Recombinant Human CCL17/TARC

Recombinant Human CCL17/TARC is used in research to study immune cell migration, inflammation, and disease mechanisms because it is a chemokine that specifically attracts T-helper 2 (Th2) cells and regulatory T cells (Tregs) via the CCR4 receptor. This makes it a valuable tool for dissecting immune responses in allergy, autoimmunity, cancer, and infectious disease models.

Key scientific applications and rationale include:

• Chemotaxis Assays: CCL17/TARC is a potent chemoattractant for Th2 cells and Tregs, allowing you to model and quantify immune cell migration in vitro and in vivo.
• Immune Cell Signaling Studies: It activates intracellular pathways such as MAPK and NF-κB in CCR4-expressing cells, enabling investigation of downstream signaling events relevant to inflammation and cancer.
• Disease Modeling: CCL17/TARC is implicated in asthma, allergic diseases, autoimmune disorders, and certain cancers (e.g., cutaneous T-cell lymphoma, Merkel cell carcinoma), making it essential for studying disease pathogenesis and therapeutic interventions.
• Biomarker and Therapeutic Target Validation: Elevated CCL17/TARC levels are associated with disease activity in several conditions, supporting its use in biomarker discovery and validation studies.
• ELISA and Bioassay Standards: Recombinant CCL17/TARC is used as a standard in immunoassays to quantify endogenous protein levels in biological samples.

Additional context:

• Tissue Expression: CCL17 is constitutively expressed in the thymus and upregulated in inflamed tissues, reflecting its physiological and pathological roles.
• Specificity: It selectively attracts T cells, not monocytes or neutrophils, allowing for targeted studies of adaptive immunity.
• Wound Healing and Neuroinflammation: CCL17 also contributes to fibroblast migration in wound healing and modulates microglial morphology in the brain, broadening its research utility.

In summary, recombinant human CCL17/TARC is a critical reagent for immunology, inflammation, and disease research, enabling precise manipulation and measurement of immune cell behavior and signaling pathways relevant to human health and disease.

Yes, recombinant human CCL17/TARC can be used as a standard for quantification or calibration in ELISA assays, provided it is of high purity, properly quantified, and compatible with your assay system. This is a common and accepted practice in quantitative immunoassays for cytokines and chemokines.

Supporting details:

• Recombinant CCL17/TARC is routinely used as a standard in commercial ELISA kits for the quantification of CCL17/TARC in biological samples such as serum, plasma, and cell culture supernatants. These kits typically include a recombinant CCL17/TARC standard to generate a calibration curve, against which unknown sample concentrations are interpolated.

• Validation and comparability: Studies and kit documentation indicate that recombinant CCL17/TARC standards produce standard curves that are parallel to those generated with natural CCL17/TARC, supporting their use for accurate quantification. Recovery experiments show good recovery rates when recombinant CCL17/TARC is spiked into various matrices, further validating its suitability as a standard.

• Best practices:

  • Ensure the recombinant protein is quantified accurately (e.g., by amino acid analysis or absorbance at 280 nm with a known extinction coefficient).
  • Use the same buffer or diluent for preparing the standard curve as is used for your samples to minimize matrix effects.
  • Confirm that the epitope recognized by your ELISA antibodies is present and accessible on the recombinant protein, especially if it is expressed in a different system (e.g., E. coli vs. mammalian cells), as post-translational modifications may differ.
  • If your ELISA kit is validated with a specific recombinant standard, using a different preparation may require re-validation for accuracy and parallelism.

• Research use only: Most recombinant CCL17/TARC proteins and ELISA kits are for research use only and not for diagnostic purposes.

In summary:
You can use recombinant human CCL17/TARC as a standard for ELISA quantification, following standardization and validation procedures to ensure assay accuracy and reproducibility.

Recombinant Human CCL17/TARC has been validated for several key applications in published research:

Functional and Bioassay Applications

T cell chemotaxis and recruitment represents the primary functional application. Recombinant CCL17 has been demonstrated to be chemotactic for T cell lines, particularly Th2 cells, making it valuable for studying T lymphocyte migration and trafficking. The protein specifically attracts T cells through binding to the CCR4 receptor on T cell surfaces, which is critical for understanding adaptive immune responses.

Dose-dependent chemoattraction assays have been established using transfected cell lines expressing human CCR4, allowing researchers to quantify the functional activity of recombinant CCL17 preparations.

Immunological Research Applications

The protein has been utilized in ex vivo neutralization studies to assess the effects of blocking TSLP-mediated CCL17 release from primary human dendritic cells and to evaluate impacts on activated CD4+ T cell proliferation.

Disease modeling represents another validated application, with recombinant CCL17 employed in animal models of inflammatory conditions including asthma and psoriasis to understand chemokine-driven immune responses.

Analytical and Detection Applications

ELISA (enzyme-linked immunosorbent assay) has been validated for quantitative detection of natural and recombinant human CCL17 in biological samples including serum, plasma, and cell culture supernatants.

Western blotting, mass spectrometry, and HPLC have been established as analytical methods for characterizing recombinant CCL17 preparations.

Clinical and Diagnostic Research

Recombinant CCL17 has been investigated as a laboratory marker for disease diagnosis and activity assessment, particularly in atopic dermatitis and other inflammatory conditions.

To reconstitute and prepare Recombinant Human CCL17/TARC protein for cell culture experiments, briefly centrifuge the vial before opening to ensure all lyophilized material is at the bottom. Reconstitute the protein in sterile distilled water or PBS to a final concentration typically between 0.1–1.0 mg/mL, depending on your experimental requirements.

Key steps and best practices:

• Centrifuge the vial before opening to collect all powder at the bottom.
• Add sterile distilled water or PBS gently down the side of the vial to avoid foaming or denaturation.
• Do not vortex or mix vigorously; instead, gently pipette up and down or allow the protein to dissolve passively at room temperature.
• For carrier-free preparations, use only sterile PBS or water. For carrier-added formulations, reconstitute in PBS containing at least 0.1% low endotoxin BSA or heat-inactivated fetal calf serum to enhance stability.
• After reconstitution, aliquot the solution to avoid repeated freeze-thaw cycles and store at −20°C for long-term use. For short-term use (up to one week), store at 2–8°C.
• For cell culture, further dilute the reconstituted stock in tissue culture-grade buffer or medium, ideally supplemented with low endotoxin BSA or serum to minimize protein adsorption and loss.

Example protocol:

1. Centrifuge the vial briefly.
2. Add sterile distilled water or PBS to achieve 0.1–1.0 mg/mL (e.g., add 100 μL to a 100 μg vial for 1 mg/mL stock).
3. Gently mix by pipetting; do not vortex.
4. Allow the protein to dissolve completely (may take several minutes).
5. Aliquot and store as described above.
6. For cell culture, dilute the stock solution in your assay buffer or medium immediately before use.

Additional notes:

• Avoid reconstituting at concentrations above 1 mg/mL to prevent aggregation.
• Always use endotoxin-free reagents and sterile technique to prevent contamination and ensure cell viability.
• If using for sensitive cell types, confirm the absence of carrier proteins or additives that may affect your assay.

These steps will help maintain the biological activity and stability of CCL17/TARC for reliable cell culture experiments.