Purpose | This immunoassay kit allows for the specific measurement of human CXCR3 concentrations in serum and plasma. |
Sample Type | Serum, Plasma |
Analytical Method | Quantitative |
Detection Method | Colorimetric |
Specificity | This assay recognizes recombinant and natural human CXCR3. |
Cross-Reactivity (Details) | No significant cross-reactivity or interference was observed. |
Characteristics | Homo sapiens,Human,C-X-C chemokine receptor type 3,CXC-R3,CXCR-3,CKR-L2,G protein-coupled receptor 9,Interferon-inducible protein 10 receptor,IP-10 receptor,CXCR3,GPR9,CD183 |
Components | Reagent (Quantity): Assay plate (1), Standard (2), Sample Diluent (1x20ml), Assay Diluent A (1x10ml), Assay Diluent B (1x10ml), Detection Reagent A 1 x120μl Detection Reagent B 1 x120μl Wash Buffer(25 x concentrate) (1x30ml), Substrate (1x10ml), Stop Solution (1x10ml) |
Alternative Name | CXCR3 (CXCR3 ELISA Kit Abstract) |
Background | CD183 (CXCR3) is a multi-pass type-3, 7 span 368 aa glycoprotein. It contains an extracellular domain which contains 3 potential amino-glycosylation sites, 7 putative transmembrane-spanning domains and an intracellular carboxyl-terminal regions which has 3 intracellular loop regions. The intracellular carboxyl-terminal region contains 10 Thr/Ser residues that may become phosphorylated during CD183-mediated signaling. The DRYLAIVHA-motif in the 2nd intracellular loop is the most highly conserved sequence element in chemokine receptors. CD183 is a chemokine receptor which are G-proteins coupled receptors. CD183 shares a 30% identity with CD181 (CXCR1) and CD182 (CXCR2). CD183 has a specificity for 3 chemokines, termed IP10 IFN-g -inducible 10 kDa protein, termed Mig monokine induced by IFN-r and termed I-TAC interferon-inducible T cell a-chemoattractant. Nomenclature for chemokines and chemokine receptors is reviewed in structural subfamily CXC chemokines, in which 1 aa residue separates the 1st 2 of 4 highly conserved Cys residues. Historically, CD183 is the 3rd CXC chemokine receptor discovered and, therefore, commonly designated as CXCR3. Binding of chemokines to CD183 induces cellular responses that are involved in leukocyte traffic, most notably integrin activation, cytoskeletal changes and chemotactic migration. Inhibition by Bordetella pertussis toxin suggests the heterotrimeric G protein of the Gi-subclass couple to CD183. Signal transduction has not been further analyzed but may include the same enzymes including phospholipases, protein kinase B and C, phosphatidylinositol-3-OH kinases, MAP kinases, G protein-coupled receptor kinases, and small GTPases that were identified in the signaling cascade induced by other chemokine receptors. As a consequence of chemokine-induced cellular desensitization and phosphorylation-dependent receptor internalization, cellular responses are typically rapid and short in duration. Cellular responsiveness is restored after dephosphorylation of intracellular receptors and subsequent recycling to the cell surface. |
Sample Volume | 100 μL |
Plate | Pre-coated |
Protocol | This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for CXCR3 has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any CXCR3 present is bound by the immobilized antibody. An 2 enzyme-linked monoclonal antibody specific for CXCR3 is added to the wells. Following a wash to remove any unbound antibody-enzyme reagent, a substrate solution is added to the wells and color develops in proportion to the amount of CXCR3 bound in the initial step. The color development is stopped and the intensity of the color is measured. |
Reagent Preparation |
Bring all reagents to room temperature before use. Wash Buffer - If crystals have formed in the concentrate, warm to room temperature and mix gently until the crystals have completely dissolved. Dilute 20 mL of Wash Buffer Concentrate into 3 deionized or distilled water to prepare 500 mL of Wash Buffer. Standard - Reconstitute the Standard with 1.0 mL of Sample Diluent. This reconstitution produces a stock solution of 10 ng/mL. Allow the standard to sit for a minimum of 15 minutes with gentle agitation prior to making serial dilutions. The undiluted standard serves as the high standard (100 ng /mL). The Sample Diluent serves as the zero standard (0 ng /mL). Detection Reagent A and B - Dilute to the working concentration specified on the vial label using Assay Diluent A and B (1:100), respectively. |
Sample Collection | Serum - Use a serum separator tube (SST) and allow samples to clot for 30 minutes before centrifugation for 15 minutes at approximately 1000 x g. Remove serum and assay immediately or aliquot and store samples at -20 °C. Plasma - Collect plasma using EDTA or heparin as an anticoagulant. Centrifuge samples for 15 minutes at 1000 x g at 2 - 8 °C within 30 minutes of collection. Store samples at ≤ -20 °C. Avoid repeated freeze-thaw cycles. Note: Citrate plasma has not been validated for use in this assay. |
Assay Procedure |
Allow all reagents to reach room temperature. Arrange and label required number of strips. |
Calculation of Results |
Average the duplicate readings for each standard, control, and sample and subtract the average zero standard optical density. Create a standard curve by reducing the data using computer software capable of generating a four parameter logistic (4-PL) curve-fit. As an alternative, construct a standard curve by plotting the mean absorbance for each standard on the y-axis against the concentration on the x-axis and draw a best fit curve through the points on the graph. The data may be linearized by plotting the log of the CXCR3 concentrations versus the log of the O.D. and the best fit line can be determined by regression analysis. This procedure will produce an adequate but less precise fit of the data. If samples have been diluted, the concentration read from the standard curve must be multiplied by the dilution factor. |
Restrictions | For Research Use only |
Handling Advice |
1. The kit should not be used beyond the expiration date on the kit label. 2. Do not mix or substitute reagents with those from other lots or sources. 3. If samples generate values higher than the highest standard, further dilute the samples with the Assay Diluent and repeat the assay. Any variation in standard diluent, operator, pipetting technique, washing technique,incubation time or temperature, and kit age can cause variation in binding. 4. This assay is designed to eliminate interference by soluble receptors, ligands, binding proteins, and other factors present in biological samples. Until all factors have been tested in the Immunoassay, the possibility of interference cannot be excluded. |
Storage | 4 °C/-20 °C |
Storage Comment | The Standard, Detection Reagent A, Detection Reagent B and the 96-well strip plate should be stored at -20 °C upon being received. The other reagents can be stored at 4 °C. |