Interleukin-21 is a cytokine that has potent regulatory effects on cells of the immune system, including natural killer (NK) cells and cytotoxic T cells that can destroy virally infected or cancerous cells. This cytokine induces cell division/proliferation in its target cells. IL-21 is expressed in activated human CD4+ T cells but not in most other tissues. In addition, IL-21 expression is up-regulated in Th2 and Th17 subsets of T helper cells, as well as T follicular cells. In fact, it was shown that IL-21 can be used to identify peripheral T follicular helper cells. Furthermore, IL-21 is expressed in NK T cells regulating the function of these cells.

Human IL-21 ELISA Kit Principle

This Human IL-21 ELISA Kit is based on sandwich ELISA, the IL-21 specific monoclonal antibody was pre-coated in the microwells, the IL-21 in sample or the IL-21 standard will be captured by the coated antibody, after wash step, the unbonded IL-21 will be removed, and then another IL-21 specific monoclonal antibody is added and incubated. After then, the plate is washed again, and the substrate is added. The color of the wells is positively proportional to the IL-21 in it. After adding the stop solution, OD values are measured with ELISA reader. Unknown samples can be calculated from the standard curve.

Kit Components

This Human IL-21 ELISA kit is a readily commercial product, it has the following components, which is sufficient for 42 testing in duplicated wells. Please always check the kit instruction manual for packaging details. For plasma and serum samples, the standard solutions are ready to use. For other samples, you may need to dilute the standard according to the kit instruction manual.

• Microtiter plate, 96wells,
• Standard, will be diluted to 7 vials,
• HRP conjugate, 1 vial,
• TMB substrate, 1 vial,
• Assay buffer, 1 vial,
• Wash buffer, 1 vial,
• Sealer film or plate cover, 1p pc
• Stop solution, 1 vial,

Specificity and sensitivity

The sensitivity is 21.7-67.9 pg/mL as MDD. The specificity is over 99%.

Result determination

The sample OD value is measured by an ELISA reader, then the standard curve is plotted. We recommend 4PL regression model or another equivalent model.

Storage and expiry

2-8 degree Celsius for at least 12 months.

Caution

• This kit is for research use only.
• The standard solution in the kit is human IL-21.
• Please read the kit instruction manual carefully before testing.
• Each run will take 80min or more, please schedule your time before experiment.