Recombinant Human IL-1 RII

Recombinant Human IL-1 RII (Interleukin-1 Receptor Type II) is used in research applications primarily to study and modulate the activity of IL-1, a key pro-inflammatory cytokine, by acting as a decoy receptor that binds IL-1 and prevents its interaction with signaling receptors, thereby inhibiting downstream inflammatory responses.

Key scientific applications and rationale:

• Inflammation and Immune Modulation: IL-1 RII acts as a "decoy" receptor, binding IL-1α and IL-1β with high affinity but lacking a signaling domain, thus preventing IL-1 from activating its primary signaling receptor (IL-1RI). This property makes recombinant IL-1 RII a valuable tool for dissecting IL-1-driven pathways in models of inflammation, autoimmunity, and infection.

• Disease Models: Recombinant IL-1 RII is used to investigate the role of IL-1 in diseases such as rheumatoid arthritis, sepsis, allergic rhinitis, and other inflammatory or autoimmune conditions. By neutralizing IL-1 activity, researchers can assess the contribution of this cytokine to disease pathogenesis and evaluate potential therapeutic strategies.

• Therapeutic Research: Studies using recombinant IL-1 receptor antagonists (such as IL-1Ra, which is mechanistically related to IL-1 RII) have demonstrated efficacy in reducing inflammation, tissue damage, and mortality in animal models and clinical settings, including sepsis and autoimmune diseases. Recombinant IL-1 RII can be used similarly to explore therapeutic potential and mechanisms.

• Biochemical and Cell-Based Assays: Recombinant IL-1 RII is employed in ELISA, Western blot, and bioassays to quantify IL-1, study receptor-ligand interactions, and validate antibody specificity. It is also used to absorb or neutralize IL-1 activity in vitro and in vivo.

Advantages of using recombinant human IL-1 RII:

• Specificity: It binds IL-1α and IL-1β with high affinity, providing a targeted approach to block IL-1 signaling without affecting other cytokines.
• Mechanistic Insight: Enables precise dissection of IL-1-dependent pathways in cellular and animal models.
• Translational Relevance: Findings using recombinant IL-1 RII can inform the development of anti-inflammatory therapies for human diseases.

Summary of best practices:

• Use recombinant IL-1 RII to neutralize IL-1 activity in cell culture or animal models to study the cytokine’s role in inflammation and immunity.
• Employ in combination with other cytokine inhibitors or in genetically modified models to delineate specific pathways.
• Validate the biological activity and specificity of the recombinant protein in your system using appropriate controls and assays.

In summary, recombinant human IL-1 RII is a critical reagent for studying IL-1 biology, dissecting inflammatory mechanisms, and developing or testing anti-inflammatory interventions in preclinical research.

Recombinant Human IL-1 RII can be used as a standard for quantification or calibration in ELISA assays, provided it is compatible with your assay's antibody pair and detection system.

Key considerations and supporting details:

• Intended Use: Recombinant IL-1 RII is commonly supplied as a standard in commercial ELISA kits designed to quantify IL-1 RII in biological samples. These kits use recombinant protein to generate a standard curve, which is then used to determine the concentration of IL-1 RII in unknown samples.

• Parallelism: For accurate quantification, the recombinant standard and the natural protein in your samples must be recognized equivalently by the assay antibodies. Commercial ELISA kits validate that their antibody pairs detect both recombinant and natural IL-1 RII in a parallel manner, ensuring reliable quantification.

• Protein Formulation: The recombinant IL-1 RII standard is typically lyophilized and should be reconstituted according to the manufacturer’s instructions, often in PBS with a carrier protein such as BSA to maintain stability and prevent adsorption.

• Validation: If you are developing your own ELISA or using a non-commercial system, you must validate that your antibody pair recognizes the recombinant standard and the native protein in a parallel fashion. This is typically done by running serial dilutions of both the recombinant standard and a native sample to confirm parallelism of the standard curves.

