DESCRIPTION

MICA (MHC class I chain-related A) protein is a stress-induced molecule expressed on epithelial cells and fibroblasts. It activates NK cells and T cells via the NKG2D receptor, playing a vital role in immune surveillance against cancer and infections. MICA is also implicated in autoimmune diseases and transplant rejection. Its polymorphisms can affect immune responses and disease susceptibility.

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	805.5	44.5	5.5
2	8	154.7	11.2	7.3
3	8	92.3	9.0	9.7

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	16	817.7	37.1	4.5
2	16	172.2	21.4	12.4
3	16	90.4	7.6	8.5

RECOVERY

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

Sample Type		Average% of Expected	Range (%)
Human serum	1:16	90	86-94
	1:32	98	94-101
Cell culture supernatant	1:4	85	80-89

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 1:2.)

		Human serum	Cell culture supernatant
1:2	Average% of Expected	100	100
	Range (%)	-	-
1:4	Average% of Expected	113	103
	Range (%)	112-113	100-107
1:8	Average% of Expected	108	106
	Range (%)	100-115	100-113
1:16	Average% of Expected	110	105
	Range (%)	94-127	89-121

CALIBRATION

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