膜杰作
Star Staining
- Universality - Suitable for detection of natural or structurally conserved recombinant forms of Protein A and alkaline-resistant Protein A variants, such as MabSelect SuRe™ and other ligands
- Fast time to results - less than 2 hours
- Accuracy - Tracebility of Protein A standards against BSA China National Standard (NIFDC code: 140619) with validated pharmacopoeia quantitation methodology
- Extensive validation: Validation Report (ICH compliant) available on request
- High sensitivity - Sensitivity < 20 pg/mL of recombinant Protein A and MabSelect™ SuRe Protein A or other Protein A ligands
- High IgG tolerance - Accurately quantify protein A in up to 10 mg/mL antibody
- Excellent buffer compatibility
产品展示（Product Show）
产品描述（Product Details）
| Assay Type | Sandwich-ELISA |
| Analyte | Protein A |
| Format | 96T |
| Regulatory Status | RUO |
| Sensitivity | < 20pg/mL |
| Standard Curve Range | 25 pg/mL-1600 pg/mL |
| Assay Time | 2 hr |
| Suitable Sample Type | For the quantitative determination of recombinant Protein A, alkaline-resistant Protein A and MaXtar® ARPA ligand Protein A. |
| Sample volume | 50 μL |
组分（Materials Provided）
| ID | Components | Size |
| RES024-C01 | Pre-Coated Anti-Protein A Antibody Microplate | 1 plate |
| RES024-C02A | Alkali-Tolerant Recombinant Protein A Standard (1μg/mL) | 100 μL |
| RES024-C02B | MaXtar® ARPA ligand Protein A Standard (Bio-Link Co.) (1μg/mL) | 100 μL |
| RES024-C03 | Recombinant Protein A Standard (1μg/mL) | 100 μL |
| RES024-C04 | Biotin-Anti-Protein A Antibody | 700 μL |
| RES024-C05 | Streptavidin-HRP | 300 μL |
| RES024-C06 | Dilution Buffer | 100 mL |
| RES024-C07 | 20×Washing Buffer | 30 mL |
| RES024-C08 | Substrate Solution | 12 mL |
| RES024-C09 | Stop Solution | 6 mL |
背景（Background）
Protein A is a cell wall protein of Staphylococcus aureus, it has a variety of specific biological characteristics. Due to its high affinity with the Fc part of certain immunoglobulins (especially IgG), it is widely used in the purification of biopharmaceuticals (such as antibodies, vaccines, etc.). However, during the purification, protein A may leach from the purification column and result in contamination of the antibody drugs prepared. Once the remaining protein A enters the human body, it will easily activate the immune response of the organism, and there is a safety risk, so there are strict regulations on the residual level of Protein A in antibody drug preparations. Therefore, the detection of residual Protein A in antibody drugs purified from Protein A purification column is a key quality control step in the production process of antibody drug preparations.
The Universal Protein A ELISA Kit can detect protein A or unnatural protein A variants within 2 hours, it is high sensitive and easy to use. Whether in upstream small-scale trials or downstream large-scale of antibody production processes, this kit can help you to accurate analysis of samples, monitor the protein A levels and ensure product quality.
应用说明（Application）
The kit is developed for the detection of natural or structurally conserved recombinant forms of Protein A and alkaline-resistant Protein A variants, such as MabSelect SuRe™ , MaXtar® ARPA ligand (Bio-Link Co.), etc. in bioprocess manufacturing applications. It is used as a universal protein A and variants ligand detection tool to aid in optimal antibody purification process development and in routine quality control of in-process streams as well as final product.
It is for research use only.
存储（Storage）
Unopened kit should be stored at 2°C-8°C upon receiving.
Find the expiration date on the outside packaging and do not use reagents past their expiration date.
The opened kit should be stored per components table. The shelf life is 30 days from the date of opening.
原理（Assay Principles）
The Protein A ELISA kit is used to measure the levels of protein A by employing a standard sandwich-ELISA format. The micro-plate in the kit has been pre-coated with a chicken anti-protein A polyclonal antibody.
