Recombinant Human IL-16

Recombinant Human IL-16 is used in research applications to study immune cell signaling, modulation of immune responses, and disease mechanisms due to its role as a cytokine with chemoattractant, immunomodulatory, and antiviral properties.

Key scientific reasons to use recombinant human IL-16 include:

• Chemoattractant Activity: IL-16 is a potent chemoattractant for CD4⁺ T cells, monocytes, and eosinophils, making it valuable for investigating immune cell migration and recruitment in vitro and in vivo.
• Modulation of T Cell Activation: IL-16 can modulate T cell activation, induce the expression of activation markers such as CD25, and synergize with other cytokines to activate CD4⁺ T cells.
• Th1 Polarization and Anti-Tumor Immunity: IL-16 administration enhances Th1 cell differentiation and IFN-γ production, reprograms tumor-associated macrophages toward an M1-like phenotype, and improves the efficacy of immune checkpoint blockade therapies in cancer models. This makes it a tool for studying tumor immunology and immunotherapy mechanisms.
• Antiviral Effects: Recombinant IL-16 has been shown to inhibit HIV-1 replication in acutely infected T cells and protect against apoptosis in certain contexts, supporting its use in virology and HIV research.
• Cell Signaling Studies: IL-16 facilitates crosslinking of CD4 and CCR5 on target cells, enhancing cell signaling pathways relevant to immune cell function and HIV entry.
• Disease Modeling: IL-16 is implicated in the pathogenesis of autoimmune diseases, multiple myeloma, and other conditions, making recombinant protein useful for dissecting disease mechanisms and testing therapeutic interventions.

Typical applications for recombinant human IL-16 include:

• Chemotaxis assays to study immune cell migration.
• Functional assays of T cell activation and differentiation.
• Tumor microenvironment modeling and immunotherapy research.
• HIV replication and apoptosis assays in primary immune cells.
• Mechanistic studies of cytokine signaling and receptor interactions.

Best practices for using recombinant IL-16:

• Confirm bioactivity and purity, as folding and multimerization state can affect function.
• Use appropriate concentrations based on published dose-response data, as higher concentrations may be required for bacterially expressed protein due to folding differences.
• Validate effects in relevant cell types (e.g., CD4⁺ T cells, monocytes, macrophages) and experimental systems.

In summary, recombinant human IL-16 is a versatile tool for immunology, oncology, and virology research, enabling precise investigation of cytokine-mediated processes and therapeutic strategies.

Yes, recombinant human IL-16 can be used as a standard for quantification or calibration in ELISA assays, provided it is properly validated and matched to your assay system.

Key considerations and supporting details:

• Recombinant IL-16 is commonly used as a standard in commercial ELISA kits for human IL-16 quantification. These kits typically use recombinant IL-16 (often E. coli-derived) to generate the standard curve, against which unknown samples are measured.

• Validation and comparability: Studies and kit documentation indicate that recombinant IL-16 standards produce standard curves that are parallel to those generated with natural IL-16, allowing for accurate quantification of both recombinant and endogenous IL-16 in biological samples. This parallelism is essential for reliable quantification.

• Formulation and handling: Recombinant IL-16 used as a standard is often supplied lyophilized and should be reconstituted according to the manufacturer’s instructions, typically in PBS with carrier protein (such as BSA) to prevent adsorption and degradation. Proper storage and avoidance of repeated freeze-thaw cycles are important for maintaining protein integrity.

• Assay compatibility: Ensure that the recombinant IL-16 standard matches the detection antibodies’ epitope specificity in your ELISA. Most commercial kits are designed to recognize both natural and recombinant forms, but if you are developing a custom assay, confirm that your antibodies detect the recombinant standard equivalently to native IL-16.

• Concentration range: Recombinant IL-16 standards are typically used to generate calibration curves in the range of 5–3000 pg/mL, which covers the expected physiological and experimental concentrations.

• Documentation: When using recombinant IL-16 as a standard outside of a commercial kit, document the source, lot, and reconstitution protocol, and validate the standard curve for linearity, accuracy, and parallelism with your sample matrix.

Summary Table: Use of Recombinant Human IL-16 as ELISA Standard

In summary: You can use recombinant human IL-16 as a standard for ELISA quantification, provided it is validated for your assay and handled according to best practices.

Recombinant Human IL-16 has been validated for several key applications in published research, primarily in bioassays and ELISA (enzyme-linked immunosorbent assay) formats.

