DESCRIPTION

CD4 is a transmembrane glycoproteinof the immunoglobulin super-family (IgSF), containing four extracellular Ig-like domains, ahydrophobic transmembrane region and a 40-residue cytoplasmictail. CD4 is expressed T helper cells, majority of thymocytes, monocytes, macrophages, and dendritic cells.CD4 is an accessory protein for MHC class-II antigen/T-cell receptor interactionand it is involved in T cell differentiation, development and activation by interacting with antigen-presenting cells (APCs). The cytoplasmic tail of CD4 associates with the Lck kinase, which in turn activates the signaling components of the T cell receptor (TCR)-CD3 complexes.CD4 also serves as a receptor for human immunodeficiency virus (HIV) by binding to the viral envelope glycoprotein gp120.

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 20 times on one plate to assess intra-assay precision. Inter-assay Precision (Precision between assays) Three samples of known concentration were tested in 24 separate assays to assess inter-assay precision.

Intra-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	20	469.6	11.4	2.4
2	20	133.7	5.0	3.7
3	20	37.7	2.7	7.2

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	24	495.4	42.7	8.6
2	24	138.1	10.9	7.9
3	24	40.0	3.7	9.3

RECOVERY

The recovery of human CD4 spiked to three different levels throughout the range of the assay in various matrices was evaluated.

Sample Type		Average% of Expected	Range (%)
Human serum	1:4	75	71-80
Cell lysate	1:160	99	84-107
	1:320	106	102-111

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 1:80.)

		Human serum	Cell lysate
1:2	Average% of Expected	100	100
	Range (%)	-	-
1:4	Average% of Expected	119	102
	Range (%)	118-120	101-103
1:8	Average% of Expected	112	104
	Range (%)	111-112	102-106
1:16	Average% of Expected	106	102
	Range (%)	87-118	100-104

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human CD4 produced at Sunlong Medical™.

Ordering & shipping

• Minimum order: 1 kit
• Lead time: varies with order quantity and specifications. Please consult your local distributor or our sales team for confirmation
• Payment: T/T 100% in advance; PayPal; Alibaba Trade Assurance
• Shipping: FedEx / DHL / UPS express; cold-chain packing available on request
• Price: USD, per kit (48T / 96T options available)