DESCRIPTION

Tumor necrosis factor-alpha (TNFA/TNFSF2) is a multifunctional cytokine that plays a key role in regulating inflammation, immune functions, host defense, and apoptosis (PMID: 16407280). TNFA signals through two distinct cell surface receptors, TNFR1 (TNFRSF1A, CD120a, p55) and TNFR2 (TNFRSF1B, CD120b, p75). TNFR1 is widely expressed, whereas TNFR2 exhibits more restricted expression, being found on CD4 and CD8 T lymphocytes, endothelial cells, microglia, oligodendrocytes, neuron subtypes, cardiac myocytes, thymocytes and human mesenchymal stem cells (PMID: 20489699; 22374304). In contrast to TNFR1, TNFR2 does not have a death domain. TNFR2 only signals for antiapoptotic reactions. However, recent evidence indicates that TNFR2 also signals to induce TRAF2 degradation (PMID: 22374304). Various defects in the TNFR2 pathway, due to polymorphisms in the TNFR2 gene, upregulated expression of TNFR2 and TNFR2 shedding, have been implicated in the pathology of several autoimmune disorders (PMID: 20489699).

PRINCIPLE OF THE ASSAY

Sandwich ELISA structure (Detection antibody labeled with biotin) A capture antibody is pre-coated onto the bottom of wells which binds to analyte of interest. A detection antibody labeled with biotin also binds to the analyte. Streptavidin-HRP binds to the biotin. TMB acts as the HRP substrate and the solution color will change from colorless to blue. A stop solution containing sulfuric acid turns solution yellow. The color intensity is proportional to the quantity of bound protein which is measurable at 450 nm with the correction wavelength set at 630 nm.

PRECISION

Intra-assay Precision (Precision within an assay) Three samples of known concentration were tested 20 times on one plate to assess intra-assay precision. Inter-assay Precision (Precision between assays) Three samples of known concentration were tested in 24 separate assays to assess inter-assay precision.

Intra-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	20	464.1	22.6	4.9
2	20	98.3	3.9	4.0
3	20	34.2	1.2	3.6

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	24	477.6	20.9	4.4
2	24	99.8	5.1	5.1
3	24	32.2	3.3	10.4

RECOVERY

The recovery of human TNFRSF1B spiked to three different levels throughout the range of the assay in human serum was evaluated.

Sample Type		Average% of Expected	Range (%)
Human serum	1:16	98	85-112
	1:32	95	85-108

LINEARITY

To assess the linearity of the assay, samples were diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay. (The human serum was initially diluted 1:2. )

		Human serum
1:2	Average% of Expected	100
	Range (%)	-
1:4	Average% of Expected	91
	Range (%)	90-92
1:8	Average% of Expected	96
	Range (%)	84-107
1:16	Average% of Expected	102
	Range (%)	80-124

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human TNFRSF1B produced at Sunlong Medical™.

Ordering & shipping

• Minimum order: 1 kit
• Lead time: varies with order quantity and specifications. Please consult your local distributor or our sales team for confirmation
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• Shipping: FedEx / DHL / UPS express; cold-chain packing available on request
• Price: USD, per kit (48T / 96T options available)