< 0.5% cross-reactivity observed with available related molecules.Cross-species reactivity not tested.
Interference observed with 1 or more available related molecules.
The Quantikine Human IL-1 sRII Immunoassay is a 3.5 hour solid phase ELISA designed to measure IL-1 sRII in serum, plasma, and cell culture supernates. It contains insect cell-expressed recombinant human IL-1 sRII and has been shown to quantitate the recombinant factor accurately. Results obtained using natural IL-1 sRII showed linear curves that were parallel to the standard curves obtained using the kit standards. These results indicate that this kit can be used to determine relative mass values for natural IL-1 sRII. The presence of high levels of IL-1 beta (> 7.5 ng/mL) in samples has been found to produce some interference (> 10% change) when assaying samples containing IL-1 sRII in the mid-level range.
Intra-Assay Precision (Precision within an assay) Three samples of known concentration were tested on one plate to assess intra-assay precision.
Inter-Assay Precision (Precision between assays) Three samples of known concentration were tested in separate assays to assess inter-assay precision.
The recovery of IL-1 sRII spiked to three different levels throughout the range of the assay in various matrices was evaluated.
Average % Recovery
Cell Culture Media (n=5)
Citrate Plasma (n=5)
EDTA Plasma (n=5)
Heparin Plasma (n=5)
To assess the linearity of the assay, five samples were spiked with high concentrations of IL-1 sRII in various matrices and diluted with Calibrator Diluent to produce samples with values within the dynamic range of the assay.
Preparation and Storage
Store the unopened product at 2 - 8 °C. Do not use past expiration date.
Background: IL-1 RII
Two distinct types of receptors that bind the pleiotropic cytokines IL-1 alpha and IL-1 beta have been described. The IL-1 receptor Type I is an 80 kDa transmembrane protein that is expressed predominantly by T cells, fibroblasts, and endothelial cells. IL-1 receptor Type II is a 68 kDa transmembrane protein found on B lymphocytes, neutrophils, monocytes, large granular leukocytes and, endothelial cells. Both receptors are members of the immunoglobulin superfamily and show approximately 28% sequence similarity in their extracellular domains. The two receptor types do not heterodimerize in a receptor complex.
IL-1 RII has a short cytoplasmic domain and does not transduce IL-1 signals. In addition to the membrane-bound form of IL-1 RII, a naturally-occurring soluble form of IL-1 RII has been described. It has been suggested that the Type II receptor, either as the membrane-bound or as the soluble form, serves as a decoy for IL-1 and inhibits IL-1 action by blocking the binding of IL-1 to the signaling Type I receptor complex. Recombinant IL-1 soluble receptor type II is a potent antagonist of IL-1 action.
Interleukin 1 Receptor II
Entrez Gene IDs
7850 (Human); 16178 (Mouse);
beta; CD121b antigen; CD121b; IL-1 R beta; IL1R2; IL1RBCD121 antigen-like family member B; IL-1R-beta; IL1RII; IL-1RII; IL-1RT2; IL-1RT-2; interleukin 1 receptor, type II; Interleukin-1 receptor beta; MGC47725;
Refer to the product for complete assay procedure.
Bring all reagents and samples to room temperature before use. It is recommended that all samples, standards, and controls be assayed in duplicate.
Prepare all reagents, standard dilutions, and samples as directed in the product insert.
Remove excess microplate strips from the plate frame, return them to the foil pouch containing the desiccant pack, and reseal.
100 µL Assay Diluent
Add 100 µL of Assay Diluent to each well.
100 µL Standard, Control, or Sample
Add 100 µL of Standard, control, or sample to each well. Cover with a plate sealer, and incubate at room temperature for 2 hours.
Aspirate each well and wash, repeating the process twice for a total of 3 washes.
200 µL Conjugate
Add 200 µL of Conjugate to each well. Cover with a new plate sealer, and incubate at room temperature for 1 hour.
Aspirate and wash 3 times.
200 µL Substrate Solution
Add 200 µL Substrate Solution to each well. Incubate at room temperature for 20 minutes. PROTECT FROM LIGHT.
50 µL Stop Solution
Add 50 µL of Stop Solution to each well. Read at 450 nm within 30 minutes. Set wavelength correction to 540 nm or 570 nm.
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