Human CD28 enzyme-linked immunoassay kit
| Specification | 96 Test |
|---|---|
| Sensitivity | 1.41 pg/ml (50 μl)；57.28 pg/ml (10 μl)； |
| Standard Curve Range | 156.25~10000 pg/ml |
| Standard Curve Gradient | 7 Points |
| Number of Incubations | 2 |
| Detectable sample | Liquid phase sample of soluble substances. For example: serum, plasma, cell culture supernatant, tissue grinding liquid, etc. |
| Sample Volume | 50 μl/10 μl |
| Type | Ready-to-Use |
| Operation Duration | 120min |
| pg/ml | O.D. | Average | Corrected | |
|---|---|---|---|---|
| 0.00 | 0.0102 | 0.0092 | 0.0097 | |
| 156.25 | 0.0309 | 0.0313 | 0.0311 | 0.0214 |
| 312.50 | 0.0496 | 0.0578 | 0.0537 | 0.0440 |
| 625.00 | 0.0966 | 0.1092 | 0.1029 | 0.0932 |
| 1250.00 | 0.2040 | 0.2336 | 0.2188 | 0.2091 |
| 2500.00 | 0.5139 | 0.5597 | 0.5368 | 0.5271 |
| 5000.00 | 1.3250 | 1.5090 | 1.4170 | 1.4073 |
| 10000.00 | 3.3340 | 3.5900 | 3.4620 | 3.4523 |
Precision
| Intra-assay Precision | Inter-assay Precision | |||||
| Sample Number | S1 | S2 | S3 | S1 | S2 | S3 |
| 22 | 22 | 22 | 6 | 6 | 6 | |
| Average(pg/ml) | 203.4 | 1052.0 | 3276.1 | 166.4 | 957.1 | 3088.7 |
| Standard Deviation | 11.5 | 37.4 | 176.2 | 3.5 | 29.7 | 91.4 |
| Coefficient of Variation(%) | 5.6 | 3.6 | 5.4 | 2.1 | 3.1 | 3.0 |
Intra-assay Precision (Precision within an assay) Three samples of known concentration were tested twenty times on one plate to assess intra-assay precision.
Inter-assay Precision (Precision between assays) Three samples of known concentration were tested six times on one plate to assess intra-assay precision.
Spike Recovery
The spike recovery was evaluated by spiking 3 levels of human CD28 into health human serum sample. The un-spiked serum was used as blank in this experiment.
The recovery ranged from 85% to 113% with an overall mean recovery of 103%.
Sample Values
| Sample Matrix | Sample Evaluated | Range (pg/ml) | Detectable (%) | Mean of Detectable (pg/ml) |
|---|---|---|---|---|
| Serum | 30 | 3.32-816.93 | 100 | 104.41 |
Serum/Plasma – Thirty samples from apparently healthy volunteers were evaluated for the presence of CD28 in this assay. No medical histories were available for the donors.
Product Data Sheet
Background: CD28
CD28 and CTLA-4, together with their ligands, B7-1 and B7-2, constitute one of the dominant costimulatory pathways that regulate T and B cell responses. CD28 and CTLA-4 are structurally homologous molecules that are members of the immunoglobulin (Ig) gene superfamily. Both CD28 and CTLA-4 are composed of a single Ig
V‑like extracellular domain, a transmembrane domain and an intracellular domain. CD28 and CTLA-4 are both expressed on the cell surface as disulfide-linked homodimers or as monomers. The genes encoding these two molecules are closely linked on human chromosome 2 and mouse chromosome 1. Mouse CD28 is expressed constitutively on virtually 100% of mouse T cells and on developing thymocytes. Cell surface expression of mouse CD28 is down-regulated upon ligation of CD28 in the presence of PMA or PHA. In contrast, CTLA-4 is not expressed constitutively but is up-regulated rapidly following T cell activation and CD28 ligation. Cell surface expression of mouse CTLA-4 peaks approximately 48 hours after activation. Although both CTLA-4 and CD28 can bind to the same ligands, CTLA-4 binds to B7-1 and B7-2 with a 20-100 fold higher affinity than CD28. CD28/B7 interaction has been shown to prevent apoptosis of activated T cells via the upregulation of Bcl-xL. CD28 ligation has also been shown to regulate Th1/Th2 differentiation.
