Human IL-21 DuoSet ELISA

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Human IL-21 DuoSet ELISA Summary

Assay Type
Solid Phase Sandwich ELISA
96-well strip plate
Assay Range
15.6 - 1,000 pg/mL
Please see the product datasheet

* Provided that the recommended microplates, buffers, diluents, substrates and solutions are used, and the assay is run as summarized in the Assay Procedure provided.

This DuoSet ELISA Development kit contains the basic components required for the development of sandwich ELISAs to measure natural and recombinant human Interleukin 21 (IL-21). The suggested diluent is suitable for the analysis of most cell culture supernate, serum, and plasma samples. Diluents for complex matrices, such as serum and plasma, should be evaluated prior to use in this DuoSet.

Product Features

  • Optimized capture and detection antibody pairings with recommended concentrations save lengthy development time
  • Development protocols are provided to guide further assay optimization
  • Assay can be customized to your specific needs
  • Economical alternative to complete kits

Kit Content

  • Capture Antibody
  • Detection Antibody
  • Recombinant Standard
  • Streptavidin conjugated to horseradish-peroxidase (Streptavidin-HRP)

Other Reagents Required

DuoSet Ancillary Reagent Kit 2 (5 plates): (Catalog # DY008) containing 96 well microplates, plate sealers, substrate solution, stop solution, plate coating buffer (PBS), wash buffer, and Reagent Diluent Concentrate 2.

The components listed above may be purchased separately:
PBS: (Catalog # DY006), or 137 mM NaCl, 2.7 mM KCl, 8.1 mM Na2HPO4, 1.5 mM KH2PO4, pH 7.2 - 7.4, 0.2 µm filtered

Wash Buffer: (Catalog # WA126), or 0.05% Tween® 20 in PBS, pH 7.2-7.4

Reagent Diluent: 0.1% BSA, 0.05% Tween 20 in Tris-buffered Saline (20mM Trizma base, 150mM NaCl) pH 7.2-7.4, 0.2 µm filtered

Substrate Solution: 1:1 mixture of Color Reagent A (H2O2) and Color Reagent B (Tetramethylbenzidine) (Catalog # DY999)

Stop Solution: 2 N H2SO4 (Catalog # DY994)

Microplates: R&D Systems (Catalog # DY990)

Plate Sealers: ELISA Plate Sealers (Catalog # DY992)

Product Datasheets

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Preparation and Storage

The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage
Store the unopened product at 2 - 8 °C. Do not use past expiration date.

Background: IL-21

IL-21 (Interleukin-21) is member of the family of cytokines that utilize the common gamma chain as a receptor subunit. This subunit is also a component of the receptors for IL-2, IL-4, IL-7, IL-9, and IL-15. IL-21 is produced by activated T follicular helper cells (Tfh), Th17 cells, and NKT cells. It exerts its biological effects through a heterodimeric receptor complex of the common gamma chain and the IL-21-specific IL-21 R. IL-21 supports Tfh cell development, immunoglobulin affinity maturation, plasma cell differentiation, B cell memory responses, and the migration of dendritic cells to draining lymph nodes. It costimulates the activation, proliferation, and survival of CD8+ T cells and NKT cells and promotes Th17 cell polarization. It blocks the generation of regulatory T cells and their suppressive effects on CD4+ T cells. In addition, IL-21 suppresses cutaneous hypersensitivity reactions by limiting allergen-specific IgE production and mast cell degranulation.

Long Name:
Interleukin 21
Entrez Gene IDs:
59067 (Human); 60505 (Mouse); 365769 (Rat); 442935 (Canine); 100344172 (Rabbit)
Alternate Names:
CVID11; IL21; IL-21; IL-21Za11interleukin-21; interleukin 21; interleukin-21 isoform; Za11

Assay Procedure


Plate Preparation

  1. Dilute the Capture Antibody to the working concentration in PBS without carrier protein. Immediately coat a 96-well microplate with 100 μL per well of the diluted Capture Antibody. Seal the plate and incubate overnight at room temperature.
  2. Aspirate each well and wash with Wash Buffer, repeating the process two times for a total of three washes. Wash by filling each well with Wash Buffer (400 μL) using a squirt bottle, manifold dispenser, or autowasher. Complete removal of liquid at each step is essential for good performance. After the last wash, remove any remaining Wash Buffer by aspirating or by inverting the plate and blotting it against clean paper towels.
  3. Block plates by adding 300 μL Reagent Diluent to each well. Incubate at room temperature for a minimum of 1 hour.
  4. Repeat the aspiration/wash as in step 2. The plates are now ready for sample addition.

