Recombinant Mouse IL-1 RII

Recombinant mouse IL-1 RII serves as a potent antagonist of IL-1 signaling and offers several compelling advantages for research applications studying interleukin-1 biology and inflammation.

Mechanism of Action and Functional Properties

IL-1 RII functions as a decoy receptor that effectively blocks IL-1 activity by preventing ligand binding to the signaling type I receptor complex. Unlike the type I receptor, which has a long cytoplasmic domain capable of transducing IL-1 signals, the type II receptor possesses a short cytoplasmic domain and does not directly transduce IL-1 signals. This structural difference makes it an ideal tool for selectively inhibiting IL-1-mediated responses without triggering downstream signaling cascades.

The recombinant form demonstrates potent antagonistic activity, with concentrations of 3-30 μg/mL capable of inhibiting approximately 50% of the biological response induced by 50 pg/mL of recombinant mouse IL-1 alpha. This dose-dependent inhibition allows for precise experimental control and titration in your research.

Research Applications

Inflammatory Disease Models

IL-1 RII is particularly valuable for investigating IL-1-mediated inflammation in murine models. The receptor's role in controlling proinflammatory states makes it useful for studying conditions where IL-1 dysregulation contributes to pathology. Research demonstrates that IL-1Ra deficiency leads to spontaneous autoimmune diseases in mice, underscoring the importance of IL-1 antagonism in maintaining immune homeostasis.

Gene Regulation Studies

Recombinant IL-1 RII enables investigation of IL-1-mediated gene regulation in murine inflammation models. By blocking IL-1 signaling, you can identify genes and pathways specifically dependent on IL-1 activity versus those regulated through alternative mechanisms.

Mechanistic Research

The receptor's decoy function allows you to dissect IL-1 biology by selectively removing IL-1 signaling while maintaining other cytokine pathways intact. This specificity is particularly valuable when studying complex immune responses where multiple cytokines contribute to the overall phenotype.

Recombinant Mouse IL-1 RII should not be used as a standard for quantification or calibration in ELISA assays designed to measure IL-1β or other cytokines; it is only appropriate as a standard in assays specifically designed to quantify IL-1 RII itself.

Key context and supporting details:

• ELISA standards must match the analyte: For accurate quantification, the standard used in an ELISA must be the same molecule as the target analyte. For example, ELISAs for mouse IL-1β use recombinant mouse IL-1β as the standard, not its receptor or other related proteins.
• IL-1 RII is a receptor, not the cytokine: IL-1 RII (Interleukin-1 receptor type II) is a decoy receptor for IL-1β and IL-1α, not the cytokine itself. Its structure and immunoreactivity are distinct from IL-1β, so it will not generate a standard curve that is relevant for IL-1β quantification.
• ELISA kits are analyte-specific: Commercial ELISA kits for IL-1β are calibrated with recombinant IL-1β, and their antibodies are specific to IL-1β. Similarly, ELISA kits for IL-1 RII use recombinant IL-1 RII as the standard and are validated for that analyte. Using the wrong standard will result in inaccurate and non-interpretable data.
• Cross-reactivity is minimal: ELISA kits are tested for cross-reactivity and interference. IL-1 RII does not cross-react in IL-1β assays, and vice versa.

Best practice:

• Use recombinant mouse IL-1β as a standard for IL-1β ELISA assays.
• Use recombinant mouse IL-1 RII only as a standard in ELISA assays specifically designed to quantify IL-1 RII.

If your goal is to quantify IL-1 RII (not IL-1β or other cytokines), then recombinant mouse IL-1 RII is appropriate as a standard, but only in an assay validated for IL-1 RII detection. If you are quantifying IL-1β or another cytokine, you must use the corresponding recombinant cytokine as the standard.

Recombinant Mouse IL-1 RII has been validated for several applications in published research, primarily related to its role as a decoy receptor for IL-1 and its use in modulating inflammatory responses. Key applications include:

• Cell Culture Assays: Recombinant Mouse IL-1 RII is used in cell culture to inhibit IL-1 signaling, thereby studying the effects of IL-1 blockade on cellular responses such as proliferation, activation, and cytokine production. It is particularly useful in experiments where IL-1 activity needs to be neutralized or modulated.

• ELISA (Standard): The protein has been used as a standard in ELISA assays to quantify IL-1 levels or to study IL-1 binding and inhibition.

• Inhibition of IL-1 Biological Responses: Studies have demonstrated that recombinant Mouse IL-1 RII can inhibit IL-1-induced biological responses, such as cytokine production and cell activation, by acting as a decoy receptor that sequesters IL-1 and prevents its interaction with the signaling IL-1 receptor type I (IL-1RI).

• In Vivo and Ex Vivo Models: The protein has been used in animal models to study the effects of IL-1 blockade on inflammation, immune responses, and disease progression. For example, it has been used to investigate the role of IL-1 in conditions such as type 2 diabetes, where IL-1 signaling is implicated in cytokine resistance and macrophage dysfunction.

• Research on Cytokine Regulation: Recombinant Mouse IL-1 RII is employed in studies focused on the regulation of cytokine networks, particularly in the context of inflammation, immune cell activation, and the control of proinflammatory states.

These applications highlight the utility of Recombinant Mouse IL-1 RII in both basic research and translational studies aimed at understanding and modulating IL-1-mediated inflammatory processes.

To reconstitute and prepare Recombinant Mouse IL-1 RII protein for cell culture experiments, follow these steps based on best practices for recombinant cytokines and specific guidance for IL-1 RII:

1. Centrifuge the vial briefly before opening to ensure all lyophilized material is at the bottom.

2. Reconstitution:

   • Use sterile phosphate-buffered saline (PBS) as the diluent, as most IL-1 RII preparations are lyophilized from PBS and recommend reconstitution in the same buffer.
   • For typical working concentrations, reconstitute to 500 μg/mL in sterile PBS. If your experimental protocol requires a different concentration, adjust the volume accordingly.
   • If the protein is particularly dilute or prone to adsorption, add 0.1% carrier protein (such as heat-inactivated fetal calf serum (FCS) or tissue culture-grade bovine serum albumin (BSA)) to the buffer to stabilize the protein and minimize loss due to adsorption.

3. Mix gently:

   • Allow the vial to sit at room temperature for 15–30 minutes with gentle agitation to fully dissolve the protein. Avoid vigorous shaking or vortexing, which can cause foaming or denaturation.

4. Aliquot and storage:

   • After reconstitution, aliquot the solution into single-use volumes to avoid repeated freeze-thaw cycles, which can degrade the protein.
   • Store aliquots at –20°C to –70°C for long-term storage (up to 3 months), or at 2–8°C for short-term use (up to 1 month), under sterile conditions.
   • Avoid repeated freeze-thaw cycles by using aliquots.

5. Preparation for cell culture:

   • Before adding to cell cultures, dilute the reconstituted stock to the desired working concentration using cell culture medium or PBS containing 0.1% carrier protein.
   • Ensure all solutions are sterile and endotoxin levels are appropriate for cell culture applications.

Summary Table: Recombinant Mouse IL-1 RII Reconstitution

Additional notes:

• Always consult the specific product datasheet for any unique instructions, as formulations may vary.
• If the protein is supplied with a carrier protein already present, additional carrier may not be necessary.
• Confirm protein concentration after reconstitution if precise dosing is critical.

These steps will ensure the recombinant protein is properly prepared for reliable and reproducible cell culture experiments.