Recombinant Human IL-1ra

Recombinant Human IL-1ra (Interleukin-1 receptor antagonist) is a valuable tool for research applications due to its well-characterized biological activity and broad relevance in immunology, inflammation, and disease modeling. Here are several key reasons to use Recombinant Human IL-1ra in your research:

1. Modulates IL-1–Mediated Inflammation

IL-1ra specifically blocks the activity of IL-1 (both IL-1α and IL-1β) by competitively binding to the IL-1 receptor (IL-1R1) without activating it. This inhibition suppresses downstream inflammatory signaling, making IL-1ra ideal for studying the role of IL-1 in immune responses, both in vitro and in vivo [1, 4, 9].

2. Validated in Disease Models

Recombinant IL-1ra has been used in pre-clinical studies to investigate its therapeutic potential in a range of inflammatory and autoimmune diseases, including:

• Rheumatoid arthritis
• Sepsis
• Chronic myelogenous leukemia
• Autoinflammatory syndromes
• Organ damage (e.g., liver injury)[4, 7, 11]

3. Therapeutic Relevance

IL-1ra (marketed as anakinra) is clinically approved for several autoimmune and inflammatory conditions. Using recombinant IL-1ra in research allows for translational studies that bridge basic science and clinical applications, including drug development and biomarker discovery [3, 8, 12].

4. Mechanistic Studies

IL-1ra is a critical tool for dissecting the IL-1/IL-1ra axis in inflammation, immune regulation, and tissue homeostasis. It enables researchers to:

• Determine the contribution of IL-1 signaling in specific disease contexts
• Investigate the effects of IL-1 blockade on cytokine networks, cell migration, and tissue repair
• Study the impact of IL-1 inhibition on vaccine-induced inflammation and immune responses [3, 10]

5. Biomarker and Predictive Studies

Recent studies have shown that baseline levels of IL-1ra can predict patient response to IL-1–targeted therapies, especially in sepsis. Using recombinant IL-1ra in experimental models can help identify and validate biomarkers for patient stratification and treatment efficacy .

6. Safety and Tolerability

Recombinant IL-1ra is well tolerated in both animal and human studies, with a short half-life that makes it suitable for acute and controlled experimental interventions .

7. Versatile Applications

Recombinant IL-1ra can be used in a variety of experimental settings, including:

• Cell culture assays (e.g., inhibition of IL-1–induced cytokine production)
• Animal models of inflammation and autoimmunity
• Bioassays and binding studies
• Studies of tissue repair and regeneration [4, 5, 9]

In summary, Recombinant Human IL-1ra is a powerful and versatile reagent for studying inflammation, immune regulation, and disease mechanisms. Its ability to specifically inhibit IL-1 signaling makes it essential for both basic research and translational studies in immunology and inflammatory diseases.

Yes, recombinant human IL-1ra can be used as a standard for quantification and calibration in ELISA assays, though there are important considerations regarding its specific application and formulation.

Suitability as an ELISA Standard

Recombinant human IL-1ra produced in E. coli expression systems is specifically designed and validated for use as an ELISA standard. The recombinant protein consists of 153 amino acid residues with a molecular weight of approximately 17.2 kDa. When used as a calibration standard, it has been demonstrated to accurately quantitate both recombinant and natural human IL-1ra in biological samples.

Standard Curve Preparation

When preparing your standard curve, dilute the recombinant IL-1ra stock solution in the appropriate assay diluent to create serial dilutions across your desired concentration range. Typical ELISA assays for IL-1ra operate with detection ranges between 25-1600 pg/mL, with sensitivities achieving limits of detection below 7 pg/mL. The recombinant standard should demonstrate linear dose-response relationships with high precision, typically showing intra-assay coefficients of variation between 3.7-7.3% and inter-assay coefficients of variation between 5.7-11%.

Formulation Considerations

For ELISA applications specifically, recombinant IL-1ra formulated with bovine serum albumin (BSA) is recommended as the appropriate choice for use as an ELISA standard. This formulation provides stability and consistency across multiple assay runs.

Important Limitation

It is critical to note that ELISA standard recombinant proteins are not recommended for bioassay applications and should not be used for functional or biological activity testing, as they are not validated for these purposes. Ensure you are using the protein exclusively for quantitative ELISA calibration rather than for cell-based functional assays.

