Recombinant Human IL-3

Recombinant Human IL-3 is widely used in research because it is a potent cytokine that regulates the proliferation, differentiation, and survival of hematopoietic stem and progenitor cells, as well as various mature immune cells. Its applications span basic hematopoiesis studies, immune cell function assays, and disease modeling.

Key reasons to use Recombinant Human IL-3 in research applications:

• Supports hematopoietic stem and progenitor cell culture: IL-3 promotes the proliferation, survival, and differentiation of hematopoietic stem cells (HSCs) and committed progenitors into multiple lineages, including myeloid (basophils, eosinophils, monocytes, granulocytes), erythroid, megakaryocyte, and mast cell lineages.
• Induces colony formation in progenitor assays: IL-3 is commonly used in colony-forming unit (CFU) assays to stimulate the growth of hematopoietic progenitors in semi-solid media, enabling quantification and characterization of progenitor populations.
• Facilitates in vitro differentiation studies: It is used to drive the differentiation of specific cell types from stem or progenitor cells, such as B lymphoid progenitors or dendritic cells, and to study lineage commitment.
• Enhances functional studies of mature immune cells: IL-3 modulates the activity of mature basophils, mast cells, eosinophils, and macrophages, making it valuable for research on allergic inflammation, immune responses to parasites, and cytokine signaling pathways.
• Investigates inflammation and immune regulation: IL-3 is a key orchestrator of inflammation, influencing emergency hematopoiesis, immune cell recruitment, and tissue responses during infection, autoimmune disease, and tissue repair.
• Promotes endothelial and epithelial cell responses: Beyond hematopoietic cells, IL-3 can stimulate proliferation and function of endothelial and epithelial cells, relevant for studies on angiogenesis, tissue regeneration, and inflammation.
• High purity and bioactivity: Recombinant forms are typically >95% pure, endotoxin-tested, and validated in bioassays, ensuring reproducibility and reliability in experimental systems.

In summary, Recombinant Human IL-3 is essential for studies involving hematopoietic cell biology, immune regulation, inflammation, and cell differentiation, and is a standard reagent for both basic and translational research in immunology and hematology.

Yes, recombinant human IL-3 can generally be used as a standard for quantification or calibration in ELISA assays, provided it is of high purity, accurately quantified, and compatible with your assay system. This is a common practice in cytokine ELISA development and quantification.

Key considerations and supporting details:

• Recombinant IL-3 as Standard: Most commercial ELISA kits for human IL-3 use recombinant human IL-3 as the standard to generate the calibration curve. This allows for the quantification of IL-3 in biological samples by comparison to known concentrations of the recombinant protein.

• Assay Compatibility: The recombinant IL-3 standard should be recognized by the capture and detection antibodies used in your ELISA. Most sandwich ELISAs for IL-3 are designed to detect both natural and recombinant forms, including glycosylated and non-glycosylated variants.

• Purity and Quantification: The recombinant IL-3 must be highly purified and its concentration accurately determined, typically by absorbance at 280 nm or amino acid analysis. Carrier-free formulations are preferred for ELISA standards to avoid interference from stabilizing proteins such as BSA, unless your assay specifically requires a carrier.

• Standard Curve Preparation: Prepare a serial dilution of the recombinant IL-3 in the same buffer or matrix as your samples to minimize matrix effects and ensure accurate quantification.

• Validation: It is good practice to validate that your recombinant IL-3 standard produces a dose-response curve parallel to that of endogenous IL-3 in your sample matrix. This ensures that the standard accurately reflects the behavior of native IL-3 in your assay.

• Documentation: Refer to your ELISA kit’s instructions or published protocols to confirm that recombinant IL-3 is suitable as a standard for your specific assay configuration.

Summary Table: Use of Recombinant Human IL-3 as ELISA Standard

Limitations:

• If your ELISA is designed to detect only a specific isoform or post-translational modification of IL-3, ensure your recombinant standard matches this form.
• Always check the manufacturer’s recommendations for your specific ELISA kit, as some kits may require a specific standard formulation.

Conclusion:
Recombinant human IL-3 is widely accepted and used as a standard for quantification in ELISA assays, provided it meets the above criteria and is validated for your assay system.

