Recombinant Human TNF sRI

Recombinant Human TNF sRI (soluble TNF receptor I) is used in research applications primarily as a high-affinity antagonist of TNF-α, enabling precise modulation and investigation of TNF-α-mediated signaling pathways, inflammation, and immune responses.

Key scientific reasons to use Recombinant Human TNF sRI:

• Neutralization of TNF-α Activity: TNF sRI binds free TNF-α with high affinity, preventing its interaction with cell-surface TNF receptors. This allows researchers to inhibit TNF-α-mediated cytotoxicity, apoptosis, and inflammatory signaling in vitro and in vivo.

• Modeling Anti-inflammatory Mechanisms: By blocking TNF-α, TNF sRI mimics the natural regulatory mechanism that controls excessive inflammation. This is valuable for studying the pathogenesis of autoimmune and inflammatory diseases, and for evaluating potential therapeutic interventions targeting TNF-α.

• Functional Assays and Controls: Recombinant TNF sRI is used in bioassays to confirm the specificity of TNF-α effects, serving as a negative control or as a tool to dissect TNF-α-dependent cellular responses.

• Disease Mechanism Studies: Soluble TNF receptors are found in biological fluids and are implicated in the regulation of immune responses in conditions such as ischemic stroke, cancer, and chronic inflammatory diseases. Recombinant TNF sRI enables mechanistic studies of these processes.

Technical considerations:

• Purity and Activity: Recombinant TNF sRI is typically purified to >95% and validated for biological activity, such as its ability to inhibit TNF-α-induced cytotoxicity in cell-based assays.

• Endotoxin Levels: Low endotoxin content (<0.01 EU/µg) is essential for cell culture and in vivo studies to avoid confounding immune activation.

Typical applications include:

• In vitro cell culture experiments to block TNF-α signaling.
• Animal models to study the effects of TNF-α inhibition.
• ELISA and other immunoassays as a standard or control for TNF-α neutralization.

In summary, Recombinant Human TNF sRI is a critical reagent for dissecting TNF-α biology, modeling anti-inflammatory strategies, and validating therapeutic approaches targeting TNF-α in diverse research contexts.

Recombinant Human TNF sRI (soluble TNF receptor I) is generally not suitable as a standard for quantifying TNF-α in ELISA assays designed to measure TNF-α, unless your assay specifically detects sTNF-RI. Standards for ELISA quantification must match the analyte being measured; using sTNF-RI as a standard for TNF-α quantification would yield inaccurate results.

Key points:

• ELISA standards must be the same molecule as the analyte. For TNF-α quantification, the standard should be recombinant human TNF-α, not sTNF-RI.
• sTNF-RI is a soluble receptor, not the cytokine TNF-α. It binds TNF-α and may be measured in assays designed for soluble receptors, but it is not interchangeable with TNF-α for calibration purposes.
• Assay specificity: Most TNF-α ELISA kits are validated to detect both natural and recombinant TNF-α, and they specifically test for lack of cross-reactivity with sTNF-RI and other related proteins.
• If your assay is designed to quantify sTNF-RI (soluble TNF receptor I), then recombinant human TNF sRI can be used as a standard for calibration. However, for TNF-α quantification, use recombinant TNF-α as the standard.

Best practice:

• Always use a standard that matches the analyte for accurate quantification.
• Confirm your ELISA’s specificity and validation data to ensure correct standard selection.

Summary Table:

Using the wrong standard will compromise assay accuracy and reliability. Always match your standard to the analyte your ELISA is designed to detect.

Recombinant Human TNF sRI (soluble TNF Receptor I) has been validated in published research primarily for applications involving the inhibition of TNF-α-mediated cytotoxicity, especially in cell-based bioassays. The most widely cited and validated application is:

• Inhibition of TNF-α-mediated cytotoxicity in L-929 mouse fibrosarcoma cells: This is a standard assay to confirm the biological activity of recombinant human TNF sRI, where its ability to block TNF-α-induced cell death is measured in the presence of actinomycin D.

Additional validated and potential applications, based on the broader use of recombinant TNF receptors and related proteins, include:

• Preclinical models of chronic inflammatory diseases: PEGylated forms of recombinant human soluble TNF-RI have been validated in rodent models of diseases such as rheumatoid arthritis, demonstrating efficacy in reducing inflammation and disease severity.
• Therapeutic drug development and screening: Recombinant TNF sRI is used to study TNF-α signaling pathways, screen for TNF-α inhibitors, and evaluate the neutralizing capacity of candidate drugs or antibodies targeting TNF-α.
• Pharmacokinetic and bioanalytical assays: While most ELISA-based assays use recombinant TNF-α as a capture reagent, soluble TNF receptors can also be used in ligand-binding assays to quantify TNF-α or to monitor the pharmacodynamics of anti-TNF therapies.

Summary of validated applications in published research:

• Cell-based bioassays for TNF-α inhibition (e.g., L-929 cytotoxicity assay).
• Preclinical efficacy studies in animal models of inflammation.
• Screening and characterization of anti-TNF drugs and biologics.

Key technical note: The L-929 cytotoxicity assay remains the gold standard for validating the biological activity of recombinant human TNF sRI, as it directly measures the protein’s ability to neutralize TNF-α in a functional context. Other applications, such as in vivo models and drug screening, are supported by the literature on soluble TNF receptors but may require additional validation depending on the specific experimental context.

To reconstitute and prepare Recombinant Human TNF sRI (soluble TNF Receptor I) protein for cell culture experiments, follow these general best practices based on standard protocols for lyophilized recombinant proteins and specific recommendations for TNF receptor proteins:

Reconstitution

1. Centrifuge the vial briefly before opening to ensure all lyophilized powder is at the bottom.
2. Reconstitute with sterile, cold PBS (phosphate-buffered saline) or as specified in the product datasheet. If the product contains BSA as a carrier, reconstitute with PBS containing at least 0.1% human or bovine serum albumin (BSA) to stabilize the protein. For carrier-free versions, sterile PBS alone is sufficient.
3. Recommended concentration: Reconstitute to a concentration of 100 µg/mL (or as specified by the manufacturer). For example, add 100 µL of buffer to a vial containing 10 µg of protein.
4. Gently mix the solution by swirling or inverting the vial. Avoid vigorous shaking to prevent foaming and protein denaturation.
5. Allow the vial to sit at room temperature for 15–30 minutes with gentle agitation to ensure complete dissolution.

Preparation for Cell Culture

1. Aliquot the reconstituted protein into small, single-use volumes to minimize freeze-thaw cycles.
2. Store aliquots at ≤ –20°C (preferably –80°C for long-term storage). Use a manual defrost freezer if possible.
3. Avoid repeated freeze-thaw cycles, as this can reduce protein activity.
4. For cell culture experiments, dilute the reconstituted protein in appropriate cell culture medium immediately before use. Ensure the final concentration of BSA (if used) is compatible with your cell type and experimental conditions.

Additional Notes

• Carrier protein: If the protein is supplied with BSA, it is generally recommended for cell culture applications as it enhances stability. For applications where BSA may interfere (e.g., certain biochemical assays), use a carrier-free version.
• Sterility: Always use sterile techniques when handling the protein to avoid contamination, especially for cell culture.
• Product-specific instructions: Always refer to the product datasheet or Certificate of Analysis (COA) for any specific reconstitution or storage recommendations.

By following these steps, you can ensure optimal activity and stability of Recombinant Human TNF sRI for your cell culture experiments.