Recombinant Human IL-13

Recombinant human IL-13 is a valuable tool for research applications due to its diverse immunoregulatory functions and well-characterized biological activities. Here are the key reasons to incorporate it into your research:

Immunomodulatory Functions

IL-13 is a T-helper type 2 cytokine with potent effects on multiple immune cell populations. It modulates the behavior of monocytes, macrophages, and B cells by inducing increased MHC class II expression while simultaneously inhibiting the production of pro-inflammatory cytokines such as TNF-α and IL-1β. This dual capacity makes it particularly useful for studying immune tolerance and anti-inflammatory mechanisms.

Cellular Activation and Differentiation

The protein stimulates proliferation in various cell types and promotes B cell activation, immunoglobulin class switching to IgE, and upregulation of CD23/Fc epsilon RII. IL-13 also induces differentiation of human monocytes, enhances their survival in culture, and promotes differentiation, proliferation, and isotype switching in B cells. These properties make it ideal for investigating lymphocyte development and antibody responses.

Macrophage Polarization and Activity Modulation

IL-13 down-modulates macrophage activity by reducing the production of pro-inflammatory mediators in response to interferon-gamma or bacterial lipopolysaccharides. It enhances production of the IL-1 receptor antagonist IL-1ra and decreases nitric oxide production by activated macrophages. This makes it valuable for studying alternative macrophage activation and tissue repair mechanisms.

Broad Receptor Distribution

IL-13 receptors are expressed on a wide range of cell types including B cells, basophils, eosinophils, mast cells, endothelial cells, fibroblasts, monocytes, macrophages, respiratory epithelial cells, and smooth muscle cells. This extensive distribution enables investigation of IL-13 signaling across diverse biological systems and disease models.

Disease-Relevant Applications

IL-13 plays critical roles in allergic inflammation, asthma pathogenesis, parasite immunity, tissue remodeling, and tumor biology. The protein regulates gastrointestinal parasite expulsion, airway hyperresponsiveness, and immune cell inflammation in response to pathophysiological changes. These applications make it particularly relevant for studying allergic diseases, parasitic infections, and cancer immunology.

Signal Transduction Pathway

IL-13 exerts its biological effects through a receptor complex comprising the IL-4R chain and IL-13RA1 chain, activating JAK1 and TYK2 kinases and leading to STAT6 activation. This well-defined signaling cascade allows for mechanistic studies of cytokine-mediated immune responses and downstream transcriptional regulation.

Yes, recombinant human IL-13 can be used as a standard for quantification or calibration in ELISA assays, provided it is properly validated and matched to your assay system. Recombinant IL-13 is commonly employed as a standard in sandwich ELISA protocols to generate calibration curves for quantifying IL-13 concentrations in biological samples.

Key considerations for use:

• Purity and Formulation: The recombinant IL-13 should be of high purity and preferably formulated in a buffer compatible with your ELISA system. Some formulations include carrier proteins (e.g., BSA) to enhance stability, which may be beneficial for standard preparation.
• Validation: It is essential to validate the recombinant standard in your specific ELISA setup. This includes confirming parallelism between the standard curve and endogenous IL-13 in your sample matrix, as well as assessing recovery, accuracy, and precision.
• Standard Curve Preparation: Prepare a serial dilution of the recombinant IL-13 to cover the expected concentration range in your samples. Run the standard curve in duplicate or triplicate for reliability.
• Matrix Effects: If your samples are in complex matrices (e.g., serum, plasma), ensure that the recombinant standard behaves similarly to endogenous IL-13. Spike-recovery experiments and parallelism studies are recommended to confirm assay validity.
• Reference Calibration: Some ELISA kits calibrate their standards against international reference materials (e.g., NIBSC 94/622), which can improve quantification accuracy. If available, calibrate your recombinant standard accordingly.

Protocol best practices:

• Always run standards and samples in duplicate or triplicate to ensure reproducibility.
• Include quality controls at multiple concentrations to monitor assay performance.
• Store recombinant IL-13 aliquots at recommended temperatures to maintain stability.

