DESCRIPTION

PD-L1 (programmed cell death ligand 1, also known as CD274 or B7-H1) is a 290 aa type I transmembrane protein. PD-L1 is expressed constitutively on T cells, B cells, DCs, macrophages, mesenchymal stem cells and cultured bone marrow-derived mast cells. In addition, PD-L1 is also expressed on many nonhematopoietic cell types, including vascular endothelial cells, epithelial cells, muscle cells, hepatocytes, pancreatic islet cells, astrocytes in the brain, placental syncytiotrophoblasts, and cells in cornea, iris-ciliary body and retina of eye. PD-L1 is frequently upregulated in a wide variety of solid tumors, including melanoma, ovarian, lung, glioblastoma, breast, and pancreatic cancers. PD-L1 and PD-L2 are two ligands of PD-1. Engagement of PD-1 by PDL1 or PD-L2 transduces a signal that inhibits T-cell proliferation, cytokine production, and cytolytic function. It is critical for the regulation of T cell function during tolerance, autoimmunity and infection. Besides the membrane-bound form, PD-L1 can also exist as a soluble form (sPD-L1) generated either by proteolytic cleavage of membrane-bound form or by translation of alternative spliced mRNA.

PRINCIPLE OF THE ASSAY

Sandwich ELISA structure (Detection antibody labeled with HRP) A capture antibody is pre-coated onto the bottom of wells which binds to analyte of interest. A detection antibody labeled with HRP also binds to the analyte. 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 8 times on one plate to assess intra-assay precision. Inter-assay Precision (Precision between assays) Three samples of known concentration were tested in 16 separate assays to assess inter-assay precision.

Intra-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	8	274.5	7.6	2.8
2	8	68.0	0.9	1.3
3	8	20.9	0.6	3.1

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	16	274.7	7.7	2.8
2	16	68.1	1.0	1.5
3	16	21.5	0.9	4.1

RECOVERY

The recovery of human PD-L1/CD274 spiked to three different levels throughout the range of the assay in various matrices was evaluated.

Sample Type		Average% of Expected	Range (%)
Human serum	1:8	81	76-86
	1:16	92	88-95
Cell culture supernatant	1:8	93	89-96
	1:16	95	91-98
Urine	1:2	94	92-97
	1:4	98	95-104
Cell lysate	1:1,600	105	98-116

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 cell lysate was initially diluted 1:100.)

		Human serum	Cell culturesupernatant	Urine	Cell lysate
1:2	Average% of Expected	100	100	100	100
	Range (%)	-	-	-	-
1:4	Average% of Expected	110	105	97	99
	Range (%)	106-115	103-107	96-98	96-101
1:8	Average% of Expected	114	112	87	99
	Range (%)	106-122	106-119	85-89	97-101
1:16	Average% of Expected	117	115	88	101
	Range (%)	114-120	107-124	76-99	97-104

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human Human PD-L1/CD274 Sandwich ELISA Kit 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
• Payment: T/T 100% in advance; PayPal; Alibaba Trade Assurance
• Shipping: FedEx / DHL / UPS express; cold-chain packing available on request
• Price: USD, per kit (48T / 96T options available)