Rat IL-21 ELISA Kit

Interleukin-21 (IL-21) is a cytokine that plays a vital role in immune responses, including the regulation of T and B cell function, promotion of immune cell proliferation, and modulation of antibody production. From Assay Genie, this Sandwich ELISA kit is designed for the quantitative detection of IL-21 in rat samples, with reactivity validated for serum, plasma, cell culture supernatant, cell or tissue lysate, and other liquid samples. The assay uses a colorimetric, double-antibody sandwich format.

The kit delivers a sensitivity of 9.375 pg/mL across a standard curve range of 15.625–1000 pg/mL, with reagents stored at 2-8°C for 12 months. Recovery testing yielded average values of 98% for serum (range 92–105%, n=5), 97% for EDTA plasma (range 87–104%, n=5), and 97% for heparin plasma (range 90–104%, n=5). Linearity was demonstrated at dilutions of 1:2, 1:4, and 1:8, with serum samples ranging 82–103%, EDTA plasma 81–100%, and heparin plasma 83–100%.

The standard protocol follows six steps: equilibrate reagents and load standards, samples, and controls onto the pre-coated plate; incubate at 37°C for 90 minutes for antigen binding; add biotin-labeled detection antibody and incubate for 60 minutes; add HRP-Streptavidin and incubate for 30 minutes; develop with TMB substrate in the dark for 10–20 minutes; then add stop solution and read absorbance at 450 nm. Sample preparation includes clotting and centrifugation at 1000 × g for 20 minutes for serum, anticoagulant collection with centrifugation at 1000 × g for 15 minutes at 2–8°C for plasma, homogenization in PBS with protease inhibitors for tissue, and clarification by centrifugation at 2500 rpm for 5 minutes for cell culture supernatant.