Recombinant Human IL-18 Receptor Alpha (IL-18 Rα) serves as a critical component for studying IL-18 signaling and immune responses in research applications. Here are the key reasons to incorporate this protein into your research:

Functional Significance in IL-18 Signaling

IL-18 Rα forms the essential ligand-binding component of the high-affinity IL-18 receptor complex. When IL-18 engages with IL-18 Rα and its associated IL-18 Rβ chain, this interaction initiates a signaling cascade that recruits intracellular adaptor proteins including MyD88, IRAK1/4, and TRAF6, ultimately activating mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) pathways. This makes IL-18 Rα indispensable for investigating the molecular mechanisms underlying IL-18-mediated immune activation.

Immune Response Characterization

Signaling through the IL-18 receptor promotes Th1-biased immune responses and enhances natural killer (NK) cell cytolytic activity. By utilizing recombinant IL-18 Rα in your experimental systems, you can model and measure:

• IL-18-induced interferon-gamma (IFN-γ) production by T cells and NK cells
• Enhancement of NK cell cytotoxic functions
• Differentiation of CD4+ T cells into helper effector cells
• Synergistic effects when IL-18 signaling is combined with IL-12

Therapeutic Research Applications

IL-18 Rα is particularly valuable for cancer immunotherapy research. The receptor's role in promoting antitumor immune responses makes it essential for studying:

• Antibody-dependent cellular cytotoxicity (ADCC) mechanisms
• Combination immunotherapy approaches with monoclonal antibodies
• Immune cell infiltration into tumor microenvironments
• Cytokine production profiles in response to IL-18 stimulation

Technical Advantages

Modern engineered variants of IL-18 and its receptor components maintain biological potency while offering improved stability and manufacturability. When selecting recombinant IL-18 Rα for your research, biotinylated variants with precision tagging provide uniform protein orientation on surfaces, ensuring consistent bioactivity and reliable experimental results without interference from protein immobilization artifacts.

Recombinant Human IL-18 Rα (IL-18 receptor alpha) is generally not suitable as a standard for quantification or calibration in ELISA assays designed to measure IL-18 or its binding proteins. ELISA standards must match the analyte being quantified—in this case, IL-18 or IL-18BP—not the receptor.

Key points:

• ELISA standards are typically recombinant forms of the analyte you wish to measure (e.g., IL-18 or IL-18BP), not the receptor (IL-18Rα).
• Recombinant IL-18 Rα is a receptor protein, not the cytokine IL-18 itself. Using it as a standard would not provide accurate quantification of IL-18, as the antibodies in the ELISA are specific to IL-18 or IL-18BP, not the receptor.
• Commercial ELISA kits for IL-18 quantification use recombinant IL-18 (often E. coli-expressed) as the standard, and these standards are validated to ensure parallelism with natural IL-18 in biological samples.
• Carrier-free or BSA-containing forms of recombinant proteins are chosen based on application, but the critical factor is that the standard must be the same molecule as the analyte being measured.

If your goal is to quantify IL-18 Rα itself (for example, soluble IL-18Rα in biological fluids), you would need an ELISA specifically designed for IL-18Rα, and the standard should be recombinant IL-18Rα validated for that assay. For quantifying IL-18 or IL-18BP, use the corresponding recombinant cytokine or binding protein as the standard.

In summary:
Do not use recombinant human IL-18 Rα as a standard for quantifying IL-18 or IL-18BP in ELISA assays. Use a recombinant standard that matches the analyte you are measuring, as validated by the assay protocol.

Applications of Recombinant Human IL-18 Rα in Published Research

Recombinant human IL-18 receptor alpha (IL-18Rα) has been validated for several important applications in published research, primarily focused on immunological and therapeutic contexts.

Biomarker and Diagnostic Applications

Soluble IL-18 receptor complex has been established as a novel biomarker in rheumatoid arthritis, with validation through ELISA-based standard assays. This application demonstrates the utility of IL-18R components in disease diagnosis and monitoring.

Immunological Research Applications

IL-18Rα plays a critical role in studies examining immune cell activation and function. The receptor is essential for IL-18 responsiveness, as co-expression of both IL-18Rα and IL-18Rβ is required for high-affinity binding and proper signaling. This has made IL-18Rα a key target for research involving:

• T cell and NK cell studies: IL-18Rα upregulation on naïve T cells following IL-12 stimulation renders these cells susceptible to IL-18 signaling, making it valuable for investigating T cell priming and activation
• Cytokine-induced memory-like NK cell generation: Research has utilized IL-18R signaling to develop enhanced NK cells with improved anticancer functionality
• CAR-T cell optimization: Studies have examined IL-18R engagement in HER2-CAR T cells to improve anti-tumor functions and increase central memory T cell populations in cellular products

Therapeutic Development Applications

IL-18Rα has been validated as a target for engineered IL-18 variants designed for cancer immunotherapy. Engineered disulfide-stabilized IL-18 Fc-fusion proteins maintain their interactions with IL-18Rα while demonstrating improved stability, extended half-life, and enhanced manufacturability, with demonstrated efficacy in preclinical cancer models.

To reconstitute and prepare Recombinant Human IL-18 Rα protein for cell culture experiments, follow these general best practices based on manufacturer and scientific literature recommendations:

1. Reconstitution

• Centrifuge the vial briefly before opening to ensure all lyophilized powder is at the bottom.
• Reconstitute with sterile PBS or sterile distilled water. Many suppliers recommend reconstituting at 1 mg/mL in sterile PBS (e.g., 0.2 µm filtered PBS).
• Gently mix by swirling or pipetting slowly; avoid vortexing or vigorous pipetting to prevent protein denaturation.
• If the protein is supplied with a carrier protein (e.g., BSA), follow the specific instructions for your product.

2. Preparation for Cell Culture

• Aliquot the reconstituted protein into small, single-use volumes to minimize freeze-thaw cycles.
• Store aliquots at –20°C or –80°C for long-term storage. Avoid repeated freezing and thawing.
• For immediate use, keep the protein on ice.
• Dilute the protein in cell culture medium (e.g., RPMI 1640 with 10% FBS) to the desired working concentration. The optimal concentration should be determined empirically for your specific cell type and assay.

3. Application Notes

• Functional assays may require co-expression or addition of IL-18 Rβ for high-affinity binding and signaling.
• Test for bioactivity using appropriate reporter cells or functional assays to confirm protein activity.

Example Protocol:

1. Briefly centrifuge the vial.
2. Reconstitute with sterile PBS to 1 mg/mL.
3. Gently mix and aliquot.
4. Store at –20°C.
5. For cell culture, dilute to the desired concentration in culture medium.

Always refer to the specific product datasheet for any unique requirements or recommendations.