DESCRIPTION

The C-C motif chemokine ligand 22 (CCL22), also known as MDC, belongs to the group of chemokines, that are both constitutively expressed under homeostatic conditions and inducible upon inflammation. CCL22 is a secreted protein that exerts chemotactic activity for monocytes, dendritic cells, natural killer cells, and for chronically activated T lymphocytes. CCL22 is induced by LPS, IL-4, and IL-13 and in T cells by TCR stimulation. Accumulating studies indicate that CCL22 recruits regulatory T (T-reg) cells into tumor tissues and is expressed in many human tumors.

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	901.0	36.4	4.0
2	8	208.5	15.0	7.2
3	8	97.6	1.7	1.7

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	16	916.9	32.0	3.5
2	16	206.0	13.1	6.4
3	16	97.3	2.4	2.5

RECOVERY

The recovery of human CCL22/MDC spiked to three different levels throughout the range of the assay in human plasma was evaluated.

Sample Type		Average% of Expected	Range (%)
Human plasma	1:16	111	101-120

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.

		Human plasma
1:2	Average% of Expected	100
	Range (%)	-
1:4	Average% of Expected	103
	Range (%)	97-110
1:8	Average% of Expected	95
	Range (%)	83-106
1:16	Average% of Expected	91
	Range (%)	73-109

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human Human CCL22/MDC One-Step ELISA Kit produced at Sunlong Medical™.