Recombinant human IL-2 protein

Summary

• Highly pure human IL-2 protein (UniProt number: P60568)15.5
• kDa (monomer)
• >98%, by SDS-PAGE quantitative densitometry
• Expressed in E. coli
• Animal origin-free (AOF) and carrier protein-free
• Manufactured in our Cambridge, UK laboratories
• Lyophilized from acetonitrile, TFA
• Resuspend in sterile-filtered water at >50 µg/ml, add carrier protein if desired, prepare single use aliquots and store frozen at -20 °C (short-term) or -80 °C (long-term).

Featured applications

• Activation of T-cells and natural killer (NK) cells
• Differentiation of T-cells 
• Development and maintenance of regulatory T-cells (Tregs)
• Promotion of the expansion of effector T-cells 

Bioactivity

Recombinant IL-2 activity was determined using the Promega IL-2 Bioassay Kit (JA2201). Cells were treated in triplicate with a serial dilution of IL-2 for 6 hours. Activity was measured using Bio-Glo™ Reagent and readings normalised to the maximum response. Data from Qk089 lot 204686. EC50 = 49 pg/ml (3.2 pM).

Purity

Recombinant IL-2 migrates at approximately 15.5 kDa (monomer) in reduced (R) and non-reduced (NR) 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 Qk089 lot #204686.

Qkine IL-2 is as biologically active as the comparable alternative supplier protein

Qkine IL-2 is as biologically active as the comparable alternative supplier protein. IL-2 bioactivity was determined using the Promega IL-2 bioassay kit. Cells were stimulated with Qkine IL-2 (Qk089, green) and alternative supplier IL-2 (Supplier B, black). Cells were treated in triplicate with a serial dilution of IL-2 for 6 hours. Data from Qk089 lot #204686.

Protein background

Interleukin-2 (IL-2) is a cytokine that plays a vital role in the immune system, particularly in T-cell development, growth, and activity. IL-2 is produced mainly by activated CD4+ T-cells in response to antigenic stimulation and is essential for both immune response amplification and immune regulation [1,2].

IL-2 is a single-chain glycoprotein composed of 133 amino acids with a molecular weight of 15.5 kDa. The IL-2 receptor (IL-2R) is a complex made up of three subunits: IL-2Rα (CD25), IL-2Rβ (CD122), and the common gamma chain (γc, CD132). When IL-2 binds to its receptor, it activates downstream signaling pathways like JAK-STAT and PI3K-AKT, promoting cell survival, proliferation, and differentiation [3].

IL-2 is critical for the expansion of effector T-cells, which are responsible for attacking and eliminating pathogens and cancer cells. It also plays a role in the development and maintenance of regulatory T-cells (Tregs), which prevent autoimmune responses by keeping the immune system in check. IL-2 enhances the activity of natural killer (NK) cells and B-cells, contributing to overall immune defense [4].

IL-2 is used in cancer immunotherapy, particularly for treating metastatic melanoma and renal cell carcinoma, where it boosts the immune system’s ability to attack tumors. Low-dose IL-2 is being investigated for autoimmune diseases such as lupus and type 1 diabetes, where it can promote Treg expansion to restore immune balance. IL-2 has also been explored as a treatment for chronic infections like HIV and hepatitis C by enhancing immune cell recovery and function. Its role as an adjuvant in vaccines and its potential in organ transplantation to promote immune tolerance are also being actively studied [5].

Background references

1. Boyman, O. & Sprent, J. The role of interleukin-2 during homeostasis and activation of the immune system. Nat. Rev. Immunol. 12, 180-190 (2012). https://doi.org/10.1038/nri3156
2. Liao, W., Lin, J. X. & Leonard, W. J. Interleukin-2 at the crossroads of effector responses, tolerance, and immunotherapy. Immunity 38, 13-25 (2013). doi: 10.1016/j.immuni.2013.01.004
3. Arenas-Ramirez, N., Woytschak, J. & Boyman, O. Interleukin-2: Biology, design and application. Trends Immunol. 36, 763-777 (2015). doi: 10.1016/j.it.2015.10.003
4. Spolski, R., Li, P. & Leonard, W. J. Biology and regulation of IL-2: from molecular mechanisms to human therapy. Nat. Rev. Immunol. 18, 648-659 (2018). doi: 10.1038/s41577-018-0046-y
5. Ross, S. H. & Cantrell, D. A. Signaling and function of interleukin-2 in T lymphocytes. Annu. Rev. Immunol. 36, 411-433 (2018). doi: 10.1146/annurev-immunol-042617-053352

FAQ

What is IL-2?
IL-2 is a cytokine that regulates immune responses by promoting the growth and activation of T-cells, enhancing immune function, and maintaining immune tolerance for immune activation and suppression.

Where is IL-2 found?
IL-2 is found in the immune system, produced by activated CD4+ T-cells, CD8+ T-cells, and natural killer cells, primarily within lymphoid tissues like lymph nodes and the spleen.

Is IL-2 a cytokine?
Yes, IL-2 is a cytokine. Cytokines are small proteins that help regulate the immune system, and IL-2 specifically plays a key role in the activation, growth, and proliferation of T-cells and other immune cells.

What does the IL-2 gene do?
The IL-2 gene encodes interleukin-2, a cytokine crucial for T-cell proliferation, activation, and survival, playing a key role in immune response and regulation.

What does IL-2 bind to?
IL-2 primarily binds to the IL-2 receptor (IL-2R), which has three subunits: alpha (CD25), beta (CD122), and gamma (CD132). This binding initiates signaling pathways such as JAK-STAT, MAPK and PI3K-AKT pathways that promote T-cell growth, differentiation, and survival.

What is the function of the IL-2 receptor?
The IL-2 receptor (IL-2R) mediates interleukin-2 signaling, promoting T-cell proliferation, activation, and survival. It regulates immune responses, maintains immune homeostasis, and stimulates other immune cells, contributing to a balanced and effective adaptive immune response.

What is the IL-2 pathway?
The IL-2 pathway involves IL-2 binding to its receptor, activating JAK kinases, which phosphorylate STAT proteins. This triggers gene expression for T-cell proliferation and survival, while also activating MAPK and PI3K-AKT pathways, enhancing overall immune response and regulation.

How is IL-2 used in cell culture?
IL-2 is utilized in cell culture to promote T-cell growth and proliferation, maintaining cell viability by preventing apoptosis. It aids in differentiating T-cell subsets, supports functional assays for cytokine production, and is used in co-culture systems with other immune cells to study immune interactions and responses effectively.