Recombinant human IL-2 protein - Bioactive cytokine

Human IL-2 protein - Mammalian cell-expressed, tag-free, carrier-free

Recombinant human IL-2 is a high-quality and biologically active cytokine, validated using proprietary IL-2 reporter cells. This T-cell-regulating cytokine of the γc superfamily is produced in CHO cells to ensure protein glycosylation and bona fide 3D structure.
Note: Invivogen's recombinant human IL-2 does not feature the C125S mutation of Aldesleukin (Proleukin®). This mutation, in which serine has replaced the cysteine at position 125, was introduced to stabilize the E. coli-derived cytokine [1]. 

Recombinant human IL-2 can be used together with HEK-Blue™ IL-2/IL-15 cells for the screening of inhibitory molecules, such as Basiliximab, a therapeutic monoclonal antibody targeting the IL-2Rα subunit of the IL-2 receptor (see figures).

IL-2 signaling and biological functions

Key features

• Natural wildtype human IL-2
• Each lot is validated using HEK-Blue™ IL-2/IL-15 cells
• Endotoxin ≤ 0.1 EU/µg
• 0.2 µm sterile-filtered

Applications

• T cell and NK cell activation and propagation
• IL-2 detection and quantification assays (positive control)
• Screening and release assays for antibodies blocking IL-2 signaling
• Screening and release assays for engineered IL-2 proteins

Interleukin 2 (IL-2) is a pleiotropic cytokine showing immunostimulatory or immunoinhibitory activity, depending on the target cell. In the 1990s, the recombinant IL-2 Aldesleukin became the first FDA-approved immunotherapeutic drug for treating metastatic renal cell carcinoma and metastatic melanoma.

 More details

InvivoGen’s products are for research use only, and not for clinical or veterinary use.

Read our review on IL-2: The Activator and Controller

Reference:

1. Wrangle JM, et al., 2018. IL-2 and Beyond in Cancer Immunotherapy. J Interferon Cytokine Res.;38(2):45-68.

Figures

SDS PAGE of the recombinant human (h)IL-2 protein. 2 μg of hIL-2 was loaded on a 12% Mini-PROTEAN® TGX Stain-Free™ Precast Gel (Bio-Rad). Detection was performed as per the manufacturer’s instructions.

Dose-response in HEK-Blue™ IL-2/IL-15 cells to recombinant IL-2 cytokine. Cells were stimulated with increasing concentrations of recombinant human IL-2. After overnight incubation, the STAT5-induced SEAP activity was determined using QUANTI-Blue™, a SEAP detection reagent. Data are shown as optical density (OD) at 650 nm (mean ± SEM).

Specifications

Source: Chinese hamster ovary (CHO) cells

Species: Human

Alternative name: Aldeleuskin, Proleukin, T cell growth factor, TCGF

Carrier: Carrier-free

Tag: Tag-free

Accession number: P60568.1

Protein size: 133 a.a. (A21-T153)

Molecular weight: ~ 15 kDa (SDS-PAGE)

Solubility: 100 μg/ml in water

Formulation: Phosphate buffer saline (pH 7.4), 5% saccharose

Sterility: 0.2 µm filtration

Form:  Lyophilized

Reconstitution buffer:  Endotoxin-free water (provided)

Purity:  ≥95% (SDS-PAGE)

Endotoxin:  The absence of bacterial contamination (e.g. lipoproteins and endotoxins) has been confirmed using HEK-Blue™ TLR2 and HEK‑Blue™ TLR4 cells.

IU/mg: > 1 x 10⁶ IU/mg

Note: Please refer to the corresponding Certificate of Analysis (CoA) for the exact value. Each lot is tested with the reference standard for human IL-2 (NIBSC code 86/500) for reproducible cell culture conditions without the need for time-consuming lot-to-lot testing.

Tested applications: Cellular assays

Quality control: Each lot is functionally tested and validated

Contents

Recombinant human IL-2 is provided lyophilized and is available in three quantities:

• rcyc-hil2-01: 10 µg
• rcyc-hil2-05: 5 x 10 µg (50 µg)
• rcyc-hil2-2: 2 x 50 µg (100 µg)
• rcyc-hil2-5: 5 x 50 µg (250 µg)

​Each product is provided with endotoxin-free water:

• 1.5 ml endotoxin-free water for rcyc-hil2-01, rcyc-hil2-05, and rcyc-hil2-2. 
• 2 x 1.5 ml endotoxin-free water for rcyc-hil2-5

 Recombinant hIL-2 is shipped at room temperature.

 Upon receipt, the product should be stored at -20°C.

 Avoid repeated freeze-thaw cycles.

