Recombinant Human Plasma Selectin (P-selectin)

Using Recombinant Human Plasma Selectin (P-selectin) in research applications is valuable for studying and manipulating cell adhesion, inflammation, thrombosis, tumor biology, and immune cell interactions. Recombinant P-selectin provides a controlled, defined tool to probe the molecular mechanisms underlying these processes and to develop or test therapeutic strategies.

Key scientific applications and rationale include:

• Modeling Leukocyte Recruitment and Adhesion: P-selectin is a critical adhesion molecule expressed on activated platelets and endothelial cells, mediating the initial recruitment and rolling of leukocytes (such as neutrophils and monocytes) at sites of vascular injury or inflammation by binding to its ligand PSGL-1. Recombinant P-selectin allows you to reconstitute and study these interactions in vitro, enabling precise dissection of the molecular events in leukocyte-endothelial or leukocyte-platelet adhesion.

• Investigating Platelet and Tumor Interactions: P-selectin facilitates platelet accumulation within solid tumors, which can promote tumor growth and metastasis. Recombinant soluble human P-selectin has been shown to inhibit platelet infiltration and suppress tumor growth in xenograft models, making it a useful tool for cancer biology studies and for evaluating anti-metastatic strategies.

• Studying Immune Modulation and Antigen Presentation: P-selectin is involved in modulating immune responses, including enhancing dendritic cell cross-presentation and T cell activation. Recombinant P-selectin can restore immune cell function in systems where platelets are depleted, supporting research into immunotherapy and antigen presentation mechanisms.

• Analyzing Thrombosis and Vascular Disease: Soluble P-selectin (sP-selectin) in plasma is a biomarker and functional mediator in vascular diseases such as peripheral arterial occlusive disease (PAOD). Recombinant sP-selectin can be used to study its effects on neutrophil adhesion, platelet-leukocyte interactions, and the signaling pathways involved in vascular inflammation and thrombosis.

• Assay Development and Cell Capture: Recombinant P-selectin is used in ELISA development, binding assays, and for the capture/enrichment of specific cell populations (e.g., CD34+ hematopoietic stem cells) from blood, leveraging its specific binding to PSGL-1 and related ligands.

• Therapeutic Target Validation: By using recombinant P-selectin in blocking or competition assays, researchers can validate the efficacy of P-selectin antagonists or inhibitors in reducing leukocyte adhesion, platelet aggregation, or tumor progression, supporting drug discovery efforts.

In summary, recombinant human P-selectin is a versatile reagent for dissecting the molecular basis of cell adhesion, inflammation, thrombosis, tumor biology, and immune responses, and for developing diagnostic and therapeutic strategies targeting these pathways.

Yes, recombinant human P-selectin (plasma selectin) can be used as a standard for quantification or calibration in ELISA assays, provided it is properly characterized and compatible with your assay system. This approach is widely accepted in research ELISA protocols for quantifying human P-selectin in biological samples.

Supporting details:

• ELISA Calibration: Commercial ELISA kits for human P-selectin routinely use purified recombinant human P-selectin as the standard for generating calibration curves. These standards are used to interpolate the concentration of P-selectin in unknown samples by comparing their signal to the standard curve.

• Assay Compatibility: The antibodies in these ELISA kits are raised against recombinant human P-selectin and are validated to recognize both recombinant and natural forms of the protein. Assay validation data show that curves generated with natural and recombinant P-selectin are parallel, indicating equivalence for quantification purposes.

• Recovery and Specificity: Recovery experiments demonstrate that recombinant P-selectin spiked into plasma, serum, or cell culture media is accurately measured by ELISA, with recovery rates typically between 90–110%. The assays are specific for human P-selectin and do not cross-react with other selectins.

• Best Practices:

  • Ensure your recombinant standard is soluble, properly folded, and quantified (e.g., by BCA or absorbance at 280 nm).
  • Prepare serial dilutions in the same buffer or matrix as your samples to minimize matrix effects.
  • Validate parallelism between your standard curve and endogenous sample curves, especially if your recombinant protein differs in glycosylation or tag structure from native P-selectin.

• Limitations: Use recombinant standards only for research purposes; they are not validated for diagnostic use. If your recombinant protein has modifications (e.g., tags, altered glycosylation), confirm that these do not affect antibody recognition or assay performance.

In summary: Recombinant human plasma selectin is suitable as a standard for ELISA quantification, provided it is well-characterized and compatible with your assay antibodies and conditions.

