Product Name:	Human Interleukin-21 (IL-21) ELISA Kit
Product Code:	HUEB1881
Alias:	Interleukin-21, IL-21, Za11, IL21
Uniprot:	Q9HBE4
Reactivity:	Human
Range:	15.6-1000 pg/mL
Detection Method:	Sandwich
Size:	96 Assay
Storage:	Please see kit components below for exact storage details
Note:	For research use only

UniProt Protein Function:	IL21: Cytokine with immunoregulatory activity. May promote the transition between innate and adaptive immunity. Induces the production of IgG(1) and IgG(3) in B-cells. May play a role in proliferation and maturation of natural killer (NK) cells in synergy with IL15. May regulate proliferation of mature B- and T-cells in response to activating stimuli. In synergy with IL15 and IL18 stimulates interferon gamma production in T-cells and NK cells. During T-cell mediated immune response may inhibit dendritic cells (DC) activation and maturation. Belongs to the IL-15/IL-21 family. 2 isoforms of the human protein are produced by alternative splicing.
UniProt Protein Details:	Protein type:Cytokine; Apoptosis; Secreted, signal peptide; Secreted; Cell development/differentiation Chromosomal Location of Human Ortholog: 4q26-q27 Molecular Function:hematopoietin/interferon-class (D200-domain) cytokine receptor binding; interleukin-2 receptor binding Biological Process: cell maturation; positive regulation of B cell proliferation; positive regulation of cell proliferation; positive regulation of cytokine production; positive regulation of inflammatory response; positive regulation of interleukin-17 production; positive regulation of natural killer cell mediated cytotoxicity; positive regulation of T cell proliferation; positive regulation of tissue remodeling; positive regulation of tyrosine phosphorylation of Stat1 protein; positive regulation of tyrosine phosphorylation of Stat3 protein; tyrosine phosphorylation of Stat3 protein Disease: Immunodeficiency, Common Variable, 11
NCBI Summary:	This gene encodes a member of the common-gamma chain family of cytokines with immunoregulatory activity. The encoded protein plays a role in both the innate and adaptive immune responses by inducing the differentiation, proliferation and activity of multiple target cells including macrophages, natural killer cells, B cells and cytotoxic T cells. Dysregulation of this gene plays a role in multiple immune-mediated diseases including lupus, psoriasis and chronic inflammatory diseases. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Dec 2011]
UniProt Code:	Q9HBE4
NCBI GenInfo Identifier:	55976599
NCBI Gene ID:	59067
NCBI Accession:	Q9HBE4.2
UniProt Secondary Accession:	Q9HBE4,A5J0L4,
UniProt Related Accession:	Q9HBE4
Molecular Weight:	16,867 Da
NCBI Full Name:	Interleukin-21
NCBI Synonym Full Names:	interleukin 21
NCBI Official Symbol:	IL21
NCBI Official Synonym Symbols:	Za11; IL-21; CVID11
NCBI Protein Information:	interleukin-21
UniProt Protein Name:	Interleukin-21
UniProt Synonym Protein Names:	Za11
Protein Family:	Interleukin
UniProt Gene Name:	IL21
UniProt Entry Name:	IL21_HUMAN

Component	Quantity (96 Assays)	Storage
ELISA Microplate (Dismountable)	8×12 strips	-20°C
Lyophilized Standard	2	-20°C
Sample Diluent	20ml	-20°C
Assay Diluent A	10mL	-20°C
Assay Diluent B	10mL	-20°C
Detection Reagent A	120µL	-20°C
Detection Reagent B	120µL	-20°C
Wash Buffer	30mL	4°C
Substrate	10mL	4°C
Stop Solution	10mL	4°C
Plate Sealer	5	-

Other materials and equipment required:

Microplate reader with 450 nm wavelength filter
Multichannel Pipette, Pipette, microcentrifuge tubes and disposable pipette tips
Incubator
Deionized or distilled water
Absorbent paper
Buffer resevoir

*Note: The below protocol is a sample protocol. Protocols are specific to each batch/lot. For the correct instructions please follow the protocol included in your kit.

Allow all reagents to reach room temperature (Please do not dissolve the reagents at 37°C directly). All the reagents should be mixed thoroughly by gently swirling before pipetting. Avoid foaming. Keep appropriate numbers of strips for 1 experiment and remove extra strips from microtiter plate. Removed strips should be resealed and stored at -20°C until the kits expiry date. Prepare all reagents, working standards and samples as directed in the previous sections. Please predict the concentration before assaying. If values for these are not within the range of the standard curve, users must determine the optimal sample dilutions for their experiments. We recommend running all samples in duplicate.

