DESCRIPTION

CD62L (L-selectin) is an adhesion molecule belonging to the selectin family, primarily expressed on the surface of white blood cells, and plays a role in various physiological and pathological processes, including lymphocyte homing, inflammatory responses, and immune cell positioning. It plays a crucial role in the homing process of white blood cells, helping them migrate from the bloodstream into lymphoid tissues. During inflammatory responses, CD62L mediates the initial adhesion of white blood cells to endothelial cells, facilitating their rolling and migration. Additionally, CD62L is a marker for central memory T cells, which have higher expression levels of CD62L and can rapidly relocate to lymph nodes and other sites for a swift secondary response.

PRINCIPLE OF THE ASSAY

An anti-tag antibody is pre-coated onto the bottom of wells. After adding antigen or samples, Tagged-Capture antibody and HRP-conjugated detection antibody, a sandwich complex is formed in the solution. TMB acts as a HRP substrate, and the solution color will change from colorless to blue. A stop solution containing sulfuric acid turns the 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	1,190.6	47.2	4.0
2	8	266.4	5.8	2.2
3	8	131.3	4.1	3.1

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	16	1,231.8	64.1	5.2
2	16	272.4	9.9	3.6
3	16	129.9	4.1	3.2

RECOVERY

The recovery of human CD62L spiked to three different levels throughout the range of the assay in various matrices was evaluated.

Sample Type		Average% of Expected	Range (%)
Human plasma	1:12,800	96	92-104
	1:25,600	97	86-108
Cell culture supernatant	1:128	89	83-94
	1:256	87	80-95

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 plasma was initially diluted 1:1,600. The cell culture supernatant was initially diluted 1:16.)

		Human plasma	Cell culture supernatant
1:2	Average% of Expected	100	100
	Range (%)	-	-
1:4	Average% of Expected	103	105
	Range (%)	102-104	104-106
1:8	Average% of Expected	102	106
	Range (%)	102-103	105-108
1:16	Average% of Expected	118	107
	Range (%)	112-124	105-109

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human CD62L produced at Sunlong Medical™.