Assay Procedure

  1. Add 100 μL of sample or standards in Reagent Diluent, or an appropriate diluent, per well. Cover with an adhesive strip and incubate 2 hours at room temperature.
  2. Repeat the aspiration/wash as in step 2 of Plate Preparation.
  3. Add 100 μL of the Detection Antibody, diluted in Reagent Diluent, to each well. Cover with a new adhesive strip and incubate 2 hours at room temperature.
  4. Repeat the aspiration/wash as in step 2 of Plate Preparation.
  5. Add 100 μL of the working dilution of Streptavidin-HRP to each well. Cover the plate and incubate for 20 minutes at room temperature. Avoid placing the plate in direct light.
  6. Repeat the aspiration/wash as in step 2.
  7. Add 100 μL of Substrate Solution to each well. Incubate for 20 minutes at room temperature. Avoid placing the plate in direct light.
  8. Add 50 μL of Stop Solution to each well. Gently tap the plate to ensure thorough mixing.
  9. Determine the optical density of each well immediately, using a microplate reader set to 450 nm. If wavelength correction is available, set to 540 nm or 570 nm. If wavelength correction is not available, subtract readings at 540 nm or 570 nm from the readings at 450 nm. This subtraction will correct for optical imperfections in the plate. Readings made directly at 450 nm without correction may be higher and less accurate.

Citations for Human IL-21 DuoSet ELISA

R&D Systems personnel manually curate a database that contains references using R&D Systems products. The data collected includes not only links to publications in PubMed, but also provides information about sample types, species, and experimental conditions.

8 Citations: Showing 1 - 8
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  1. Interleukin-21 modulates balance between regulatory T cells and T-helper 17 cells in chronic hepatitis B virus infection
    Authors: Cai, Y;Ji, H;Zhou, X;Zhao, K;Zhang, X;Pan, L;Shi, R;
    BMC infectious diseases
    Species: Human
    Sample Types: Serum
  2. PD-1highCXCR5-CD4+ peripheral helper T�cells promote CXCR3+ plasmablasts in human acute viral infection
    Authors: H Asashima, S Mohanty, M Comi, WE Ruff, KB Hoehn, P Wong, J Klein, C Lucas, I Cohen, S Coffey, N Lele, L Greta, K Raddassi, O Chaudhary, A Unterman, B Emu, SH Kleinstein, RR Montgomery, A Iwasaki, CS Dela Cruz, N Kaminski, AC Shaw, DA Hafler, TS Sumida
    Cell Reports, 2023-01-02;0(0):111895.
    Species: Human
    Sample Types: Cell Culture Supernates
  3. Functional and structural characteristics of HLA-B*13:01-mediated specific T cells reaction in dapsone-induced drug hypersensitivity
    Authors: H Jiang, CW Wang, Z Wang, Y Dai, Y Zhu, YS Lee, Y Cao, WH Chung, S Ouyang, H Wang
    Journal of Biomedical Science, 2022-08-13;29(1):58.
    Species: Human
    Sample Types: Cell Culture Supernates
  4. Transient and durable T cell reactivity after COVID-19
    Authors: A Martner, H Grauers Wi, A Törnell, J Ringlander, M Arabpour, M Lindh, M Lagging, S Nilsson, K Hellstrand
    Oncogene, 2022-07-12;119(30):e2203659119.
    Species: Human
    Sample Types: Plasma
  5. Characterization of memory T cell subsets and common gamma-chain cytokines in convalescent COVID-19 individuals
    Authors: A Rajamanick, N Pavan Kuma, AN Pandiaraj, N Selvaraj, S Munisankar, RM Renji, V Venkataram, M Murhekar, JWV Thangaraj, SK Muthusamy, GK Chethrapil, T Bhatnagar, M Ponnaiah, S Ramasamy, S Velusamy, S Babu
    Journal of leukocyte biology, 2022-03-08;0(0):.
    Species: Human
    Sample Types: Plasma
  6. Circulating Cytokines in Metastatic Breast Cancer Patients Select Different Prognostic Groups and Patients Who Might Benefit from Treatment beyond Progression
    Authors: M Paccagnell, A Abbona, A Michelotti, E Geuna, F Ruatta, E Landucci, N Denaro, P Vanella, C Lo Nigro, D Galizia, M Merlano, O Garrone
    Vaccines, 2022-01-05;10(1):.
    Species: Human
    Sample Types: Plasma
  7. Plasma interleukin-21 levels and genetic variants are associated with susceptibility to rheumatoid arthritis
    Authors: Y Hao, L Xie, J Xia, Z Liu, B Yang, M Zhang
    Bmc Musculoskeletal Disorders, 2021-03-05;22(1):246.
    Species: Human
    Sample Types: Plasma
  8. Defects of CTLA-4 Are Associated with Regulatory T Cells in Myasthenia Gravis Implicated by Intravenous Immunoglobulin Therapy
    Authors: W Xu, M Ren, S Ghosh, K Qian, Z Luo, A Zhang, C Zhang, J Cui
    Mediators Inflamm., 2020-02-14;2020(0):3645157.
    Species: Human
    Sample Types: Serum


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