Validated Applications in Published Research:

• Bioassay:
  Recombinant Human IL-16 is widely used in cell-based bioassays to study its biological activity, such as chemotactic effects on lymphocytes, modulation of macrophage activation, and cytokine release. For example:

  • It has been used to assess chemotactic activity for CD4+ lymphocytes and to study its role as a chemoattractant.
  • It has been applied to investigate modulation of macrophage activation, including upregulation of phagocytosis and cytokine expression (e.g., IL-1α, IL-6, IL-12) in M0 macrophages.
  • Studies have used recombinant IL-16 to examine its effects on T cell activation, including upregulation of IL-2 receptor subunits and enhancement of IL-2-mediated proliferation.
  • It has been employed to explore its inhibitory effects on HIV-1 replication in vitro.

• ELISA (Standard):
  Recombinant Human IL-16 is used as a standard in ELISA assays to quantify IL-16 levels in biological samples, particularly in studies of immune activation and disease states such as HIV infection.

  • Examples include measurement of IL-16 in lymphoid tissues and lymph nodes from HIV-1 infected individuals.

• Cellular Modulation Studies:
  Recombinant IL-16 has been validated for use in experiments investigating its ability to modulate surface receptor expression and cytokine release in monocyte-derived macrophages and monocyte cell lines.

Additional Context:

• Disease Models:
  Recombinant IL-16 has been used in animal and cell models to study its role in inflammatory, autoimmune, and infectious diseases, as well as cancer. For instance, blockade or administration of IL-16 has been tested for therapeutic effects in models of colitis and MRSA pneumonia.

• Mechanistic Studies:
  It is applied in mechanistic studies to elucidate signaling pathways (e.g., JAK, NF-κB) and cellular responses such as pyroptosis and immune cell migration.

Summary Table of Validated Applications

These applications are supported by multiple peer-reviewed publications and reviews, confirming the utility of recombinant human IL-16 in immunological, infectious disease, and cell biology research.

To reconstitute and prepare Recombinant Human IL-16 protein for cell culture experiments, follow these steps for optimal protein stability and biological activity:

1. Equilibrate and Centrifuge

   • Allow the lyophilized IL-16 vial and your reconstitution buffer to reach room temperature (18–25°C).
   • Briefly centrifuge the vial to collect all powder at the bottom.

2. Reconstitution Buffer Selection

   • Use sterile PBS (phosphate-buffered saline) or sterile distilled water as the base buffer.
   • For cell culture applications, it is strongly recommended to include a carrier protein such as 0.1% BSA (bovine serum albumin), 10% FBS (fetal bovine serum), or 5% HAS (human albumin solution) in the buffer to prevent protein loss due to adsorption and to enhance stability.

3. Reconstitution Concentration

   • Typical reconstitution concentrations are 0.1–1.0 mg/mL (100–1000 μg/mL).
   • For example, to achieve 0.1 mg/mL, add 100 μL buffer to 10 μg protein, or 1 mL buffer to 100 μg protein.
   • Gently pipette the buffer down the side of the vial to dissolve the powder. Do not vortex; mix by gentle swirling or inversion.

4. Dissolution and Inspection

   • Allow the vial to stand at room temperature for 15–30 minutes with gentle agitation.
   • If undissolved particulates remain, continue gentle mixing for up to 2 hours at room temperature or overnight at 4°C.

5. Aliquoting and Storage

   • Once fully dissolved, aliquot the solution to avoid repeated freeze-thaw cycles.
   • For short-term storage (up to 1 week), keep at 2–8°C.
   • For long-term storage, dilute with buffer containing carrier protein, aliquot, and store at –20°C to –80°C.
   • Optionally, add 5–50% glycerol for enhanced stability during long-term storage.

6. Working Solution Preparation

   • Before adding to cell cultures, dilute the reconstituted IL-16 to the desired working concentration using cell culture medium or buffer containing carrier protein.
   • Avoid repeated freeze-thaw cycles by using single-use aliquots.

Key technical notes:

• Carrier-free IL-16 is available for applications where BSA or other proteins may interfere, but for most cell culture work, inclusion of a carrier protein is recommended for stability.
• Always consult the specific product’s Certificate of Analysis (CoA) or data sheet for any unique instructions.
• For serum-free or in vivo applications, use a non-protein stabilizer such as trehalose instead of BSA or FBS.

Summary Table: IL-16 Reconstitution for Cell Culture

Following these steps will ensure maximum stability and biological activity of recombinant human IL-16 for cell culture experiments.