Recombinant Human Plasma Selectin (P-selectin) has been validated for a range of applications in published research, primarily in studies of cell adhesion, inflammation, thrombosis, cancer, and as a tool in immunological assays.

Key validated applications include:

• Cell adhesion assays: Recombinant P-selectin has been used to study neutrophil adhesion to fibrinogen and platelets, demonstrating its role in leukocyte recruitment and activation under both static and flow conditions. It has been shown to dose-dependently increase neutrophil adhesion and upregulate integrin activation via PSGL-1-dependent signaling.

• ELISA and immunoassays: Recombinant P-selectin is commonly used as a standard or positive control in ELISA development, Western blotting, and immunoprecipitation to detect or quantify P-selectin or its ligands.

• Bioassays and binding assays: It has been employed in bioassays to study interactions with ligands such as PSGL-1, and in binding assays to characterize molecular interactions relevant to inflammation and thrombosis.

• In vivo functional studies: Soluble recombinant P-selectin has been used in animal models to:

  • Restore hemostasis in hemophilia.
  • Rescue from viper venom-induced mortality.
  • Protect liver endothelial cells from ischemia-reperfusion injury.
  • Ameliorate inflammation by competing with endogenous P-selectin for ligand binding.

• Cancer research and drug delivery: P-selectin is targeted in nanoparticle-based drug delivery systems for tumors expressing high levels of P-selectin, enabling selective delivery of chemotherapeutics and immunomodulators to the tumor microenvironment.

• Stem cell capture and enrichment: Recombinant P-selectin has been used to capture and enrich CD34-positive hematopoietic stem and progenitor cells from blood, leveraging its ligand specificity.

• Immunological and mechanistic studies: It serves as a tool to dissect the molecular mechanisms of leukocyte rolling, adhesion, and recruitment during inflammation and vascular injury.

Additional notes:

• Recombinant P-selectin is also used as a research reagent to validate anti-P-selectin antibodies and aptamers, and to study the inhibition of cell adhesion in disease models such as sickle cell disease.
• It is frequently used as a positive control in various immunological experiments, although some commercial preparations may not have their biological activity independently validated.

Summary Table of Validated Applications

These applications are supported by peer-reviewed studies and are widely adopted in vascular biology, immunology, and translational research.

To reconstitute and prepare Recombinant Human Plasma Selectin (P-selectin) for cell culture experiments, add sterile distilled water or the buffer specified in the product datasheet to the lyophilized protein, gently mix to dissolve, and, if required, further dilute in cell culture-compatible buffer containing carrier protein such as BSA or HSA to prevent adsorption and maintain stability.

Detailed protocol and best practices:

• Equilibrate the lyophilized vial and the reconstitution buffer (sterile distilled water or specified buffer) to room temperature before opening to minimize condensation.
• Centrifuge the vial briefly to collect all powder at the bottom.
• Add the recommended volume of sterile distilled water or buffer as indicated on the product datasheet or vial label (commonly 0.2–1 mL, but always check the specific instructions).
• Gently swirl or invert the vial to dissolve the protein completely. Avoid vigorous shaking or vortexing, which can denature the protein.
• Allow the protein to dissolve for 15–30 minutes at room temperature. If visible particulates remain, gently mix for up to 2 hours.
• Optional: For cell culture applications, especially at low concentrations, add a carrier protein (e.g., 0.1–1% BSA or HSA) to the buffer to stabilize the protein and prevent loss due to adsorption to plastic surfaces.
• Filter sterilize the solution using a 0.2 μm filter if sterility is required and the protein is not already provided sterile.
• Aliquot and store the reconstituted protein at –20 °C or –80 °C if not used immediately. Avoid repeated freeze-thaw cycles to maintain activity.

Dilution for cell culture:

• Prepare working solutions in cell culture medium or PBS with carrier protein as needed, ensuring compatibility with your downstream assay or cell type.
• Typical working concentrations for functional assays range from 0.1–10 μg/mL, but optimal concentrations should be determined empirically for your specific application.

Critical notes:

• Always consult the specific product datasheet for precise reconstitution volume and buffer recommendations, as formulations may vary between suppliers.
• If the protein is to be immobilized (e.g., for cell adhesion assays), additional activation or coupling steps may be required.

Summary of key steps:

• Bring vial and buffer to room temperature.
• Centrifuge vial briefly.
• Add specified volume of sterile water or buffer.
• Gently mix to dissolve.
• Add carrier protein if needed.
• Filter sterilize if required.
• Aliquot and store appropriately.

Following these steps ensures optimal solubility, stability, and biological activity of recombinant P-selectin for cell culture experiments.