DESCRIPTION

Vascular endothelial growth factor receptor-1 (VEGFR-1, FLT-1) is a receptor tyrosine kinase belonging to the VEGFR family. VEGF is a key regulator of physiological angiogenesis and has also been implicated in pathological angiogenesis associated with tumors, intraocular neovascular disorders and other conditions. The biological effects of VEGF are mediated by VEGFR-1 and VEGFR-2. Both the two receptors have seven immunoglobulin-like repeats in the extracellular domain, a single transmembrane region and a tyrosine kinase domain. VEGFR-1 binds VEGFA, PIGF and VEGFB, and plays an essential role in the development of embryonic vasculature, the regulation of angiogenesis, cell survival, cell migration, macrophage function, chemotaxis, and cancer cell invasion. Soluble VEGF receptor-1 (sVEGFR-1, sFlt-1), a truncated version of the cell membrane-spanning VEGFR-1, has the potential to act as a decoy receptor for VEGFA. Elevated serum sVEGFR-1 have been found in women with preeclampsia. Excess placental sVEGFR-1 may contribute to endothelial dysfunction, hypertension, and proteinuria in preeclampsia.

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	541.8	21.2	3.9
2	20	1,260.9	75.0	5.9
3	20	2,346.7	117.9	5.0

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	24	558.4	22.8	4.1
2	24	1,147.1	56.9	5.0
3	24	2,271.2	59.9	2.6

RECOVERY

The recovery of human VEGFR-1 spiked to three different levels throughout the range of the assay in various matrices was evaluated. (The plasma sample was initially diluted 1:4 )

Sample Type		Average% of Expected	Range (%)
Human plasma	1:2	98	80-116
	1:4	97	90-110
Cell culture supernatant	1:2	106	103-113
	1:4	96	87-102

LINEARITY

To assess the linearity of the assay, human plasma samples were diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay. Cell culture supernatant was spiked with high concentrations of human VEGFR-1 and diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay.(The plasma samples were initially diluted 1:2)

		Human plasma (Sample Diluent PT1)	Cell culture supernatant (SampleDiluent PT 1)
1:2	Average% of Expected	90	87
	Range (%)	72-107	83-92
1:4	Average% of Expected	106	88
	Range (%)	100-112	86-92
1:8	Average% of Expected	100	92
	Range (%)	99-101	89-94
1:16	Average% of Expected	79	94
	Range (%)	76-81	93-95

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human VEGFR-1 produced at Sunlong Medical™.

Ordering & shipping

• Minimum order: 1 kit
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