Purpose | This immunoassay kit allows for the in vitro quantitative determination of human Complement 1q, C1q concentrations in cell culture supernates, serum, plasma and other biological fluids. |
Sample Type | Cell Culture Supernatant, Serum, Plasma, Biological Fluids |
Analytical Method | Quantitative |
Detection Method | Colorimetric |
Specificity | This assay recognizes recombinant and natural human C1q. |
Cross-Reactivity (Details) | No significant cross-reactivity or interference was observed. |
Sensitivity |
< 3.12 ng/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,Complement C1q subcomponent subunit A,C1QA |
Components | Reagent (Quantity): Assay plate (1×20ml), Standard (2), Sample Diluent (1×20ml), Assay Diluent A (1×10ml), Assay Diluent B (1×10ml), Detection Reagent A (1×120 μl), Detection Reagent B (1×120μl), Wash Buffer(25 x concentrate) (1×30ml), Substrate (1×10ml), Stop Solution (1×10ml), Plate sealer for 96 wells (5), Instruction (1) |
Material not included | Luminometer. Pipettes and pipette tips. EP tube Deionized or distilled water. |
Alternative Name | C1QA (C1QA ELISA Kit Abstract) |
Background | C1q is a 400 KDa protein formed from 18 peptide chains in 3 subunits of 6. Each 6 peptide subunit consists of a Y-shaped pair of triple peptide helices joined at the stem and ending in a globular non-helical head.The C1 protein, showing subunits C1r, C1s, and the C1q tails.The 80 amino-acid helical component of each triple peptide contain many Gly-X-Y sequences,where X and Y are proline, isoleucine or hydroxylysine, they therefore strongly resemble collagen fibrils. C1q is part of the activation arm of complement.It is the first element in the classic complement activation pathway that starts on binding of C1q to the antigen,either directly or through an antibody-antigen complex.C1q then interacts with and activates several proteases(C1r,C1s,C2-C4) that amplify the original response and initiate opsonization,anaphylactic reactions that attract phagocytes,and that finally directly attack the cell membrane through the membrane attack complex (MAC). In addition,C1q appears to have other potential functions through cell-specific receptors. C1q is alarge molecule made up of 18 polypeptide chain s(6 of A,6 of B,and 6 of C)held together by acombination of covalent(disulfide) and noncovalent bonds.When assembled,the C1q full molecule has two distinct regions:a globular head and a longtail.Most of the antibodies raised against C1q specific to the secondary structure of the assembled chains and are nonreactive to the amino acid sequence of each chain.The tightly bound individual polypeptide chains are difficult to separate from this complex,which requires long incubations under reducing conditions and high urea concentrations.Several proteins have globular domains similar to C1q. |
Pathways | Complement System |
Sample Volume | 100 μL |
Plate | Pre-coated |
Protocol | The microtiter plate provided in this kit has been pre-coated with an antibody specific to C1q. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated polyclonal antibody preparation specific for C1q and Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. Then a 2 TMB substrate solution is added to each well. Only those wells that contain C1q, biotin-conjugated antibody and enzyme-conjugated Avidin will exhibit a change in color. The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the color change is measured spectrophotometrically at a wavelength of 450 nm ± 2 nm. The concentration of C1q in the samples is then determined by comparing the O.D. of the samples to the standard curve. |
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 30 mL of Wash Buffer Concentrate into deionized or distilled water to prepare 750 mL of Wash Buffer. Standard - Reconstitute the Standard with 1.0 mL of Sample Diluent. This reconstitution produces a stock solution of 800 ng/ml. Allow the standard to sit for a minimum of 15 minutes with gentle agitation prior to making serial dilutions (Making serial dilution in the wells directly is not permitted). The undiluted standard serves as the high standard (800 ng/ml). The Sample Diluent serves as the zero standard (0 ng/ml). ng/mL 800 400 200 100 50 25 12.5 0 Detection Reagent A and B - Dilute to the working concentration 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 × g. Remove serum and assay immediately or aliquot and store samples at -20C or -80C. Plasma - Collect plasma using EDTA or heparin as an anticoagulant. Centrifuge samples for 15 minutes at 1000 × g at 2 - 8C within 30 minutes of collection. Store samples at -20C or -80C. Avoid repeated freeze-thaw cycles. Cell culture supernates and other biological fluids - Remove particulates by centrifugation and assay immediately or aliquot and store samples at -20C or -80C. Avoid repeated freeze-thaw cycles. Note: Serum, plasma, and cell culture supernatant samples to be used within 7 days may be stored at 2-8 C, otherwise samples must stored at -20C (≤ 1 months) or -80C (≤ 2 months) to avoid loss of bioactivity and contamination. Avoid freeze-thaw cycles. When performing the assay slowly bring samples to room temperature. Sample preparation 3 Serum/plasma samples require a 200 fold dilution. |
Assay Procedure |
Allow all reagents to reach room temperature (Please do not dissolve the reagents at 37C 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 4C 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 particular experiments. 4 |
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 x-axis against the concentration on the y-axis and draw a best fit curve through the points on the graph. The data may be linearized by plotting the log of the C1q concentrations versus the log of the O.D. and the best fit line can be determined by regression analysis. It is recommended to use some related software to do this calculation, such as curve expert 13.0. 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. |