Recombinant Human Activin B

Recombinant Human Activin B is used in research applications because it is a multifunctional cytokine of the TGF-β superfamily, with key roles in regulating cell proliferation, differentiation, apoptosis, and signaling pathways relevant to development, disease, and regenerative medicine.

Key reasons to use Recombinant Human Activin B in research:

• Cellular Differentiation and Proliferation: Activin B is widely used to study mechanisms of mesoderm induction, neural cell differentiation, and bone remodeling, making it valuable for developmental biology and stem cell research.
• Signaling Pathway Analysis: It directly binds to Activin receptors (ActRII and ActRI), initiating SMAD-dependent signaling, which is central to TGF-β family research and understanding cellular responses to growth factors.
• Disease Modeling: Activin B is implicated in cancer biology (e.g., promoting tumorigenesis and cell invasion), metabolic regulation (e.g., improving insulin sensitivity and glucose metabolism), and erythropoiesis (red blood cell formation), making it useful for modeling and dissecting disease mechanisms.
• Immunomodulation and Wound Healing: It modulates immune responses and supports tissue repair, which is relevant for studies in inflammation, fibrosis, and regenerative medicine.
• Bioassay Standardization: Recombinant Activin B is used as a standard in bioassays (e.g., inducing hemoglobin expression in K562 cells), ensuring reproducibility and quantification in experimental protocols.

Typical applications include:

• Cell culture experiments to induce or inhibit specific differentiation pathways.
• Functional assays to study receptor-ligand interactions and downstream signaling.
• Disease models for cancer, metabolic disorders, and tissue regeneration.
• ELISA and other immunoassays as a standard or control protein.

Summary of scientific rationale:Using recombinant human Activin B allows for controlled, reproducible studies of its biological effects, enabling precise dissection of its roles in cellular and molecular processes relevant to human health and disease.

Yes, recombinant human Activin B can be used as a standard for quantification or calibration in ELISA assays, provided it is of high purity and bioactivity. This is a common practice in research ELISA protocols for quantifying proteins such as Activin B.

Key considerations and best practices:

• Purity and Activity: The recombinant Activin B should be well-characterized, with confirmed purity and biological activity. For example, recombinant human Activin B produced in CHO cells or other systems is routinely tested for activity (e.g., ability to induce hemoglobin expression in K562 cells).
• Carrier Protein: Recombinant proteins are often supplied either carrier-free or with BSA. For ELISA standards, using the version with BSA is generally recommended to enhance stability and reproducibility, unless BSA interferes with your assay.
• Calibration Range: The standard should be reconstituted and diluted according to the ELISA kit’s instructions, ensuring the concentration range matches the kit’s detection limits (e.g., 31.25 pg/mL – 1000 pg/mL).
• Matrix Effects: Use the sample diluent provided with your ELISA kit to minimize matrix effects and ensure accurate calibration.
• Validation: Confirm that your ELISA kit is specific for Activin B and does not cross-react with related proteins (e.g., Activin A, Activin AB, Inhibin A). Most commercial kits specify that their standards are recombinant proteins and provide validation data for specificity and recovery.
• Standard Curve Preparation: Prepare a fresh standard curve for each assay, using serial dilutions of the recombinant Activin B standard as described in the kit protocol.

Limitations:

• The recombinant standard should be used only for research purposes, not for clinical diagnostics, unless validated for such use.
• Always follow the manufacturer’s instructions for both the recombinant protein and the ELISA kit to ensure compatibility and accuracy.

Summary Table: Recombinant Activin B as ELISA Standard

In summary, recombinant human Activin B is suitable as a standard for ELISA quantification, provided it meets purity, activity, and compatibility requirements with your assay system.

Recombinant Human Activin B has been validated for a range of applications in published research, primarily in studies involving bioassays, cell culture, and functional activity assays. Key validated applications include:

• Bioassays: Used to assess biological activity, such as inhibition of cell proliferation (e.g., mouse plasmacytoma cell line MPC-11).
• Cell Culture: Applied to study effects on cell differentiation, proliferation, migration, and signaling in various cell types, including neural cells, bone marrow-derived mesenchymal stromal cells, and cancer cells.
• Surface Plasmon Resonance: Utilized for analyzing protein-protein interactions, such as receptor binding studies.
• Gene Expression Modulation: Investigated for its role in regulating genes involved in glucose metabolism, such as induction of FGF21 and suppression of hepatic glucose production in hepatocytes.
• Functional Studies in Disease Models: Used to explore its effects on inflammation, mucosal proliferation, cancer cell migration/invasion, and metabolic regulation in animal models and human cells.

Additional validated research contexts include:

• Embryonic development and mesoderm induction
• Neural cell differentiation
• Bone remodeling
• Regulation of hepcidin expression and iron metabolism
• Immunomodulation and wound healing
• Regenerative medicine and tissue repair
• Reproductive health and cancer therapy.

Summary Table of Validated Applications

These applications are supported by peer-reviewed publications and product validation data, confirming the utility of recombinant human Activin B in diverse experimental systems relevant to developmental biology, metabolism, immunology, and oncology.

To reconstitute and prepare Recombinant Human Activin B protein for cell culture experiments, dissolve the lyophilized protein at a concentration of 100 μg/mL in 4 mM HCl or, alternatively, in sterile ultrapure water at not less than 100 μg/mL, depending on the specific product instructions. After reconstitution, further dilute the protein in appropriate cell culture media or buffer for your experiment.

Detailed protocol and best practices:

• Centrifuge the vial briefly before opening to ensure all lyophilized material is at the bottom.
• Add the recommended volume of sterile 4 mM HCl (or sterile ultrapure water if specified by your supplier) to achieve a concentration of 100 μg/mL.
• Gently mix by pipetting or swirling. Avoid vigorous shaking or vortexing to prevent protein denaturation or foaming.
• Allow the protein to dissolve at room temperature for 15–30 minutes with gentle agitation.
• If required, add a carrier protein (such as 0.1% BSA or HSA) to improve stability, especially if storing at low concentrations or for long-term storage.
• Aliquot the reconstituted protein to avoid repeated freeze-thaw cycles, which can reduce activity.
• Storage after reconstitution:
  • Short-term (2–7 days): 2–8 °C.
  • Long-term: ≤ –18 °C, preferably with carrier protein.
• Working dilution: Prepare fresh dilutions in cell culture medium immediately before use. The effective working concentration for biological activity is typically in the range of 0.2–4 ng/mL, but this should be optimized for your specific assay.

Summary Table: Reconstitution and Handling

Always consult the specific product datasheet or certificate of analysis for any unique requirements, as formulation and recommended diluents may vary between suppliers.