Recombinant Human CD80

Recombinant Human CD80 is widely used in research because it is a key immune co-stimulatory molecule that modulates T cell activation, immune checkpoint pathways, and has applications in immunotherapy, tumor biology, and autoimmune disease models.

Key scientific reasons to use recombinant human CD80 in research applications:

• T Cell Co-stimulation: CD80 (also known as B7-1) is expressed on antigen-presenting cells and provides a critical co-stimulatory signal to T cells by binding to CD28, enhancing T cell activation, proliferation, and cytokine production. This is essential for studying T cell responses in vitro and in vivo.

• Immune Checkpoint Modulation: CD80 also binds to CTLA-4 and PD-L1, modulating immune checkpoint pathways. Soluble or recombinant CD80 can block the PD-1/PD-L1 interaction, thereby restoring T cell activity and overcoming immune suppression, which is particularly relevant in cancer immunotherapy research.

• Antitumor and Antiviral Immunity: Recombinant CD80 has been shown to enhance antitumor immunity by providing co-stimulatory signals and by blocking inhibitory pathways. It can be used to model or enhance immune responses against tumors or viral infections in preclinical studies.

• Autoimmune and Inflammatory Disease Models: Because CD80 is involved in T cell activation, recombinant forms can be used to study or modulate immune responses in models of autoimmune diseases, such as multiple sclerosis or lupus, and to investigate mechanisms of immune regulation.

• Soluble CD80 as an Immunomodulator: Recombinant soluble CD80 (sCD80) can act as an immunomodulatory agent, either inhibiting or enhancing T cell responses depending on the context. For example, sCD80 can inhibit T cell proliferation in mixed lymphocyte reactions, making it useful for studying immune tolerance or hyperactivation.

• Mechanistic Studies: Recombinant CD80 enables precise dissection of its interactions with CD28, CTLA-4, and PD-L1, allowing for detailed mechanistic studies of immune synapse formation, signaling pathways (such as NF-κB activation), and checkpoint regulation.

• Therapeutic Development: Recombinant CD80 proteins, including engineered variants and fusion proteins, are used as tools to develop and test new immunotherapeutic strategies, such as checkpoint inhibitors, CAR-T cell enhancements, or as adjuvants in vaccine research.

• Standardization and Reproducibility: Using recombinant human CD80 ensures batch-to-batch consistency, defined purity, and scalability, which are critical for reproducible experimental results and for translational research applications.

In summary, recombinant human CD80 is a versatile reagent for immunological research, enabling the study and manipulation of T cell co-stimulation, immune checkpoint pathways, and the development of novel immunotherapies.

Yes, Recombinant Human CD80 can be used as a standard for quantification or calibration in ELISA assays, provided it is of high purity, its concentration is accurately determined, and it matches the form of CD80 you intend to measure.

Essential context and supporting details:

• Purity and Quantification: For reliable ELISA calibration, the standard should be a purified protein or a well-characterized recombinant protein. The concentration must be accurately measured, typically by UV absorbance or HPLC. Recombinant Human CD80 proteins are routinely used as standards in commercial ELISA kits, indicating their suitability for this purpose.

• Formulation Considerations: Recombinant CD80 is available in different formulations (e.g., carrier-free, with BSA). Carrier-free versions are preferred if BSA or other additives could interfere with your assay. Lyophilized proteins should be reconstituted according to manufacturer instructions to ensure consistency.

• Standard Curve Preparation: Prepare a standard curve using serial dilutions of the recombinant CD80 in the same buffer as your samples. The curve should cover the expected concentration range of CD80 in your samples, typically from low picogram to nanogram per milliliter levels.

• Validation: Ensure the recombinant CD80 standard is compatible with your assay’s antibodies and detection system. Analytical validation (e.g., recovery, linearity, specificity) is recommended, especially if you are developing a custom ELISA.

• Isoform and Tag Considerations: Confirm that the recombinant CD80 matches the isoform and epitope recognized by your ELISA antibodies. Tags (e.g., His-tag) generally do not interfere with quantification unless the antibody binding site overlaps with the tag region.

