DESCRIPTION

Programmed cell death 1 (PD-1, also known as CD279) is an immunoinhibitory receptor that belongs to the CD28/CTLA-4 subfamily of the Ig superfamily. It is a 288 amino acid (aa) type I transmembrane protein composed of one Ig superfamily domain, a stalk, a transmembrane domain, and an intracellular domain containing an immunoreceptor tyrosine-based inhibitory motif (ITIM) as well as an immunoreceptor tyrosine-based switch motif (ITSM). PD-1 can be expressed on activated T cells, B cells, natural killer T cells, monocytes, and dendritic cells (DCs). Engagement of PD-1 by its ligands PD-L1 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. Blockade of PD-1 can overcome immune resistance and also has been shown to have antitumor activity.

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	948.7	63.9	6.7
2	8	253.2	11.2	4.4
3	8	134.9	6.3	4.7

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	16	952.0	55.4	5.8
2	16	257.2	13.7	5.3
3	16	140.7	10.6	7.5

RECOVERY

The recovery of human PD-1/CD279 spiked to three different levels throughout the range of the assay in various matrices was evaluated.

Sample Type		Average% of Expected	Range (%)
Human plasma	1:4	94	88-98
Cell culture supernatant	1:2	112	110-114
	1:4	109	107-112
Urine	1:8	95	91-100
	1:16	94	88-98
Cell lysate	1:16	99	84-113
	1:32	103	101-106

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 1:2.)

		Human plasma(Sample DiluentPT 3)	Cell culturesupernatant(Sample DiluentPT 4B1)	Urine(Sample DiluentPT 3)	Cell lysate(Sample DiluentPT 3-ef)
1:2	Average% of Expected	100	100	100	100
	Range (%)	-	-	-	-
1:4	Average% of Expected	89	94	108	99
	Range (%)	84-95	83-105	101-115	98-100
1:8	Average% of Expected	89	85	113	109
	Range (%)	85-93	75-96	99-127	108-110
1:16	Average% of Expected	90	-	109	127
	Range (%)	89-91	-	108-109	122-131

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human Human PD-1/CD279 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
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• Price: USD, per kit (48T / 96T options available)