Recombinant Human IL-4

Recombinant human IL-4 is a versatile and powerful tool for immunological research with multiple compelling applications across diverse experimental systems.

Immune Cell Differentiation and Activation

Recombinant IL-4 serves as a critical cytokine for directing immune cell development and function. It promotes the differentiation of naïve CD4+ T cells into Th2-polarized cells, a fundamental process in adaptive immunity research. The protein is particularly valuable for B cell studies, where it drives cell proliferation and survival while promoting immunoglobulin class switching to IgG4 and IgE. Additionally, IL-4 primes and enhances chemotaxis of mast cells, eosinophils, and basophils, making it essential for studying type 2 immune responses.

Dendritic Cell Generation

One of the most significant applications involves generating dendritic cells from induced pluripotent stem cells. When combined with other growth factors, recombinant IL-4 facilitates the transformation of pluripotent stem cells into dendritic cells in high numbers. These engineered dendritic cells have substantial value for disease modeling, therapeutic screening, and cell-based therapies, representing a powerful platform for translational research.

Cancer Immunotherapy Research

Recent advances demonstrate that IL-4-based approaches enhance anti-tumor immunity. Fc-fused IL-4 constructs revitalize exhausted CD8+ T cells through STAT6 and mTOR signaling pathways, augmenting glycolytic metabolism and NAD concentration. This enhancement synergizes effectively with adoptive cell transfer and immune checkpoint blockade therapies, producing durable tumor remission across multiple preclinical models. Furthermore, IL-4 suppression has been studied as a therapeutic strategy to enhance tumor-specific T lymphocyte activity and improve anti-tumor immunotherapy efficacy.

Functional Assays and Bioassays

Recombinant IL-4 is optimized for functional assays and differentiation studies in cell culture systems. It serves as a standard for IL-4 detection and quantification assays, and enables screening of antibodies that block IL-4 signaling or engineered IL-4 variants.

Parasitic and Allergic Response Studies

IL-4 is the key cytokine controlling immune responses to extracellular parasites and helminth infections. Conversely, dysregulated IL-4 expression contributes to Th2-mediated pathologies including asthma and atopic dermatitis, making it essential for studying allergic mechanisms and developing therapeutic interventions.

The broad applicability of recombinant human IL-4 across immunological, translational, and disease-modeling research makes it an indispensable reagent for contemporary life sciences research.

Recombinant human IL-4 can be used as a standard for quantification or calibration in ELISA assays, provided it is properly validated for your specific assay system. This is a common and accepted practice in cytokine quantification.

Supporting details and best practices:

• Recombinant IL-4 is widely used as an ELISA standard: Multiple ELISA kits and protocols specify the use of recombinant human IL-4 as the standard for generating calibration curves, enabling quantification of IL-4 in biological samples. These standards are typically supplied lyophilized and reconstituted to prepare serial dilutions for the standard curve.

• Assay compatibility: Most commercial ELISA kits for human IL-4 are validated to recognize both recombinant and natural forms of IL-4, and dose-response curves for natural and recombinant IL-4 are reported to be parallel, indicating comparable immunoreactivity. This ensures that quantification using recombinant IL-4 as a standard is accurate for both recombinant and endogenous IL-4.

• Standard preparation: For accurate quantification, prepare a fresh standard curve with each assay using serial dilutions of the recombinant IL-4 standard, following the protocol provided with your ELISA kit or validated in your laboratory. Ensure the recombinant IL-4 is reconstituted and diluted in the same buffer or matrix as your samples to minimize matrix effects.

• Carrier protein considerations: Recombinant IL-4 is often supplied with a carrier protein (such as BSA) to enhance stability and prevent adsorption to plasticware. If your application is sensitive to carrier proteins, carrier-free formulations are also available.

• Validation: If you are using a recombinant IL-4 standard from a source different than your ELISA kit, or developing your own assay, validate that the standard curve is linear and parallel to curves generated with natural IL-4, and that recovery and precision meet your assay requirements.

• Documentation: Refer to your ELISA kit’s documentation or published protocols for specific instructions regarding standard preparation and validation, as minor differences in protein folding, glycosylation, or formulation can affect assay performance.

Summary Table: Use of Recombinant Human IL-4 as ELISA Standard

In conclusion: Recombinant human IL-4 is suitable and commonly used as a standard for ELISA quantification, but always confirm compatibility and validate performance within your specific assay context.

