Purpose | This immunoassay kit allows for the specific measurement of human Thrombopoietin, TPO concentrations in cell culture supernates, serum and plasma. |
Sample Type | Cell Culture Supernatant, Serum, Plasma |
Analytical Method | Quantitative |
Detection Method | Colorimetric |
Specificity | This assay recognizes recombinant and natural human TPO. |
Cross-Reactivity (Details) | No significant cross-reactivity or interference was observed. |
Sensitivity |
< 3.9 pg/mL The sensitivity of this assay, or Lower Limit of Detection (LLD) was defined as the lowest detectable concentration that could be differentiated from zero. |
Characteristics | Homo sapiens,Human,Thrombopoietin,C-mpl ligand,ML,Megakaryocyte colony-stimulating factor,Megakaryocyte growth and development factor,MGDF,Myeloproliferative leukemia virus oncogene ligand, |
Components | Reagent (Quantity): Assay plate (1), Standard (2), Sample Diluent (1x20ml), Assay Diluent A (1x10ml), Assay Diluent B (1x10ml), Detection Reagent A (1x120μl), Detection Reagent B (1x120μl), Wash Buffer(25 x concentrate) (1x30ml), Substrate (1x10ml), Stop Solution (1x10ml) |
Alternative Name | THPO (THPO ELISA Kit Abstract) |
Background | Thrombopoietin (Tpo), also known as megakaryocyte growth and development factor (MGDF), the ligand for the receptor encoded by the c-Mplproto-oncogene, is a key regulator of megakaryocytopoiesis and thrombopoiesis in vitroand in vivo. Tpo has been purified and cloned from several species including mouse, mouse, rat, and dog. The proteins from the various species are highly conserved, exhibiting from 69-75% sequence identity at the amino acid sequence level. The mouse Tpo cDNA sequence encodes a 356 amino acid residue protein with a 21 amino acid residue signal peptide that is cleaved to yield the 335 amino acid residue mature protein. Mature Tpo can be divided into two domains: the amino-terminal half with homology to erythropoietin (Epo) and the carboxy-terminal half rich in serine, threonine and proline residues and containing seven potential N-linked glycosylation sites. The Epo-domain of mouse Tpo shows approximately 21% amino acid sequence identity to mouse Epo and has been shown to activate the c-Mplreceptor. The carboxy terminus domain of Tpo has been shown to regulate the specific activity and circulating half-life of Tpo. The carboxy-terminal may also have a role in promoting the efficient biosynthesis and secretion of Tpo. The cDNA for a variant form of Tpo (Tpo-2) with a four amino acid residue deletion within the Epo homology domain has been isolated. Tpo-2 is very poorly secreted and lacks Tpo activity. Tpo mRNA is expressed predominantly in ***** and fetal liver, kidney and bone marrow stromal cells. |
Pathways | JAK-STAT Signaling, Hormone Activity |
Sample Volume | 100 μL |
Plate | Pre-coated |
Protocol | This assay employs the quantitative sandwich enzyme immunoassay technique. A antibody specific for TPO has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any TPO present is bound by the immobilized antibody. An enzyme-linked antibody specific for TPOis 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 TPO 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 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 2,000 pg/mL. Allow the standard to sit for a minimum of 15 minutes with gentle agitation prior to making serial dilutions. The diluted standard serves as the high 3 standard (1,000 pg/mL). The Sample Diluent serves as the zero standard (0 pg/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 | Cell culture supernates - Remove particulates by centrifugation and assay immediately or aliquot and store samples at ≤ -20 °C. Avoid repeated freeze-thaw cycles. 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 TPO 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. |