Recombinant human IL-33 protein - Bioactive cytokine

Human IL-33 protein - E. coli -expressed, tag-free, carrier-free

Recombinant human IL-33 is a high-quality and biologically active cytokine, validated using proprietary IL-33 reporter cells. This member of the IL-1/TLR cytokine superfamily is produced in E. coli and thoroughly purified to remove endotoxins.

Recombinant human IL-33 can be used together with HEK-Blue™ IL-33 cells for the screening of inhibitory molecules, such as Astegolimab, a therapeutic monoclonal antibody targeting the IL-1R4 (ST2) subunit of the IL-33 receptor (see figures).

IL-33 signaling and biological functions

Key features

• Each lot is validated using HEK-Blue™ IL-33 cells
• Endotoxin ≤ 0.1 EU/µg
• 0.2 µm sterile-filtered

Applications

• Standard for IL-33 detection and quantification assays
• Screening and release assays for antibodies blocking IL-33 signaling
• Screening and release assays for engineered IL-33

Interleukin 33 (IL-33), a member of the IL‐1 cytokine family, functions as an alarmin, playing a crucial role in immune responses. It has emerged as a key regulatory cytokine in barrier tissues, making it an important target for inhibition therapy in autoimmune diseases such as inflammatory bowel disease (IBD), rhumatoid arthgritis (RA), asthma, and allergies.

 More details

All InvivoGen products are for internal research use only, and not for human or veterinary use.

Figures

SDS- PAGE analysis of the recombinant human (h)IL-33. 2 μg of hIL-33 was loaded on a 12% Mini-PROTEAN® TGX Stain-Free™ Precast Gel (Bio-Rad). Detection was performed as per the manufacturer’s instructions. A band was detected at ~17 kDa.

Dose-response of HEK-Blue™ IL-33 cells to recombinant human IL-33. HEK-Blue™ IL-33 cells (cat code: hkb-hil33) were stimulated with increasing concentrations of recombinant human IL-33. After overnight incubation, the NF-kB/ AP1-induced SEAP activity was determined using QUANTI-Blue™, a SEAP detection reagent. Data are shown as optical density (OD) at 650 nm (mean ± SEM).

Dose-dependent inhibition of HEK-Blue™ IL-33 cell response using Astegolimab biosimilar. HEK-Blue™ IL-33 cells were incubated with increasing concentrations of Anti-hIL-33R-hIgG2 (0.3 ng - 10 µg) for 1 h prior to the addition of recombinant human IL-33 (30 pg/ml). After overnight incubation, SEAP activity in the cell culture supernatant was assessed using QUANTI-Blue™ Solution. Data are shown in percentage of activity (mean ± SEM).

Specifications

Source: E. coli

Species: Human

Alternative names: Interleukin-1 family member 11 (IL-1F11), Nuclear factor from high endothelial venules (NF-HEV)

Carrier: Carrier-free

Tag: Tag-free

Accession number: O95760

Molecular weight: ~ 17 kDa (SDS-PAGE)

Solubility: 100 μg/ml in water

Formulation: Phosphate buffer saline (pH 7.4)

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.

Tested applications: Cellular assays

Quality control: Each lot is functionally tested and validated.

Contents

Recombinant human IL-33 is provided as a lyophilized powder and is available in two quantities:

• rcyec-hil33​: 10 μg 
• rcyec-hil33-5: 50 μg (5 x 10 μg)
• 1.5 ml endotoxin-free water for rcyec-hil33 and rcyec-hil33-5

 Recombinant human IL-33 is shipped at room temperature.

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

 Avoid repeated freeze-thaw cycles.

Details

Interleukin-33 background

Interleukin-33 (IL-33; also known as IL-1F11, DVS22, NF-HEV)) is a member of the IL-1/Toll-like receptor cytokine superfamily, a group of cytokines that play important roles in host defense, immune regulation, and inflammation [1, 2].

IL-33 is constitutively expressed in lymphoid tissues, epithelial cells, fibroblasts, mucosal tissues, tumor cells, and vascular tissues [3]. It plays a central role in type 2 innate and adaptive immunity and inflammation, modulating Th2, ILC2 and M2 macrophage responses [2]. It is involved in responses to type 2 infections (e.g. parasites), tissue repair, as well as harmful allergic responses (e.g. asthma) [2].

IL-33 mediates its biological effects through the IL-1R4 receptor (also known as ST2, IL1RL1, IL-33R) and the IL-1R3 accessory protein (also known as IL-1RAcP or IL-1RAP) [2, 4, 5]. Upon ligand binding, IL-1Rs dimerize through their Toll/interleukin-1 resistance (TIR) domains to recruit the MyD88 adaptor protein, which then couples to IL-1R-associated kinases (IRAKs) and tumor necrosis factor receptor-associated factor 6 (TRAF6). This leads to the activation of key transcription factors, including NF-KB, AP-1, and IRFs [2, 4].

IL-33 can function both as a traditional cytokine and as a nuclear factor regulating gene transcription. Following pro-inflammatory stimulation, IL-33 can induce Th2-biased immune responses, such as the production of IL-4, IL-5 and IL-13 [6]. In addition, as IL-33 is constitutively expressed in endothelial and epithelial cells, it can act as an endogenous danger signal, or damage-associated molecular pattern (DAMP; also called alarmins), in response to tissue damage [7, 8]. 

IL-33 has emerged as a key regulatory cytokine in barrier tissues, making it an important target for inhibition therapy in autoimmune diseases such as inflammatory bowel disease (IBD), rheumatoid arthritis (RA), asthma, and allergies.

1. Arend W. et al., 2008. IL-1, IL-18, and IL-33 families of cytokines. Immunol Rev. 223:20-38.
2. Mantovani, A., et al., 2019. Interleukin-1 and Related Cytokines in the Regulation of Inflammation and Immunity. Immunity. 50(4): p. 778-795.
3. Catalan-Dibene, J. et al., 2018. Interleukin 30 to Interleukin 40. J Interferon Cytokine Res. 38(10):423-439.
4. Teufel, L.U., et al., 2022. IL-1 family cytokines as drivers and inhibitors of trained immunity. Cytokine. 150: p. 155773.
5. Gaballa, J.M., et al., 2024. International nomenclature guidelines for the IL-1 family of cytokines and receptors. Nature Immunology. 25(4): p. 581-582.
6. Schiering C. et al., 2014. The alarmin IL-33 promotes regulatory T-cell function in the intestine. Nature. 513(7519):564-8.
7. Cayrol C. & Girard JP., 2014. IL-33: an alarmin cytokine with crucial roles in innate immunity, inflammation and allergy. Curr Opin Immunol. 31-7.
8. Oboki K. et al., 2011. IL-33 and airway inflammation. Allergy Asthma Immunol Res. 3(2): 81–88.