DESCRIPTION

CNR2, also known as Cannabinoid Receptor 2 (CB2), is a G protein-coupled receptor (GPCR) of the endocannabinoid system predominantly expressed in immune tissues such as the spleen and leukocytes. Activated by endogenous cannabinoids like 2arachidonoylglycerol (2-AG) and anandamide (AEA), CNR2 couples to Gi/o proteins, inhibiting adenylyl cyclase and modulating MAPK and PI3K/AKT signaling. It regulates immune cell migration, cytokine release, and inflammatory responses. In cancer, CNR2 signaling shows dual roles: it can suppress tumor growth and angiogenesis, yet under certain conditions may enhance tumor survival and immune evasion. Owing to its limited expression in the CNS and non-psychoactive profile, CNR2 is a promising therapeutic target for inflammatory diseases, neuropathic pain, and cancer immunotherapy.

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	10.45	0.18	1.72
2	8	2.70	0.07	2.62
3	8	0.82	0.03	3.44

Inter-assay Precision

Sample	n	Mean (ng/mL)	SD	CV%
1	16	10.30	0.46	4.44
2	16	2.71	0.11	4.07
3	16	0.81	0.04	4.47

RECOVERY

The recovery of human CNR2 spiked to three different levels throughout the range of the assay in cell lysate was evaluated.

Sample Type		Average% of Expected	Range (%)
Cell lysate	1:4	119	117-123
	1:8	111	101-118

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 cell lysate was initially diluted 1:2.)

		Cell lysate
1:2	Average% of Expected	100
	Range (%)	-
1:4	Average% of Expected	112
	Range (%)	109-115
1:8	Average% of Expected	93
	Range (%)	76-110
1:16	Average% of Expected	109
	Range (%)	108-110

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human Human CNR2 Sandwich ELISA Kit produced at Sunlong Medical™.