DESCRIPTION

CD19 is a type I transmembrane glycoprotein belonging to the immunoglobulin superfamily. It is expressed by B cells and follicular dendritic cells. CD19 is up-regulated at the step of B-lineage commitment during the differentiation of the hematopoietic stem cell, it remains on during subsequent stages of differentiation until finally down-regulated during terminal differentiation into plasma cells. CD19 is also involved in B cell development, activation, and differentiation. It is the dominant component for the signaling complex on B cells that includes CD21 (CR2), CD81 (TAPA-1) and CD225 and acts as a critical coreceptor for BCR signal transduction.

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	17.32	1.65	9.52
2	8	3.85	0.19	4.96
3	8	1.99	0.05	2.50

Inter-assay Precision

Sample	n	Mean (ng/mL)	SD	CV%
1	16	16.51	1.58	9.59
2	16	3.74	0.19	4.97
3	16	1.95	0.07	3.41

RECOVERY

The recovery of human CD19 spiked to three different levels throughout the range of the assay in cell lysate was evaluated.

Sample Type		Average% of Expected	Range (%)
Cell lysate	1:40	92	87-96

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 1:2.5.)

		Cell lysate
1:2	Average% of Expected	100
	Range (%)	-
1:4	Average% of Expected	88
	Range (%)	83-93
1:8	Average% of Expected	94
	Range (%)	82-106
1:16	Average% of Expected	105
	Range (%)	95-114

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human Human CD19 Sandwich ELISA Kit 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
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• Price: USD, per kit (48T / 96T options available)