DESCRIPTION

Signal regulatory protein Alpha (SIRP Alpha), also known as CD172a, was first identified as a membrane protein present mainly on macrophages and myeloid cells. SIRP Alpha recognizes as ligand CD47, a receptor expressed on all normal cells, but often overexpressed on cancer cells. The interaction plays a role in controlling phagocytosis, and CD47 is often termed a "don't-eatme" signal through its effect on SIRP Alpha.

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	2,220.1	66.5	3.0
2	8	506.0	10.3	2.0
3	8	268.2	2.1	0.8

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	16	2,257.6	104.7	4.6
2	16	502.8	10.5	2.1
3	16	271.0	3.8	1.4

RECOVERY

The recovery of human SIRP Alpha/CD172a spiked to three different levels throughout the range of the assay in various matrices was evaluated.

Sample Type		Average% of Expected	Range (%)
Human serum	1:80	88	87-90
	1:160	94	89-97
Cell lysate	1:16	103	94-114

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 1:10. The cell lysate was initially diluted 1:2.)

		Human serum	Cell lysate
1:2	Average% of Expected	100	100
	Range (%)	-	-
1:4	Average% of Expected	101	87
	Range (%)	96-105	85-88
1:8	Average% of Expected	99	79
	Range (%)	89-109	79-80
1:16	Average% of Expected	89	78
	Range (%)	81-97	74-82

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human Human SIRP Alpha/CD172a Sandwich ELISA Kit produced at Sunlong Medical™.

Ordering & shipping

• Minimum order: 1 kit
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