Details

Interleukin 2

Interleukin 2 (IL-2) is a pleiotropic cytokine showing immunostimulatory or immunoinhibitory activity, depending on the target cell [1]. It is mainly produced by activated CD4+ T cells in response to antigen stimulation. To a lower extent, it can also be produced by CD8+ T cells and innate immune cells, such as activated dendritic cells (DCs), mast cells, monocytes, and natural killer (NK) cells [1]. IL-2 acts on lymphocytes by binding to the multimeric IL-2 receptor (IL-2R) and thereby engaging several intracellular signaling pathways that modulate lymphocyte survival, proliferation, and function [2].

IL-2 receptor signaling

The IL2R consists of a hetero-complex of up to three subunits: α (IL-2RA), β (IL-2RB), and γ (IL-2RG), also known as CD25, CD122, and CD132, respectively. The γ subunit CD123 is also referred to as the “common” chain (labeled “γc”), as it is shared with the receptors for IL-4, IL-7, IL-9, IL-15, and IL-21 [1]. Due to its high affinity, IL-2 preferentially binds to the trimeric IL-2R, which is mainly expressed on immunosuppressive regulatory T (Treg) cells [1,3]. Interestingly, IL-2 exists in different conformations that favor either trimeric or dimeric IL-2R, resulting in the activation of different immune cells [4].

Upon receptor-ligand binding, the Janus kinase JAK3 phosphorylates JAK1, which in turn recruits SYK (spleen-associated tyrosine kinase). This leads to the phosphorylation and dimerization of the signal transducer and activator of transcription 5A/B (STAT5A/B). After its translocation to the nucleus, it regulates genes encoding immune-related factors such as IL2RA itself, Treg regulator FOXP3, or suppressor of cytokine signaling 1 or 2 (SOCS1/2). IL-2 also activates the Ras/MAPK and PI3K/Akt signaling pathways [1,5].

IL-2 therapeutic targeting

In the 1990s, recombinant IL-2 at high dosage became the first US FDA (Food and Drug Administration) approved immunotherapeutic drug for the treatment of metastatic renal cell carcinoma (RCC) and metastatic melanoma [2]. However, its adverse side effects together with its stimulatory action on immunosuppressive Tregs quickly put the brakes on the initial euphoria [3]. Combinatorial therapy of recombinant IL-2 and immune checkpoint targeting monoclonal antibodies (e.g. anti-CTLA4, PD-1) was reported to overcome these off-target effects and improve response rates [2]. 

Interestingly, low-dose IL-2 therapy has been shown to ameliorate autoimmune diseases and graft-versus-host disease (GvHD) [4]. Autoimmune diseases, such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are caused by an imbalance between Tregs and Teffs, both of which are activated by IL-2 [6]. Selective antibodies against IL-2 can alter its conformation, thereby resulting in the selective expansion of Tregs or Teffs subsets [4,6]. 

The IL-2 cytokine, together with IL-7 and IL-15, is currently under investigation for application in ex vivo T cell expansion. These cytokines are used in different concentrations and combinations to improve cell viability, proliferation, and differentiation in CAR T cell culture [8]. 

Despite its complexity, IL-2-derived therapy remains a promising area of research, with more than 500 clinical trials listed (ClinicalTrials.gov) [7], investigating new and safer IL-2-related reagents in the fight against cancer and autoimmune diseases [2]. 

References:

1. Pol JG, et al., 2020. Effects of interleukin-2 in immunostimulation and immunosuppression. J Exp Med. 217(1):e20191247.
2. Wrangle JM, et al., 2018. IL-2 and Beyond in Cancer Immunotherapy. J Interferon Cytokine Res.;38(2):45-68.
3. Hernandez R, et al., 2022. Engineering IL-2 for immunotherapy of autoimmunity and cancer. Nat Rev Immunol. (10):614-628.
4. Trotta E, et al., 2018. A human anti-IL-2 antibody that potentiates regulatory T cells by a structure-based mechanism. Nat Med.:1005-1014.
5. Ross SH, Cantrell DA,. 2018. Signaling and Function of Interleukin-2 in T Lymphocytes. Annu Rev Immunol.;36:411-433.
6. Yokoyama Y, et al., 2018. IL-2-Anti-IL-2 Monoclonal Antibody Immune Complexes Inhibit Collagen-Induced Arthritis by Augmenting Regulatory T Cell Functions. J Immunol. ;201(7):1899-1906. 
7. Raeber et al., 2022. A systematic review of interleukin-2-based immunotherapies in clinical trials for cancer and autoimmune diseases. medRxiv preprint version.
8. Sudarsanam H, et al., 2022. Influence of Culture Conditions on Ex Vivo Expansion of T Lymphocytes and Their Function for Therapy: Current Insights and Open Questions. Front Bioeng Biotechnol.;10:886637