptavidin-HRP 4 x 5µl 2 x 5µl
  • Research areas

  • Relevance

    CD21 also known as complement receptor 2 (CR2), C3d receptor or EBV receptor is a 140 kDa protein. CD21 is a glycosylated type I transmembrane protein consisting of an extracellular face of a series of 15 or 16 CCP domains. CD21 is the receptor for complement components C3d and iC3b as well as the Epstein-Barr virus (EBV) glycoprotein gp350/220. The soluble CD21 (sCD21) was shown to efficiently trigger CD23 signalling pathways in human monocytes. By inducing release of proinflammatory cytokines and upregulating expression of molecules involved in antigen presentation, sCD21 modulates critical monocyte functions that may be relevant to allergic and inflammatory disorders.
  • Cellular localization

    Type 1 membrane protein
  • Alternative names

    • C3DR
    • Complement C3d receptor
    • Complement receptor type 2
    • Cr2
    • EBV receptor
    • Epstein Barr virus receptor
    see all
  • Database links


Our Abpromise guarantee covers the use of ab45909 in the following tested applications.

The application notes include recommended starting dilutions; optimal dilutions/concentrations should be determined by the end user.

Application Abreviews Notes
Sandwich ELISA Use at an assay dependent concentration.


  • Representative Standard Curve using ab45909.



ab45909 has not yet been referenced specifically in any publications.

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