Interleukin 6 (IL-6) is a multifunctional cytokine that plays important roles in host defense, acute phase reactions, immune responses, nerve cell functions and hematopoiesis (1-5). It is expressed by a variety of normal and transformed lymphoid and nonlymphoid cells.

IL-6 is a prototypic member of the IL-6 superfamily of cytokines that share gp130 as a component required for signal transduction (4). The mouse (6), rat (7) and human (8, 9) IL-6 cDNAs have been cloned. The mouse IL-6 cDNA encodes a 211 amino acid (aa) residue precursor polypeptide with a hydrophobic signal sequence that is cleaved to generate the 187 aa residue mature protein. Mouse to rat and human, there is approximately 87% and 39% aa identity, respectively. Although human and mouse IL-6 are equally active on mouse cells, mouse IL-6 is not active on human cells (10).

The high-affinity IL-6 receptor complex, which mediates IL-6 bioactivity, consists of two membrane glycoproteins. The production of IL-6 is upregulated by numerous signals such as mitogenic or antigenic stimulation, lipopolysaccharides, calcium ionophores, cytokines and viruses. IL-4, IL-10 and IL-13 inhibit IL-6 expression in monocytes. Elevated serum IL-6 levels have been observed in a number of pathological conditions, including bacterial and viral infections, trauma, autoimmune diseases, inflammations and malignancies (3, 5).

This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for IL-6 has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any IL-6 present is bound by the immobilized antibody. Following incubation unbound samples are removed during a wash step, and then a detection antibody specific for IL-6 is added to the wells and binds to the combination of capture antibody-IL-6 in sample. Following a wash to remove any unbound combination, and enzyme conjugate is added to the wells. Following incubation and wash steps a substrate is added. A coloured product is formed in proportion to the amount of IL-6 present in the sample. The reaction is terminated by addition of acid and absorbance is measured at 450nm. A standard curve is prepared from seven IL-6 standard dilutions and IL-6 sample concentration determined.

Figure 1:Schematic diagram of the assay

1. Aluminium pouches with a Microwell Plate coated with antibody to mouse IL-6 (8x12)

2. 2 vials mouse IL-6 Standard lyophilized, 500 pg/ml upon reconstitution

3. 2 vials concentrated Biotin-Conjugate anti-mouse IL-6 antibody

4. 2 vials Streptavidin-HRP solution

5. 1 bottle Standard /sample Diluent

6. 1 bottle Biotin-Conjugate antibody Diluent

7. 1 bottle Streptavidin-HRP Diluent

8. 1 bottle Wash Buffer Concentrate 20x (PBS with 1% Tween-20)

9. 1 vial Substrate Solution

10. 1 vial Stop Solution

11. 4 pieces Adhesive Films

12. package insert

NOTE: [96 Tests]

Unopened Kit：Store at 2 -8° C. Do not use past kit expiration date. opened/ReconstitutedReagents：Please refer to the datasheets for detail information.

1. Chiu, C-P. et al. (1988) Proc. Natl. Acad. Sci. USA 85:7099.

2. Northemann, W. et al. (1989) J. Biol. Chem. 264:16072.

3. Hirano, T. et al. (1986) Nature 324:73.

4. Van Snick, J. et al. (1988) Eur. J. Immunol. 18:193.

5. Cayphas, S. et al. (1987) J. Immunol. 139:2965.

6. Hibi, M. et al. (1996) J Mol. Med. 74:1.

7. Hirano, T. et al. (1994) Stem Cells 12:262.

8. Van Snick, J. et al. (1990) Annu. Rev. Immunol. 8:253.

9. Taga, T. and T. Kishimoto (1997) Annu. Rev. Immunol. 15:797.

10. Hirano, T. (1994) “Interleukin 6” in The Cytokine Handbook 2nd ed. Academic Press, New York, p. 145.