Recombinant human IL-6 protein (Qk093)

Interleukin-6 (IL-6) is a multifunctional cytokine that regulates immune responses and inflammation. It is produced by various cells, including immune cells such as T cells and macrophages, as well as non-immune cells like fibroblasts and endothelial cells. 

Human IL6 has a molecular weight of 20.9 kDa. This protein is animal origin-free, carrier-free and tag-free to ensure its purity with exceptional lot-to-lot consistency. Interleukin-6 is suitable for the culture of reproducible and high-quality hematopoietic stem cells and other relevant cells. 

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1000µg will be despatched as 2 x 500µg

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  • High purity human protein (Uniprot number: P05231)

  • >98%, by SDS-PAGE quantitative densitometry

  • Source: Expressed in E. coli 

  • 20.9 kDa monomer

  • Animal origin-free (AOF) and carrier protein-free

  • Manufactured in Cambridge, UK

  • Lyophilized from HEPES/NaCl

  • Resuspend in water at >100 µg/mL, prepare single-use aliquots, add carrier protein if desired, and store frozen at -20oC or -80oC

Featured applications

  • Immune response regulation 

  • Stimulation of B cell differentiation 

  • Stimulation of T cell differentiation 

  • Hematopoiesis regulation 

  • Proliferation and differentiation of erythrocytes, leukocytes and platelets 

  • Inflammation amplification 

B-cell stimulatory factor 2 (BSF-2)
CTL differentiation factor (CDF)
Hybridoma growth factor
Interferon beta-2 (IFN-beta-2)

Frequently used together


Bioactivity graph showing the EC50 of 2.46 pg/ml (70 pM) for Qkine recombinant IL-6

IL6 protein activity is determined using the IL-6-responsive firefly luciferase reporter assay. Transfected HEK293T cells are treated in triplicate with a serial dilution of IL-6 for 24 hours. Firefly luciferase activity is measured and normalised to the control Renilla luciferase activity. Data from Qk093 lot #204594. EC50 = 1.46 ng/mL (70 pM) 


SDS-PAGE gel showing the high purity reduced and non-reduced forms of IL-6 

Recombinant IL-6 migrates as a major band at approximately 20 kDa in non-reducing (NR) and at approximately 18 kDa in reduced (R) conditions. No contaminating protein bands are present. The purified recombinant protein (3 µg) was resolved using 15% w/v SDS-PAGE in reduced (+β-mercaptoethanol, R) and non-reduced (NR) conditions and stained with Coomassie Brilliant Blue R250. Data from Qk093 lot #204599. 

Further quality assays

  • Mass spectrometry, single species with the expected mass

  • Endotoxin: <0.005 EU/μg protein (below the level of detection)

  • Recovery from stock vial: >95%

We are a company founded and run by scientists to provide a service and support innovation in stem cell biology and regenerative medicine.  All our products are exceptionally high purity, with complete characterisation and bioactivity analysis on every lot.

Protein background

Interleukin-6 (IL-6) is a multifunctional cytokine that plays a crucial role in regulating the immune response, inflammation, and various physiological processes. IL-6 is produced by a variety of cells, including T cells, B cells, monocytes, fibroblasts, endothelial cells, and adipocytes [1]. 

IL6 protein is a pleiotropic cytokine that belongs to the interleukin family of proteins. IL-6 adopts a four-helix bundle structure, with helices A and D forming the receptor-binding site [2]. It is glycosylated, influencing stability and activity. IL-6 binds to IL-6 receptor (IL-6R), forming a hexameric complex with gp130, initiating downstream signaling via the JAK/STAT pathway. Conformational changes upon receptor binding facilitate signaling. 

IL-6 has a primary involvement in the acute phase response, the immediate reaction to infection, injury, or inflammation. IL-6 stimulates the production of acute-phase proteins such as C-reactive protein (CRP), fibrinogen, and serum amyloid A, which help to enhance the immune response and facilitate tissue repair [3,4]. 

IL6 protein plays a key role in the regulation of the immune system. It promotes the differentiation of B cells into antibody-producing plasma cells and stimulates the proliferation and activation of T cells, enhancing the adaptive immune response. IL-6 acts on various immune cells to modulate inflammation, promoting the recruitment of immune cells to sites of infection or injury [5,6]. IL-6 has diverse effects on different tissues and organs throughout the body. It has been implicated in the regulation of metabolism, with studies suggesting that IL-6 may play a role in energy balance, glucose metabolism, and lipid metabolism. IL-6 has been shown to have both pro- and anti-inflammatory effects depending on the context and the cells involved [7]. 

Dysregulated IL-6 signaling has been associated with various pathological conditions, including autoimmune diseases, chronic inflammation, and cancer. Elevated levels of IL-6 have been observed in conditions such as rheumatoid arthritis, systemic lupus erythematosus, and inflammatory bowel disease, where it contributes to tissue damage and disease progression [8]. 

[1] Rose-John, S., & Heinrich, P. C. Soluble receptors for cytokines and growth factors: generation and biological function. Biochem. J. 436, 241–259 (2012).

[2] Kishimoto, T. Interleukin-6: Discovery of a pleiotropic cytokine. Arthritis Res. Ther. 12(Suppl 1), S2 (2010).

[3] Tanaka, T., Narazaki, M. & Kishimoto, T. Interleukin-6: From bench to bedside. Nat. Rev. Immunol. 20, 230–244 (2020).

[4] Scheller, J., Chalaris, A., Schmidt-Arras, D., & Rose-John, S. The pro- and anti-inflammatory properties of the cytokine interleukin-6. Biochim. Biophys. Acta – Mol. Cell Res. 1813, 878–888 (2011).

[5] Hunter, C. A., & Jones, S. A. IL-6 as a keystone cytokine in health and disease. Nat. Immunol. 16, 448–457 (2015).

[6] Rincon, M. Interleukin-6: from an inflammatory marker to a target for inflammatory diseases. Trends Immunol. 33, 571–577 (2012).

[7] Tanaka, T. & Kishimoto, T. The biology and medical implications of interleukin-6. Cancer Immunol. Res. 2, 288–294 (2014)

[8] Jones, S. A. & Jenkins, B. J. Recent insights into targeting the IL-6 cytokine family in inflammatory diseases and cancer. Nat. Rev. Immunol. 18, 773–789 (2018).

Additional resources

Our products are for research use only and not for diagnostic or therapeutic use.  Products are not for resale.

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