Human G-CSF ELISA Kit

Granulocyte-colony stimulating factor (G-CSF) is a 24-25 kDa monomeric glycoprotein that regulates the proliferation, differentiation, and activation of hematopoietic cells in the neutrophilic granulocyte lineage. Mature human G-CSF is a 178 amino acid (aa) O-glycosylated protein that contains two intrachain disulfide bridges. In humans, alternate splicing generates a second minor isoform with a 3 aa deletion. Mouse and human G-CSF share 76% aa sequence identity, and the two proteins show species cross-reactivity. G-CSF is produced by activated monocytes and macrophages, fibroblasts, endothelial cells, astrocytes, neurons, and bone marrow stroma cells. In addition, various tumor cells express G-CSF constitutively. Human G-CSF receptor (G-CSF R) is a 120 kDa type I transmembrane glycoprotein that belongs to the hematopoietin receptor superfamily. The mature protein consists of a 603 aa extracellular domain (ECD), a 23 aa transmembrane segment, and a 186 aa cytoplasmic domain. The ECD contains an N-terminal Ig-like domain, a cytokine receptor homology domain, and three fibronectin type III domains. Alternate splicing of human G-CSF R generates additional isoforms including a potentially soluble form of the receptor. The ECDs of mouse and human G-CSF R share 63% aa sequence identity. G-CSF R forms a complex with the ligand in a 2:2 ratio. It is expressed on monocytes, neutrophils, megakaryocytes, platelets, myeloid progenitors, trophoblasts and placenta, endothelial cells, and various tumor cell types. G-CSF is an important regulator for granulopoiesis in vivo, and mutations in G-CSF R are associated with congenital neutropenia. G-CSF can support the growth of multilineage hematopoietic progenitor cells and mobilize them from the bone marrow into the bloodstream. G-CSF enhances the functional capacity of mature neutrophils and supports their survival by limiting the rate of apoptosis. G-CSF also enhances M-CSF induced monocytopoiesis from hematopoietic progenitor cells and stimulates the proliferation of peripheral Th2-inducing dendritic cells. It promotes the development of T cell immune tolerance as well as tissue recovery following myocardial infarction and cerebral ischemia.

pg/ml	O.D.		Average	Corrected
0.00	0.0148	0.0144	0.0146
8.19	0.0336	0.0353	0.0345	0.0199
20.48	0.0645	0.0670	0.0658	0.0512
51.20	0.1376	0.1524	0.1450	0.1304
128.00	0.3456	0.3250	0.3353	0.3207
320.00	0.8238	0.8329	0.8284	0.8138
800.00	1.7270	1.9720	1.8495	1.8349
2000.00	3.5990	3.7930	3.6960	3.6814

	Intra-assay Precision			Inter-assay Precision
Sample Number	S1	S2	S3	S1	S2	S3
	22	22	22	6	6	6
Average(pg/ml)	49.6	227.9	737.9	43.6	210.6	661.4
Standard Deviation	2.9	6.7	49.3	1.2	9.5	18.9
Coefficient of Variation(%)	5.9	2.9	6.7	2.6	4.5	2.9

Intra-assay Precision (Precision within an assay) Three samples of known concentration were tested twenty times on one plate to assess intra-assay precision.
Inter-assay Precision (Precision between assays) Three samples of known concentration were tested six times on one plate to assess intra-assay precision.

The spike recovery was evaluated by spiking 3 levels of human G-CSF into health human serum sample. The un-spiked serum was used as blank in this experiment. The recovery ranged from 80% to 119% with an overall mean recovery of 101%.

Sample Matrix	Sample Evaluated	Range (pg/ml)	Detectable (%)	Mean of Detectable (pg/ml)
Serum	30	0.72-42.44	100	6.93

Serum/Plasma – Thirty samples from apparently healthy volunteers were evaluated for the presence of G-CSF in this assay. No medical histories were available for the donors.