Recombinant Human Interleukin 13 Receptor, Alpha 1 (IL-13 Rα1)

Recombinant Human Interleukin 13 Receptor, Alpha 1 (IL-13 Rα1) is a critical tool for research focused on cytokine signaling, immune modulation, and disease mechanisms involving the IL-13/IL-4 pathway. Its use is particularly relevant in studies of asthma, allergy, fibrosis, and alternative macrophage activation.

Key reasons to use recombinant IL-13 Rα1 in research applications:

• Dissecting IL-13/IL-4 Signaling Pathways: IL-13 Rα1 is a core component of the type II IL-4 receptor complex, which mediates signaling for both IL-13 and IL-4. Using recombinant IL-13 Rα1 allows you to study ligand-receptor interactions, downstream signaling events (such as JAK/STAT activation), and the specific contributions of this receptor in various cell types, including airway epithelial cells, fibroblasts, smooth muscle, and most leukocytes except T lymphocytes.

• Modeling Disease Mechanisms: IL-13 Rα1 is essential for mediating the effects of IL-13 in models of asthma, allergy, and fibrosis. Recombinant IL-13 Rα1 can be used to:

  • Investigate how IL-13 drives airway hyperresponsiveness, mucus production, and tissue remodeling.
  • Study the receptor’s role in alternative macrophage activation (M2 polarization), which is important in tissue repair and fibrosis.
  • Explore the inhibition of classical macrophage activation by IL-13, which is relevant for immune regulation and chronic inflammation.

• Screening and Characterizing Therapeutics: Recombinant IL-13 Rα1 is valuable for:

  • Screening antibodies or small molecules that block IL-13/IL-13 Rα1 interactions, which is a therapeutic strategy for asthma, atopic dermatitis, and other inflammatory diseases.
  • Developing and validating ELISA or other binding assays to quantify IL-13 or test the efficacy of IL-13 antagonists.

• Functional and Structural Studies: Recombinant IL-13 Rα1 enables:

  • Biochemical and biophysical analyses (e.g., surface plasmon resonance, crystallography) to characterize binding affinities and receptor-ligand complex structures.
  • Cell-based assays to assess downstream gene expression, receptor activation, and cellular responses to IL-13 or IL-4 stimulation.

• Genetic and Variant Analysis: Recombinant forms can be engineered to represent specific genetic variants, allowing the study of how polymorphisms in IL-13 Rα1 affect signaling and disease susceptibility.

Summary of Applications:

• Mechanistic studies of cytokine signaling (IL-13/IL-4 pathways)
• Disease modeling (asthma, allergy, fibrosis)
• Therapeutic screening (antagonists, antibodies)
• Assay development (ELISA, binding assays)
• Structural and biophysical characterization
• Functional genomics and variant analysis

Using recombinant IL-13 Rα1 provides a controlled, reproducible system to dissect the molecular and cellular roles of this receptor in health and disease, supporting both basic research and translational applications.

Recombinant Human Interleukin 13 Receptor, Alpha 1 (IL-13 Rα1) can be used as a standard for quantification or calibration in ELISA assays, but only for assays specifically designed to measure IL-13 Rα1, not for IL-13 itself.

Key context and details:

• ELISA standards must match the analyte: In ELISA, the standard used for calibration must be the same molecule as the analyte being measured. If your assay is designed to quantify IL-13 Rα1 (the receptor), then recombinant IL-13 Rα1 is appropriate as a standard. If your assay is for IL-13 (the cytokine/ligand), you must use recombinant IL-13 as the standard.

• Assay specificity: Commercial ELISA kits for IL-13 Rα1 use recombinant IL-13 Rα1 as the standard to generate the calibration curve. These kits are validated to detect both natural and recombinant forms of IL-13 Rα1, ensuring accurate quantification of the receptor in biological samples.

• Not interchangeable with IL-13 standards: Recombinant IL-13 Rα1 cannot be used as a standard in ELISAs designed to detect IL-13, as the antibodies in those assays are specific for IL-13, not its receptor. Similarly, recombinant IL-13 cannot be used as a standard in IL-13 Rα1 assays.

• Validation and calibration: For accurate quantification, the recombinant IL-13 Rα1 standard should be well-characterized and ideally calibrated against an international reference standard if available. The standard curve should cover the expected concentration range of IL-13 Rα1 in your samples.

Summary Table:

Best practices:

• Always use a standard that matches the analyte your ELISA is designed to detect.
• Confirm that your recombinant IL-13 Rα1 is of high purity and properly quantified.
• Validate the standard curve in your specific assay matrix for accuracy and reproducibility.