Recombinant Human IL-1ra has been validated for a broad range of applications in published research, including both experimental and therapeutic contexts. Key validated applications are:

• Functional Assays: Used to assess biological activity, particularly its ability to block IL-1-induced inflammatory responses in vitro and in vivo.
• Bioassays: Employed to measure cytokine activity, cell signaling, and immune modulation in various cell types and tissues.
• Blocking Assays: Utilized to inhibit IL-1 signaling in cell culture and animal models, demonstrating its antagonistic effect on IL-1 receptors.
• Western Blot: Used for protein detection and quantification in research settings.
• ELISA (Enzyme-Linked Immunosorbent Assay): Applied for quantifying IL-1ra levels in biological samples.
• Cell Culture: Used to study cellular responses to IL-1 inhibition, including effects on proliferation, apoptosis, migration, and cytokine production.
• Preclinical and Clinical Therapeutic Studies: Validated in models and trials for diseases such as rheumatoid arthritis, systemic juvenile idiopathic arthritis (JIA), sepsis, chronic myelogenous leukemia, osteoarthritis, and various autoinflammatory syndromes.
• Imaging Studies: Used in PET imaging to track anti-inflammatory effects in animal models.

Disease Models and Therapeutic Applications:

• Rheumatoid Arthritis: Extensively validated as a therapeutic agent, including dose-ranging and efficacy studies.
• Systemic JIA: Used as first-line therapy in clinical studies.
• Osteoarthritis: Investigated in gene therapy trials for intra-articular delivery.
• Sepsis, Chronic Myelogenous Leukemia, Kawasaki Disease, Behçet's Disease, Macrophage Activation Syndrome, Myocardial Injury, Pericarditis, Gout, Atopic Dermatitis, Melanoma, Severe COVID-19 Pneumonia: Demonstrated efficacy in preclinical and clinical research.

Experimental Contexts:

• Cellular Mechanism Studies: Used to dissect IL-1 signaling pathways, immune cell activation, and cytokine regulation in cancer, infectious disease, and neuroinflammation models.
• Animal Models: Validated for anti-inflammatory effects in rodent models of chronic inflammation and autoimmune disease.

Summary Table:

In summary, recombinant human IL-1ra is a well-validated reagent for both basic research and translational/clinical studies, with applications spanning molecular assays, cell biology, animal models, and human therapeutics.

To reconstitute and prepare Recombinant Human IL-1ra protein for cell culture experiments, follow these best-practice steps:

• Centrifuge the vial briefly (e.g., 3000 rpm for 5 minutes) before opening to ensure all lyophilized protein is at the bottom.
• Warm the vial to room temperature before opening to minimize condensation.
• Reconstitute the protein by gently adding sterile water or sterile PBS. The most common recommended concentration is 0.1 mg/mL (100 μg/mL). If the product is carrier-free, use sterile PBS; if it contains a carrier protein (e.g., BSA), use the buffer specified in the datasheet.
• Gently mix by pipetting up and down or swirling. Do not vortex or shake vigorously, as this can denature the protein and reduce biological activity.
• Allow the solution to sit at room temperature for 10–20 minutes to ensure complete dissolution.
• Aliquot the reconstituted protein into small volumes to avoid repeated freeze-thaw cycles, which can degrade the protein.
• Storage:
  • Short-term (up to 1 month): 2–8 °C.
  • Long-term (up to 3 months): –20 °C to –80 °C.
  • Avoid multiple freeze-thaw cycles by aliquoting.

Dilution for cell culture:

• Prepare working dilutions in cell culture medium immediately before use. If possible, add a carrier protein (e.g., 0.1% BSA or HSA) to minimize adsorption and loss of activity, especially at low concentrations.

Summary Table:

Additional notes:

• Always consult the specific product datasheet for any unique formulation or buffer requirements, as some preparations may contain stabilizers or require specific buffers.
• For functional assays, confirm the biological activity post-reconstitution using a relevant bioassay (e.g., inhibition of IL-1α-induced proliferation in D10.G4.1 cells).

These steps will help ensure optimal solubility, stability, and biological activity of recombinant human IL-1ra in your cell culture experiments.