Recombinant Human IL-4 has been validated for a broad range of applications in published research, primarily in bioassays, cell culture, immune cell differentiation, and functional studies involving human cells.

Key validated applications include:

• Bioassays: Used to assess biological activity, such as proliferation, survival, and differentiation of immune cells (e.g., T cells, B cells, mast cells, eosinophils, basophils).
• Cell Culture: Applied to stimulate or differentiate immune cells, including the induction of Th2 phenotype in naïve CD4+ T cells and the activation of B cells.
• T Cell Differentiation: Drives Th2 differentiation, a critical process in allergy and asthma research.
• B Cell Activation and Class Switching: Promotes immunoglobulin class switch to IgG4 and IgE in human B cells.
• Dendritic Cell and Macrophage Studies: Used to polarize macrophages and activate dendritic cells in tumor immunology and inflammation models.
• Screening Assays: Serves as a standard for ELISA, detection, and quantification assays, as well as for screening inhibitors or engineered IL-4 variants.
• Tumor Microenvironment and Immunotherapy Research: Validated in studies investigating modulation of the tumor microenvironment, immune checkpoint blockade, and adoptive cell transfer therapies.
• Neuroscience: Demonstrated to activate human sensory neurons, implicating a role in neuroimmune signaling and itch.
• Therapeutic Development: Used in preclinical models for autoimmune diseases, cancer, and allergic conditions.

Representative published research applications:

• Tumor-associated macrophage modeling in glioblastoma.
• Th2 immune response studies in liver disease.
• Chemotherapy efficacy enhancement in Ewing sarcoma.
• Immune checkpoint blockade response modulation.
• Dendritic cell activation for systemic T-cell immunity.
• Suppression of Th2 cytokine production in asthma models.
• Phase I clinical studies in advanced cancer patients.

Summary Table of Validated Applications

These applications are supported by both primary research articles and product validation data from multiple independent sources.

Reconstitution Procedures

Recombinant human IL-4 is typically supplied as a lyophilized powder that requires reconstitution before use in cell culture experiments. The reconstitution process is critical for maintaining protein activity and stability.

Initial Preparation Steps

Before opening the vial, centrifuge it for 20-30 seconds in a microcentrifuge to collect any protein material that may be lodged in the cap or on the vial walls. This ensures complete recovery of the product. Work under sterile conditions throughout the entire process to prevent contamination.

Thaw the vial at room temperature and disinfect the rubber plug surface with an appropriate disinfectant before use.

Reconstitution Media Options

The choice of reconstitution medium depends on your specific application and whether you require a carrier-free preparation:

Standard reconstitution involves dissolving the lyophilized protein in sterile water or sterile phosphate-buffered saline (PBS). For carrier-containing formulations, reconstitute at 100-200 μg/mL in sterile PBS containing at least 0.1% human or bovine serum albumin (BSA). Alternatively, stock solutions should be prepared at no less than 10 μg/mL in sterile buffer containing carrier protein such as 1% BSA, human serum albumin (HSA), or 10% fetal bovine serum (FBS).

For carrier-free preparations, reconstitute at 100-200 μg/mL in sterile PBS without additional carrier proteins.

Mixing Technique

Avoid vigorous mixing methods. Do not shake or vortex the vial, as this can cause foam formation and protein denaturation. Instead, gently mix the solution by carefully swaying the vial until all visible components are dissolved, which typically takes less than one minute. After reconstitution, gently mix the vial to ensure homogeneity.

Storage and Stability

Short-term Storage

Reconstituted IL-4 can be stored at 2-8°C for up to 1 week under sterile conditions. For extended storage at refrigeration temperatures, further dilute the protein in a buffer containing 0.1% BSA.

Long-term Storage

For long-term storage, maintain reconstituted IL-4 at -20°C in undiluted aliquots for up to six months. Alternatively, storage at -20 to -70°C can extend stability to three months. The lyophilized material itself is stable for greater than six months at -20 to -70°C.

Critical consideration: Use a manual defrost freezer and avoid repeated freeze-thaw cycles, as these can compromise protein activity and stability.

Practical Considerations for Cell Culture

When preparing IL-4 for cell culture experiments, aliquot the reconstituted protein into smaller portions to minimize freeze-thaw cycles. Use aliquots as soon as possible after reconstitution for optimal biological activity. The protein can be further diluted into other buffered solutions as needed for your specific experimental protocol.

For bioassay applications, recombinant human IL-4 induces proliferation of target cells in a dose-dependent manner, so prepare serial dilutions according to your experimental design requirements.