DESCRIPTION

CXCL1 a is a member of CXC family and also known as keratinocyte-derived chemokines (KC) or growth-related oncogene (GRO). CXCL1 is expressed by macrophages, neutrophils and epithelial cells. CXCL1 binding specifically to the CXC chemokine receptor CXCR2, is involved in fibrogenesis and angiogenesis. This protein also plays a role in inflammation and as a chemoattractant for neutrophils. CXCL1 is upregulated in some types of human cancer, including colorectal, bladder, breast, prostate and skin cancers.

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	2,005.0	79.1	3.9
2	8	488.4	15.6	3.2
3	8	266.1	9.4	3.5

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	16	1,977.8	78.7	4.0
2	16	491.4	22.8	4.6
3	16	261.7	12.5	4.8

RECOVERY

The recovery of human CXCL1 spiked to three different levels throughout the range of the assay in various matrices was evaluated.

Sample Type		Average% of Expected	Range (%)
Human plasma	1:2	83	83-84
	1:4	94	88-106
Cell culture supernatant	1:2	120	119-120

LINEARITY

To assess the linearity of the assay, human plasma samples were spiked with high concenthumanions of human CXCL1 in various matrices and diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay. Cell culture supernatant samples were diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay. (The cell culture supernatant was initially diluted 1:5.)

		Human plasma(Sample Diluent PT 3)	Cell culture supernatant(Sample Diluent PT 4B1)
1:2	Average% of Expected	76	100
	Range (%)	70-83	-
1:4	Average% of Expected	86	85
	Range (%)	77-95	80-90
1:8	Average% of Expected	95	85
	Range (%)	86-103	81-90
1:16	Average% of Expected	96	93
	Range (%)	89-102	89-96

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human CXCL1 produced at Sunlong Medical™.