Best practices:

• Use freshly prepared standards for each assay run to minimize variability.
• Store aliquots of reconstituted protein at recommended temperatures and avoid repeated freeze-thaw cycles.
• Validate the standard curve with known concentrations to ensure accuracy and reproducibility.

In summary, Recombinant Human CD80 is suitable as an ELISA standard if it is properly characterized, matches your assay requirements, and is handled according to best laboratory practices.

Applications of Recombinant Human CD80 in Published Research

Recombinant human CD80 has been validated across several significant immunological and therapeutic applications in published research:

T Cell Activation and Co-stimulation

The primary validated application involves T cell activation and proliferation. CD80 functions as a co-stimulatory ligand that binds to CD28 on T cells, enhancing cell activation, proliferation, and cytokine production when presented on antigen-presenting cells. This fundamental mechanism has been leveraged in multiple therapeutic contexts where enhanced T cell responses are therapeutically beneficial.

Cancer Immunotherapy

CD80-based therapeutics have demonstrated substantial anti-tumor efficacy in published studies. Recombinant CD80-Fc fusion proteins have been shown to effectively activate T cells and inhibit tumor growth in vivo, even in tumors with poor response to immune checkpoint inhibitors. Engineered CD80 variants with enhanced PD-L1 affinity have been validated to combine CD28 costimulation with dual checkpoint inhibition, demonstrating enhanced T cell activation and anti-tumor efficacy in both cell-based assays and mouse tumor models more potently than checkpoint blockade alone.

Research has specifically validated CD80 as a molecular target in T cell anti-tumor immune responses, with particular efficacy against hematological malignancies. Studies demonstrated strong cytotoxicity against CD80-positive B cell lymphomas, including Raji cells and Reed-Sternberg cells, suggesting CD80 as a potential therapeutic target for B-cell lymphomas.

Functional Assays

Recombinant CD80 has been validated for use in functional ELISA assays measuring binding ability and in IL-2 secretion assays using Jurkat T cells as a bioactivity readout. These assays confirm the biological activity of the recombinant protein and its capacity to engage T cell receptors appropriately.

Immunological Disease Research

CD80-positive B cells have been identified as potential therapeutic targets for autoimmune and inflammatory conditions, including HTLV-1-related myelopathy/tropical spastic paraparesis and multiple sclerosis. Additionally, CD80 expression on antigen-presenting cells has been documented in patients with Minimal Change Nephropathy, establishing its relevance in glomerular disease research.

To reconstitute and prepare Recombinant Human CD80 protein for cell culture experiments, dissolve the lyophilized protein in sterile phosphate-buffered saline (PBS) to a concentration of 500 μg/mL. Use gentle agitation and avoid vigorous shaking to prevent foaming and protein denaturation.

Step-by-step protocol:

• Centrifuge the vial briefly before opening to ensure all powder is at the bottom.
• Add sterile PBS to achieve the recommended concentration (e.g., 500 μg/mL for carrier-free CD80).
• Gently mix by inverting or tapping; let the vial sit at room temperature for 15–30 minutes to fully dissolve the protein.
• Avoid vigorous shaking to prevent foaming and loss of activity.
• For short-term use (up to one week), store the reconstituted protein at 2–8 °C.
• For long-term storage, aliquot the solution and store at −20 °C or −80 °C. Adding a carrier protein such as 0.1% BSA can help stabilize the protein, especially at low concentrations.
• Avoid repeated freeze–thaw cycles to maintain protein integrity.

Additional considerations:

• If your cell culture system is sensitive to animal proteins (e.g., serum-free or in vivo experiments), avoid BSA or FBS as carriers; consider using trehalose for stabilization.
• Always consult the product’s Certificate of Analysis (CoA) for specific instructions, as buffer requirements and concentrations may vary by lot or manufacturer.
• For experimental use, dilute the stock solution to the desired working concentration using cell culture medium or buffer containing carrier protein to minimize adsorption losses.

Summary Table:

Following these steps will ensure optimal activity and stability of recombinant CD80 for cell culture experiments.