Summary Table: Recombinant Human IL-13 as ELISA Standard

In conclusion, recombinant human IL-13 is suitable for use as a standard in ELISA quantification, provided it is validated for your assay conditions and sample types.

Recombinant Human IL-13 has been validated for a range of applications in published research, primarily in bioassays and cell culture experiments involving human cells. These applications span immunology, oncology, fibrosis, and metabolic research.

Key validated applications include:

• Bioassays:

  • Used to assess macrophage polarization (e.g., induction of M2 phenotype in THP-1-derived macrophages).
  • Studied for its role in fibrosis (e.g., pulmonary fibrosis models via M2 macrophage activation).
  • Investigated in cancer biology, such as cholangiocarcinoma progression, lung adenocarcinoma, and gastric metaplasia.
  • Used to probe immune cell signaling and cytokine interactions, including effects on monocytes, macrophages, and B cells.
  • Employed in studies of adipose tissue inflammation and metabolic regulation.

• Cell Culture:

  • Applied to primary cells and cell lines to study direct effects on epithelial cells, fibroblasts, and immune cells.
  • Used to model allergic inflammation, airway hyperresponsiveness, and tissue remodeling.
  • Validated for proliferation assays in cancer cell lines, such as angiosarcoma and glioblastoma.

• Functional Studies:

  • Demonstrated to modulate MHC class II expression and inhibit inflammatory cytokine production (e.g., TNF-α, IL-1β) in monocytes/macrophages.
  • Used in in vivo models (e.g., NOD mouse for diabetes protection).
  • Studied in the context of IL-13 receptor signaling and as a target for immunotherapy (e.g., IL-13Rα2-directed CAR T cells, immunotoxins, and vaccines in cancer models).

• Other Research Areas:

  • Asthma and allergy models: IL-13 is a key mediator in these conditions, and recombinant protein is used to mimic or block its effects in vitro and in vivo.
  • Tissue fibrosis: Used to induce or study fibrotic responses in various tissues.
  • Metabolic studies: Investigated for its role in adipose tissue biology and insulin resistance.

Summary Table of Validated Applications

In summary: Recombinant Human IL-13 is widely validated for use in bioassays and cell culture to study immune modulation, fibrosis, cancer biology, and metabolic regulation, as well as in preclinical models of disease and immunotherapy research.

To reconstitute and prepare Recombinant Human IL-13 protein for cell culture experiments, dissolve the lyophilized protein at a concentration of 100 μg/mL in sterile PBS containing at least 0.1% human or bovine serum albumin (BSA) if the formulation includes BSA as a carrier; if carrier-free, use sterile PBS alone.

Essential steps and considerations:

• Centrifuge the vial briefly before opening to ensure all material is at the bottom.
• Add the recommended volume of sterile buffer (PBS or 10 mM HCl, depending on the specific formulation; always check the product datasheet for buffer requirements).
• Gently mix by pipetting up and down; do not vortex, as vigorous mixing can denature the protein.
• Allow the protein to dissolve completely (typically 5–10 minutes at room temperature).
• Aliquot the stock solution to avoid repeated freeze-thaw cycles, which can degrade cytokine activity.
• Store aliquots at −20 °C to −70 °C for long-term storage, or at 2–8 °C for short-term use (up to 1 month under sterile conditions).
• For cell culture experiments, dilute the stock solution to the desired working concentration in cell culture medium immediately before use. Typical working concentrations for bioassays range from 0.5–2.5 ng/mL, but optimal dosing should be determined empirically for your specific cell type and assay.

Additional notes:

• If the protein is supplied in an acidic buffer (e.g., 10 mM HCl or sodium citrate), after initial reconstitution, further dilute in PBS or cell culture medium to neutralize before adding to cells.
• Always use sterile technique to prevent contamination.
• If the protein is carrier-free, consider adding BSA (0.1%) to working solutions to stabilize the protein, especially for low-concentration applications.
• Avoid repeated freeze-thaw cycles by aliquoting into single-use volumes.

Summary Table:

Always consult the specific product datasheet for formulation and buffer requirements, as these may vary between preparations.