Firstly, the standard samples provided in kit and your samples are heated in a dry heating block or boiling water bath to denature and precipitate the product antibodies, after a centrifugation step to pellet the denatured product antibody, add the standard samples and your samples supernatant to the plate, then add the Biotin-Anti-Protein A Antibody to the plate and form Antibody-antigen (Protein A) - biotinylated antibody complex, incubate and wash the wells.
Next add Horseradish peroxidase conjugated streptavidin (Streptavidin-HRP) to the plate, incubate and wash the wells to remove any unbound reactants.
At last, load the tetramethylbenzidine (TMB) substrate into the wells and monitor a blue color. The reaction is stopped by the addition of a stop solution and the color turns yellow. The intensity of the absorbance can be measured at 450nm and 630nm on a microtiter plate reader. The OD Value reflects the amount of protein A.
典型数据-Typical Data Please refer to Ds document for the assay protocol.
Detection of Recombinant Protein A by sandwich-ELISA Assay.
Immobilized Anti-Protein A Antibody can bind Recombinant Protein A. Detection was performed using Biotin-Anti-Protein A Antibody with sensitivity of 25 pg/mL (QC tested). For each experiment, a standard curve needs to be set for each micro-plate, and the specific OD value may vary depending on different laboratories, testers, or equipments. The following example data is for reference only.
Detection of Alkali-Tolerant Recombinant Protein A by sandwich-ELISA Assay.
Immobilized Anti-Protein A Antibody can bind Alkali-Tolerant Recombinant Protein A. Detection was performed using Biotin-Anti-Protein A Antibody with sensitivity of 25 pg/mL (QC tested). For each experiment, a standard curve needs to be set for each micro-plate, and the specific OD value may vary depending on different laboratories, testers, or equipments. The following example data is for reference only.
Detection of MaXtar® ARPA ligand Protein A (Bio-Link Co.) by sandwich-ELISA Assay.
Immobilized Anti-Protein A Antibody can bind MaXtar® ARPA ligand Protein A (Bio-Link Co.). Detection was performed using Biotin-Anti-Protein A Antibody with sensitivity of 25 pg/mL (QC tested). For each experiment, a standard curve needs to be set for each micro-plate, and the specific OD value may vary depending on different laboratories, testers, or equipments. The following example data is for reference only.
验证（Validation）
批内差异（Intra-Assay Statistics）
Three samples of known concentration were tested ten times on one plate to assess intra-assay precision, Intra-Assay Precision CV＜10%.
批间差异（Inter-Assay Statistics）
Three samples of known concentration were tested in ten separate assays to assess inter-assay precision, Inter-Assay Precision CV<20%.
回收率（Recovery）
The following recovery tests were conducted by adding different concentrations of Protein A to Human IgG1（Bevacizumab）, and the final concentration of Human IgG1（Bevacizumab）is 10mg/mL to calculate the recovery rate. For Recombinant Protein A, Alkali-Tolerant Recombinant Protein A and MaXtar® ARPA ligand Protein A (Bio-Link Co.), the recovery ranges are 98-118%, 86-109% and 79-106%, respectively.
The following recovery tests were conducted by adding different concentrations of Protein A to Human IgG4（Toripalimab）, and the final concentration of Human IgG4（Toripalimab）is 10mg/mL to calculate the recovery rate. For Recombinant Protein A, Alkali-Tolerant Recombinant Protein A and MaXtar® ARPA ligand Protein A (Bio-Link Co.), the recovery ranges are 97-106%, 93-104% and 86-105%, respectively.
干扰效应(Interference effect)
We have conducted interference effect test about frequently-used buffers, they have excellent buffer compatibility. For specific buffers, it is recommended that you verify recovery to determine the minimum dilution ratio.
专属性（Specificity）
Host cell protein (HCP) and host cell DNA (HCD) were added to human IgG1 (Bevacizumab) and human IgG4 (Toripalimab), respectively, which were higher than the usual quality standard limit. Then three samples of known concentration of Protein A were added, respectively, and the ratio of Protein A recovery in the Protein A added samples without HCP and HCD was added as the specificity verification index. The calculation formula was as follows: (S3-S1) / (S2-S1) × 100%, the experimental design is as follows.
The specificity results are as follows.
