Recombinant Human CD137R (4-1BBR)

Recombinant Human CD137R (4-1BBR) offers several compelling advantages for research applications, particularly in immunology and therapeutic development.

Immune Modulation and T Cell Enhancement

CD137R functions as a costimulatory receptor that significantly amplifies T cell responses when engaged appropriately. The spatial configuration of costimulation matters considerably—when CD137 costimulation is provided in cis (on the same cell as the TCR-CD3 complex) relative to antigen presentation, it produces superior outcomes compared to trans presentation in terms of T cell activation, proliferation, survival, and cytokine secretion. This enhanced signaling results in more intense canonical and non-canonical NF-κB signaling pathways and robust induction of cell cycle and DNA damage repair gene expression programs.

Cancer Immunotherapy Applications

The CD137 pathway demonstrates powerful anti-tumor properties through multiple mechanisms. CD137 signaling activates cytotoxic T lymphocytes (CTLs) and induces high amounts of interferon-gamma (IFN-γ) production. Recombinant CD137-Fc fusion proteins act synergistically with other cancer treatments to eradicate both nonimmunogenic and weakly immunogenic tumors. When combined with dendritic cell-based approaches or CAR T cell therapies, CD137 engagement enhances tumor regression and establishes long-lasting tumor-specific immunological memory.

Broad Therapeutic Potential

Beyond oncology, recombinant CD137R has applications across multiple disease contexts. The CD137-CD137L axis plays a critical role in maintaining effective T cell immune responses and can modulate immune responses to treat various immune disorders. CD137 activation induces interleukin-13 (IL-13) production in both CD8+ and CD4+ T cells, which reduces inflammation. This dual functionality makes it valuable for studying both antiviral immunity and autoimmune conditions.

Inflammatory Response Modulation

Recombinant CD137-Fc has demonstrated the ability to reduce secretion of pro-inflammatory cytokines IL-6 and IL-8 by approximately 50% in leukocyte-rich plasma samples, indicating potential utility in studying cytokine release syndrome and inflammatory conditions. This property extends to viral infection models, where CD137 engagement may reduce lung tissue inflammation and improve patient outcomes.

Research Flexibility

The recombinant format allows for standardized, reproducible experiments with well-characterized biological activity. The protein can be produced in various expression systems and modified with different fusion partners and linkers to optimize activity for specific research applications.

You can use recombinant human CD137R (4-1BBR) as a standard for quantification or calibration in ELISA assays, provided that the ELISA is validated to recognize both natural and recombinant forms of the protein. Many commercial ELISA kits for CD137 (4-1BB) specifically state that their assays are designed to detect both natural and recombinant human CD137, and they often use recombinant protein as the standard for generating calibration curves.

Key considerations:

• Ensure that the recombinant protein you use is of high purity and its concentration is accurately determined, as this will directly affect the accuracy of your standard curve.
• The epitope recognized by the ELISA antibodies must be present and accessible on your recombinant protein. Most sandwich ELISAs for CD137 are validated for both natural and recombinant forms, but if you are developing a custom assay, you should confirm cross-reactivity.
• The standard curve should be prepared in the same matrix as your samples (e.g., buffer, serum, or plasma) to minimize matrix effects and ensure accurate quantification.
• If your recombinant CD137R is tagged or otherwise modified, verify that these modifications do not interfere with antibody binding in the ELISA.

Protocol best practices:

• Prepare a serial dilution of the recombinant standard in the recommended diluent.
• Include the standard curve in every assay plate for reliable quantification.
• Validate the linearity and sensitivity of your assay using the recombinant standard.

In summary, recombinant human CD137R is suitable as a standard for ELISA quantification, as long as the assay is validated for this use and the protein is properly characterized.

Recombinant Human CD137R (4-1BBR) has been validated in published research for several key applications, primarily in the context of immunological assays and functional studies related to T cell costimulation, cancer immunotherapy, and immune modulation.

Validated Applications in Published Research:

• Bioassays: Recombinant CD137R is widely used in bioassays to study its interaction with CD137 ligand (CD137L) and to assess downstream immune responses. For example, it has been used to:

  • Evaluate the ability of CD137L-stimulated dendritic cells to elicit cytotoxic T-cell responses.
  • Investigate the association of tumor necrosis factor receptor 1 with CD137 ligand and its role in reverse signaling.
  • Study the engagement of CD137 by human γδ T lymphocytes and the resulting NK cell-mediated antitumor cytotoxicity.
  • Measure the inhibitory effect of recombinant CD137R on CD137L-mediated stimulation of IL-8 production by human peripheral blood mononuclear cells (PBMCs).

• Functional Immunology Studies: Recombinant CD137R has been used to dissect the mechanisms of T cell activation, proliferation, cytokine secretion, and memory formation, particularly in the context of cancer immunotherapy and immune checkpoint modulation.

• Cancer Immunotherapy Research: Recombinant CD137R and its fusion proteins (such as CD137-Fc) have been validated in preclinical and clinical studies for their role in:

  • Enhancing antitumor immune responses by providing costimulatory signals to T cells.
  • Serving as a component in the development of bispecific antibodies and chimeric antigen receptor (CAR) constructs for targeted immunotherapy.

• Autoimmunity and Infectious Disease Models: Recombinant CD137R has been explored as an immune modulator in models of autoimmune disease and viral infection, including COVID-19, due to its dual role in enhancing antiviral and antitumor responses while potentially alleviating autoimmune conditions.

Summary Table of Validated Applications

Additional Notes:

• Recombinant CD137R is typically used in in vitro systems with human cells, including PBMCs and dendritic cells, to model immune interactions and signaling pathways.
• Its applications are supported by both mechanistic studies (e.g., signaling, cytokine production) and translational research (e.g., immunotherapy development).

If you require detailed protocols or specific assay formats (e.g., ELISA, flow cytometry), please specify, as these are also common applications for recombinant CD137R and related reagents.

To reconstitute and prepare Recombinant Human CD137R (4-1BBR) protein for cell culture experiments, use sterile technique and follow these steps:

1. Centrifuge the vial briefly to ensure all lyophilized protein is at the bottom before opening.
2. Add sterile distilled water or buffer (such as PBS) to the vial. The recommended concentration for reconstitution is typically 0.1–1.0 mg/mL. For example, if you have 100 µg of protein, add 100 µL to 1 mL of diluent.
3. Include a carrier protein (such as 0.1% bovine serum albumin (BSA) or 5–10% fetal bovine serum (FBS)) in the buffer to stabilize the protein and prevent adsorption to surfaces.
4. Gently mix by pipetting or slow vortexing. Avoid vigorous shaking or foaming, which can denature the protein.
5. Allow the protein to dissolve for 15–30 minutes at room temperature with gentle agitation.
6. Aliquot the solution to avoid repeated freeze-thaw cycles, which can degrade the protein.
7. Storage:
   • Short-term: Store reconstituted protein at 2–8°C for up to one week.
   • Long-term: Store aliquots at –20°C to –80°C for extended periods.

Additional notes for cell culture experiments:

• Filter-sterilize the final solution if required for cell culture.
• For functional assays, further dilute the protein in cell culture medium containing serum or carrier protein to maintain stability.
• Always consult the specific product datasheet for any unique requirements regarding buffer composition or reconstitution protocol.

Summary Table: Recombinant CD137R (4-1BBR) Reconstitution

This protocol ensures optimal solubility, stability, and biological activity of recombinant CD137R for cell culture applications.