If you are quantifying IL-13 Rα1, you can use recombinant IL-13 Rα1 as your standard. If you are quantifying IL-13, you must use recombinant IL-13 as your standard. Mixing these will result in inaccurate and non-specific results.

Recombinant Human Interleukin 13 Receptor, Alpha 1 (IL-13Rα1) has been validated in published research for several key applications, primarily in the study of immune cell differentiation, signaling, disease models, and as a potential therapeutic target or biomarker.

Validated Applications in Published Research:

• Surface Marker for Macrophage Subsets:
  IL-13Rα1 is used as a surface marker to distinguish M2 macrophages from M1 macrophages. Its expression is associated with M2 polarization, and it is functionally relevant for STAT6 signaling and phagocytic activity assays in both in vitro and in vivo models.

• Functional Signaling Studies:
  Recombinant IL-13Rα1 is used to reconstitute or block IL-13/IL-4 signaling pathways in cell-based assays, particularly to study the activation of the JAK/STAT6 pathway and the induction of alternatively activated (M2) macrophages. It is also used to dissect the requirements for receptor subunits in cytokine signaling using knockout or overexpression systems.

• Gene Expression and Pathway Analysis:
  IL-13Rα1 is employed in gene expression studies to assess the induction of IL-4/IL-13-responsive genes and to analyze downstream effects on immune modulation, such as inhibition of IFN-γ-induced classical macrophage activation.

• Disease Model Research:
  The receptor is validated in animal models of fibrosis, heart disease, and lung injury to study its role in tissue remodeling, repair, and inflammation. For example, IL-13Rα1 has been shown to regulate myocardial homeostasis and is implicated in the pathogenesis of heart failure and pulmonary fibrosis.

• Cancer Research and Biomarker Studies:
  IL-13Rα1 expression is analyzed in hematological malignancies (e.g., Hodgkin lymphoma) as a potential biomarker for disease aggressiveness and therapeutic response. It is also being explored as a therapeutic target in diffuse intrinsic pontine glioma (DIPG) and other cancers.

• Metabolic and Adipogenesis Studies:
  IL-13Rα1 signaling has been validated in preadipocyte models to study its role in beige adipogenesis and metabolic programming.

Experimental Techniques Where Recombinant IL-13Rα1 Is Used:

• Flow cytometry and immunophenotyping (as a cell surface marker)
• Functional cell signaling assays (e.g., STAT6 phosphorylation)
• Gene expression analysis (qPCR, RNA-seq)
• In vitro and in vivo phagocytosis assays
• Animal models of disease (fibrosis, heart failure, lung injury)
• Immunohistochemistry and tissue staining (biomarker studies)

Summary Table: Key Validated Applications

These applications are supported by peer-reviewed studies using recombinant IL-13Rα1 in both basic and translational research contexts.

To reconstitute and prepare Recombinant Human Interleukin 13 Receptor, Alpha 1 (IL-13 Rα1) protein for cell culture experiments, dissolve the lyophilized protein in 10 mM PBS (pH 7.4) to achieve a final concentration between 0.1–1.0 mg/mL. This buffer is compatible with most cell culture applications and maintains protein stability.

Step-by-step protocol:

• Centrifuge the vial briefly before opening to ensure all lyophilized material is at the bottom.
• Add sterile 10 mM PBS (pH 7.4) to the vial. For example, to prepare 1 mg/mL, add 100 μL PBS to 100 μg protein; for 0.1 mg/mL, add 1 mL PBS to 100 μg protein.
• Gently mix by pipetting up and down or by slow vortexing. Avoid vigorous agitation to prevent protein denaturation.
• Allow the protein to dissolve completely at room temperature for 10–30 minutes. Inspect visually to confirm full dissolution.
• Aliquot the solution to avoid repeated freeze-thaw cycles, which can degrade the protein.
• Store aliquots at −20°C or −80°C for long-term storage. For short-term use (up to 1 month), store at 4°C.

Additional considerations:

• If your application is sensitive to endotoxin, confirm the endotoxin level is suitable for cell culture (typically <1 EU/μg).
• For functional assays, you may further dilute the reconstituted stock in cell culture medium or assay buffer as needed.
• Avoid buffers containing carrier proteins (e.g., BSA or serum) unless specifically required for your assay, as these can interfere with downstream applications.
• Always consult the product-specific Certificate of Analysis (CoA) for any manufacturer-recommended variations in reconstitution protocol.

Summary Table:

This protocol ensures optimal solubility and stability of IL-13 Rα1 for cell culture experiments.