Step
1.	Add Sample: Add 100µL of Standard, Blank, or Sample per well. The blank well is added with Sample diluent. Solutions are added to the bottom of micro ELISA plate well, avoid inside wall touching and foaming as possible. Mix it gently. Cover the plate with sealer we provided. Incubate for 120 minutes at 37°C.
2.	Remove the liquid from each well, don't wash. Add 100µL of Detection Reagent A working solution to each well. Cover with the Plate sealer. Gently tap the plate to ensure thorough mixing. Incubate for 1 hour at 37°C. Note: if Detection Reagent A appears cloudy warm to room temperature until solution is uniform.
3.	Aspirate each well and wash, repeating the process three times. Wash by filling each well with Wash Buffer (approximately 400µL) (a squirt bottle, multi-channel pipette,manifold dispenser or automated washer are needed). Complete removal of liquid at each step is essential. After the last wash, completely remove remaining Wash Buffer by aspirating or decanting. Invert the plate and pat it against thick clean absorbent paper.
4.	Add 100µL of Detection Reagent B working solution to each well. Cover with the Plate sealer. Incubate for 60 minutes at 37°C.
5.	Repeat the wash process for five times as conducted in step 3.
6.	Add 90µL of Substrate Solution to each well. Cover with a new Plate sealer and incubate for 10-20 minutes at 37°C. Protect the plate from light. The reaction time can be shortened or extended according to the actual color change, but this should not exceed more than 30 minutes. When apparent gradient appears in standard wells, user should terminatethe reaction.
7.	Add 50µL of Stop Solution to each well. If color change does not appear uniform, gently tap the plate to ensure thorough mixing.
8.	Determine the optical density (OD value) of each well at once, using a micro-plate reader set to 450 nm. User should open the micro-plate reader in advance, preheat the instrument, and set the testing parameters.
9.	After experiment, store all reagents according to the specified storage temperature respectively until their expiry.

When carrying out an ELISA assay it is important to prepare your samples in order to achieve the best possible results. Below we have a list of procedures for the preparation of samples for different sample types.

Sample Type	Protocol
Serum	If using serum separator tubes, allow samples to clot for 30 minutes at room temperature. Centrifuge for 10 minutes at 1,000x g. Collect the serum fraction and assay promptly or aliquot and store the samples at -80°C. Avoid multiple freeze-thaw cycles. If serum separator tubes are not being used, allow samples to clot overnight at 2-8°C. Centrifuge for 10 minutes at 1,000x g. Remove serum and assay promptly or aliquot and store the samples at -80°C. Avoid multiple freeze-thaw cycles.
Plasma	Collect plasma using EDTA or heparin as an anticoagulant. Centrifuge samples at 4°C for 15 mins at 1000 × g within 30 mins of collection. Collect the plasma fraction and assay promptly or aliquot and store the samples at -80°C. Avoid multiple freeze-thaw cycles. Note: Over haemolysed samples are not suitable for use with this kit.
Urine & Cerebrospinal Fluid	Collect the urine (mid-stream) in a sterile container, centrifuge for 20 mins at 2000-3000 rpm. Remove supernatant and assay immediately. If any precipitation is detected, repeat the centrifugation step. A similar protocol can be used for cerebrospinal fluid.
Cell culture supernatant	Collect the cell culture media by pipette, followed by centrifugation at 4°C for 20 mins at 1500 rpm. Collect the clear supernatant and assay immediately.
Cell lysates	Solubilize cells in lysis buffer and allow to sit on ice for 30 minutes. Centrifuge tubes at 14,000 x g for 5 minutes to remove insoluble material. Aliquot the supernatant into a new tube and discard the remaining whole cell extract. Quantify total protein concentration using a total protein assay. Assay immediately or aliquot and store at ≤ -20 °C.
Tissue homogenates	The preparation of tissue homogenates will vary depending upon tissue type. Rinse tissue with 1X PBS to remove excess blood & homogenize in 20ml of 1X PBS (including protease inhibitors) and store overnight at ≤ -20°C. Two freeze-thaw cycles are required to break the cell membranes. To further disrupt the cell membranes you can sonicate the samples. Centrifuge homogenates for 5 mins at 5000xg. Remove the supernatant and assay immediately or aliquot and store at -20°C or -80°C.
Tissue lysates	Rinse tissue with PBS, cut into 1-2 mm pieces, and homogenize with a tissue homogenizer in PBS. Add an equal volume of RIPA buffer containing protease inhibitors and lyse tissues at room temperature for 30 minutes with gentle agitation. Centrifuge to remove debris. Quantify total protein concentration using a total protein assay. Assay immediately or aliquot and store at ≤ -20 °C.
Breast Milk	Collect milk samples and centrifuge at 10,000 x g for 60 min at 4°C. Aliquot the supernatant and assay. For long term use, store samples at -80°C. Minimize freeze/thaw cycles.

ELISA	Antibodies
Human IL-21 ELISA Kit	Anti-IL-21 Antibody (CAB7235)
Human IL-21 CLIA Kit (HUES01280)	Human IL-21 Monoclonal Antibody (PE Conjugated) [3A3-N2](AGEL2051)
	Human IL-21 Monoclonal Antibody (APC Conjugated) [3A3-N2](AGEL2052)
	IL21 Antibody (PACO00960)
	RTN4R Antibody (PACO43167)