Rat IL-2 ELISA Kit

Interleukin 2 (IL-2), also known as T cell growth factor (TCGF), is a 15-18 kDa variably glycosylated alpha -helical polypeptide that is a member of the Common gamma Chain (gamma c) cytokine family. It exists as a monomer and has a notably short half-life (< 30 minutes). Human IL-2 is synthesized as a 153 amino acid (aa) precursor that contains a 20 aa signal sequence plus a 133 aa mature region. The mature region is alpha -helical in nature, and contains one utilized O-linked glycosylation site at Thr3 plus three cysteines, two of which form an intrachain disulfide bond that is essential for activity. Mature human IL-2 shares 73%, 66%, 78% and 97% aa identity with canine, rat, feline and rhesus monkey IL-2, respectively. Although human IL-2 shares only approximately 60% aa identity with the highly polymorphic mouse IL-2, human IL-2 is known to be active on mouse IL-2 responsive cells. Cells reported to secrete IL-2 include gamma δ T cells, activated conventional CD4+ and CD8+ T cells, neurons, microglia, and hematopoietic stem cells. - The receptor for IL-2 (IL-2 R) is composed of three subunits, the 55 kDa CD25/IL-2 R alpha chain, the 70 kDa IL-2 R beta chain, and the 65 kDa Common gamma Chain. IL-2 first binds to CD25, the binary complex then recruits IL-2 R beta and gamma c to form the quaternary signaling complex. In addition to IL-2, IL-2 R beta is used by IL-15 in its quaternary signaling complex. gamma c also serves as a signaling receptor for IL-4, -7, -9, -15, and -21. - In vitro studies have shown an important role for IL-2 in T cell activation and expansion. In vivo, IL-2 is critical for the development, maintenance and function of regulatory T cells (Treg) which provide protection against autoimmune disease. On the other hand, IL-2 can also promote autoimmune inflammation in target organs through its roles in regulating the expression of T cell trafficking genes, and production of Th2 cytokines. Within the CD8+ T cell subset, IL-2 is essential for optimal primary responses and differentiation into terminal effector cells. IL-2 also promotes the development of activated CD8+ T cells into memory cells.

pg/ml	O.D.		Average	Corrected
0.00	0.0645	0.0636	0.0641
10.97	0.0731	0.0733	0.0732	0.0092
32.92	0.0872	0.0873	0.0873	0.0232
98.77	0.1382	0.1433	0.1408	0.0767
296.30	0.2812	0.2953	0.2883	0.2242
888.89	0.6422	0.6543	0.6483	0.5842
2666.67	1.5432	1.5153	1.5293	1.4652
8000.00	3.0881	3.1932	3.1407	3.0766

	Intra-assay Precision			Inter-assay Precision
Sample Number	S1	S2	S3	S1	S2	S3
	22	22	22	6	6	6
Average(pg/ml)	139	708.7	2461.3	141.5	712.2	2421.2
Standard Deviation	7.5	21.9	120.7	9.3	34.2	130.7
Coefficient of Variation(%)	5.4	3.1	4.9	6.6	4.8	5.4

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 rat IL-2 into health rat serum sample. The un-spiked serum was used as blank in these experiments.

The recovery ranged from 83% to 110% with an overall mean recovery of 95%.

Sample Matrix	Sample Evaluated	Range (pg/ml)	Detectable (%)	Mean of Detectable (pg/ml)
Serum	30	9.9-387.7	50	92.4

Serum/Plasma – Thirty samples from apparently healthy rats were evaluated for the presence of IL-6 in this assay. No medical histories were available for the donors.

n.d. = non-detectable. Samples measured below the sensitivity are considered to be non-detectable.