DESCRIPTION

TGF-beta is a member of the transforming growth factor beta (TGFB) family of cytokines, which are multifunctional peptides that regulate proliferation, differentiation, adhesion, migration, and other functions in many cell types. TGF-beta is produced by a number of cell types including regulatory T cells, fibroblasts, epithelial cells, and endothelial cells. TGF-beta acts synergistically with TGFA in inducing transformation. It also acts as a negative autocrine growth factor. TGF-beta plays an important role in bone remodeling as it is a potent stimulator of osteoblastic bone formation, causing chemotaxis, proliferation and differentiation in committed osteoblasts. TGF-beta appears to promote late stage progression and metastasis in some cancers.

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	1,030.1	22.0	2.1
2	8	258.2	6.4	2.5
3	8	129.0	3.8	2.9

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	16	1,036.5	20.7	2.0
2	16	260.8	11.9	4.6
3	16	127.0	4.6	3.6

RECOVERY

The recovery of human TGF-beta1 spiked to three different levels throughout the range of the assay in in various matrices was evaluated.

Sample Type		Average% of Expected	Range (%)
Human serum	1:640	97	95-99
	1:1,280	96	94-98
Urine	1:2.8	79	74-85

LINEARITY

To assess the linearity of the assay, urinet samples were spiked with high concentrations of human TGF beta 1 and diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay. Human serum samples were diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay. (The activated human serum was initially diluted 1:40. )

		Human serum	Urine
1:2	Average% of Expected	100	97
	Range (%)	-	91-103
1:4	Average% of Expected	108	94
	Range (%)	107-109	91-96
1:8	Average% of Expected	118	103
	Range (%)	114-121	102-105
1:16	Average% of Expected	124	107
	Range (%)	120-128	105-108

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human TGF beta 1 produced at Sunlong Medical™.