• Matrix Effects: When quantifying IL-1 RII in complex matrices (e.g., serum, plasma), ensure that the recombinant standard behaves similarly to the native protein in those matrices. Commercial kits report recovery and linearity data to support this.

• Documentation: Always check the Certificate of Analysis or product datasheet for your recombinant IL-1 RII to confirm its suitability as an ELISA standard and to obtain reconstitution and storage instructions.

Summary Table: Use of Recombinant Human IL-1 RII as ELISA Standard

Conclusion:
You can use recombinant human IL-1 RII as a standard for ELISA quantification if your assay is validated for this purpose, and the antibody pair recognizes both recombinant and native forms equivalently. If you are developing your own assay, perform validation experiments to ensure accurate quantification.

Recombinant Human IL-1 RII has been validated for several key applications in published research, including surface plasmon resonance, in vivo studies, antibody absorption, Western blot, ELISA, and bioactivity assays.

Essential context and supporting details:

• Surface Plasmon Resonance (SPR): Used to study protein-protein interactions, particularly the binding of IL-1 RII to its ligands and its role as a decoy receptor for IL-1.
• In Vivo Studies: Recombinant soluble IL-1 RII has been applied in animal models to investigate its inhibitory effects on ectopic endometrial tissue implantation and growth, suggesting therapeutic potential for conditions such as endometriosis.
• Antibody Absorption: Utilized to absorb specific antibodies in immunological assays, aiding in the characterization of IL-1 RII expression and function.
• Western Blot: Employed for the detection and quantification of IL-1 RII protein in cell and tissue lysates, confirming its expression and molecular weight.
• ELISA (Enzyme-Linked Immunosorbent Assay): Used as a standard or analyte to quantify IL-1 RII levels in biological samples, particularly in studies related to cytokine regulation and clinical outcomes following acute ischemic stroke.
• Bioactivity Assays: Validated for assessing the biological activity of IL-1 RII, including its ability to antagonize IL-1 signaling and inhibit downstream inflammatory responses.

Additional relevant information:

• Decoy Function: Both membrane-bound and soluble forms of IL-1 RII act as decoy receptors, inhibiting IL-1 activity by preventing its interaction with the signaling type I receptor complex.
• Research Areas: Applications span immunology (B cell development, allergy, asthma), angiogenesis, and cytokine signaling studies.
• Sample Types: Validated in both in vitro and in vivo experimental systems.

These validated applications make recombinant human IL-1 RII a versatile tool for studying cytokine biology, immune regulation, and potential therapeutic interventions.

To reconstitute and prepare Recombinant Human IL-1 RII protein for cell culture experiments, dissolve the lyophilized protein at a concentration of 250 μg/mL in sterile PBS containing at least 0.1% human or bovine serum albumin (BSA). This carrier protein helps stabilize the recombinant protein and prevents adsorption to surfaces.

Step-by-step protocol:

• Check the vial label for the recommended reconstitution volume, as this may vary by batch or supplier.
• Add sterile PBS with 0.1% BSA to the vial to reach the desired concentration (e.g., 250 μg/mL).
• Gently agitate the vial at room temperature for 15–30 minutes to fully dissolve the protein. Avoid vigorous shaking or vortexing, as this can cause foaming and denaturation.
• Aliquot the solution into sterile tubes to avoid repeated freeze-thaw cycles, which can degrade the protein.
• Store aliquots at ≤ –20 °C for long-term storage. For short-term use, keep at 4 °C and use within one week.
• Before use in cell culture, dilute the stock solution to the working concentration in cell culture medium or buffer containing carrier protein (e.g., BSA or FCS) to maintain stability.

Additional notes:

• Always use sterile technique to prevent contamination.
• If the protein is shipped at ambient temperature, store it immediately at the recommended temperature upon receipt.
• Avoid concentrations above 1 mg/mL during reconstitution to prevent aggregation.
• If the product datasheet recommends a different buffer or concentration, follow those instructions for optimal activity.

This protocol ensures the recombinant IL-1 RII protein remains stable and active for cell culture applications.