DESCRIPTION

CD13 is a type II transmembrane glycoprotein that is involved in the processing of various peptides, including peptide hormones, such as angiotensin III and IV, neuropeptides, and chemokines. CD13 may also be involved in the cleavage of peptides bound to major histocompatibility complex class II molecules of antigen-presenting cells. It could be a potential therapeutic target for inflammatory disorders. Additionally, soluble CD13 (sCD13) can bind to a G-protein-coupled receptor on activated T cells, monocytes, endothelial cells, and fibroblasts, acting as a chemoattractant for monocyte and T cell migration.

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 (ng/mL)	SD	CV%
1	8	12.26	0.60	4.89
2	8	3.01	0.09	3.09
3	8	1.60	0.05	2.84

Inter-assay Precision

Sample	n	Mean (ng/mL)	SD	CV%
1	16	12.14	1.09	9.01
2	16	2.96	0.11	3.67
3	16	1.60	0.06	3.55

RECOVERY

The recovery of mouse CD13 spiked to three different levels throughout the range of the assay in tissue lysate was evaluated.

Sample Type		Average% of Expected	Range (%)
Tissue lysate	1:160	91	86-99

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 tissue lysate was initially diluted 1:10.)

		Tissue lysate
1:2	Average% of Expected	100
	Range (%)	-
1:4	Average% of Expected	94
	Range (%)	89-100
1:8	Average% of Expected	98
	Range (%)	97-98
1:16	Average% of Expected	96
	Range (%)	95-97

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human Mouse CD13 Sandwich ELISA Kit produced at Sunlong Medical™.