Recombinant Human IL-3 has been validated for a broad range of applications in published research, primarily in the fields of hematopoiesis, immunology, oncology, and stem cell biology.

Key validated applications include:

• Hematopoietic Stem and Progenitor Cell Research: IL-3 is widely used to support the expansion, differentiation, and maintenance of human hematopoietic stem and progenitor cells (HSPCs) in vitro. It is often combined with other cytokines to promote multilineage differentiation and colony formation in assays such as CFU (colony-forming unit) assays.

• Cell Culture and Bioassays: IL-3 is routinely used as a growth factor in cell culture systems, especially for the proliferation and differentiation of myeloid lineage cells, including basophils, mast cells, and macrophage precursors derived from human induced pluripotent stem cells (iPSCs). It is also used in bioassays to assess cytokine activity, such as the proliferation of TF-1 erythroleukemic cells.

• Immunological Studies: IL-3 has been validated for investigating immune cell function, including basophil and mast cell activation, T cell–basophil crosstalk, and the regulation of inflammatory responses. It is used to study basophil extravasation, cytokine production, and innate immune responses in both in vitro and in vivo models.

• Oncology and Chemotherapy Support: Clinical studies have validated IL-3 for its role in accelerating hematopoietic recovery post-chemotherapy, reducing treatment delays, and enhancing granulocyte and platelet regeneration in cancer patients. It has also been used in combination with other cytokines for peripheral blood stem cell mobilization and harvesting.

• Stem Cell and Organoid Research: IL-3 is applied in protocols for the differentiation of human pluripotent stem cells into myeloid and mesodermal lineages, as well as in organoid systems to model hematopoietic and immune cell development.

• In Vivo Models: Recombinant human IL-3 has been used in mouse models, including humanized mice expressing human IL-3, to study human immune responses, alveolar macrophage development, and lung inflammation.

• Functional Assays and Differentiation Protocols: IL-3 is validated for use in functional assays such as time-resolved fluoroimmunoassays (TRFIA), SDS-PAGE, mass spectrometry, and HPLC to assess protein activity, purity, and biological function.

• Cellular Disease Modeling: IL-3 is used in cellular models of diseases such as acute myeloid leukemia and β-thalassemia to study disease mechanisms and therapeutic interventions.

Summary Table of Validated Applications

These applications are supported by numerous peer-reviewed publications and are considered standard in the scientific use of recombinant human IL-3.

To reconstitute and prepare Recombinant Human IL-3 protein for cell culture experiments, first briefly centrifuge the vial to collect all lyophilized material at the bottom. Then, add sterile, distilled water or sterile PBS (pH 7.4) to achieve a final concentration between 0.1–1.0 mg/mL; concentrations of ≥100 μg/mL are generally recommended for stability. Gently mix by swirling or tapping—do not vortex or pipette vigorously to avoid protein denaturation.

Detailed protocol:

• Centrifuge the vial briefly before opening to ensure all powder is at the bottom.
• Add sterile water or PBS (pH 7.4) to reach the desired concentration (commonly 0.1–1.0 mg/mL; do not go below 100 μg/mL).
• Gently mix by swirling or tapping. Avoid vortexing or harsh pipetting.
• Aliquot the reconstituted solution to minimize freeze-thaw cycles.
• Storage:
  • Store aliquots at ≤–20°C or –80°C for long-term use (up to several months).
  • For short-term use, store at 4°C for up to 1 week.
• For cell culture: Further dilute the stock in cell culture medium or buffer containing a carrier protein (e.g., 0.1% BSA) to prevent adsorption and maintain stability.

Additional notes:

• Avoid repeated freeze-thaw cycles, as this can reduce protein activity.
• If using carrier-free IL-3, reconstitute in PBS; if the formulation contains BSA, follow the manufacturer’s instructions for dilution.
• Always consult the product-specific datasheet for any unique requirements, as formulations may vary.

Summary of best practices:

• Centrifuge, reconstitute in sterile water or PBS (≥100 μg/mL), mix gently, aliquot, and store at ≤–20°C. For working solutions, dilute in medium with carrier protein and use promptly to maintain bioactivity.