Recombinant Human IL-7

Recombinant Human IL-7 (rhIL-7) is widely used in research because it is a critical cytokine for T cell development, survival, and homeostasis, making it essential for studies involving immune reconstitution, immunotherapy, and lymphocyte biology.

Key reasons to use recombinant human IL-7 in research applications:

• T Cell Development and Expansion: IL-7 is indispensable for the development and maintenance of both naïve and memory T cells. Administration of rhIL-7 leads to robust proliferation and expansion of CD4⁺ and CD8⁺ T cells, increasing overall T cell numbers and rejuvenating the T cell compartment.
• Immune Reconstitution: rhIL-7 is particularly valuable in models of lymphopenia (e.g., after chemotherapy, hematopoietic stem cell transplantation, or in HIV infection), where it accelerates immune recovery and broadens the T cell receptor (TCR) repertoire, enhancing immune competence.
• Immunotherapy and Vaccine Research: IL-7 enhances the efficacy of cancer vaccines and adoptive T cell therapies by promoting the survival, proliferation, and function of tumor-specific T cells, and is used to optimize CAR T cell expansion and persistence.
• B Cell and Thymic Effects: IL-7 also supports early B cell development and increases thymic output, which can be important for studies on hematopoiesis and immune aging.
• Broad Immunomodulatory Effects: IL-7 modulates multiple immune cell subsets, promotes Th2 responses, increases antibody production, and enhances cytotoxicity of effector cells, making it a versatile tool for dissecting immune mechanisms.
• Safety and Translational Relevance: Clinical and preclinical studies show that rhIL-7 is generally well tolerated and bioactive, supporting its use in translational research and therapeutic development.

Typical research applications include:

• Studying T cell biology and homeostasis
• Modeling immune reconstitution after depletion
• Enhancing adoptive cell therapies (e.g., CAR T cells)
• Investigating mechanisms of immune aging or immunodeficiency
• Evaluating vaccine adjuvanticity and anti-tumor immunity

In summary, recombinant human IL-7 is a powerful tool for immunological research due to its unique and non-redundant roles in lymphocyte biology, immune restoration, and immunotherapy development.

Yes, recombinant human IL-7 can be used as a standard for quantification or calibration in ELISA assays, provided it is properly validated and matched to the assay system. Recombinant IL-7 is commonly used as a standard in commercial ELISA kits and is recognized by antibodies that detect both natural and recombinant forms of IL-7.

Key considerations and supporting details:

• Assay Calibration: ELISA kits for human IL-7 are typically calibrated against highly purified recombinant human IL-7, often expressed in E. coli. These standards are used to generate the standard curve for quantification of IL-7 in biological samples.

• Parallelism and Accuracy: Studies and kit documentation show that standard curves generated with recombinant IL-7 are parallel to those obtained with natural IL-7, indicating that recombinant IL-7 is suitable for accurate quantification.

• Specificity: Most ELISA kits specify that their antibodies recognize both natural and recombinant human IL-7, ensuring that the recombinant standard is appropriate for calibration.

• Validation: It is important to confirm that the recombinant IL-7 standard is compatible with your specific ELISA system. This includes verifying that the standard curve is linear and that recovery and parallelism tests meet assay requirements.

• Formulation: For ELISA calibration, use recombinant IL-7 formulated for analytical use (carrier-free or with appropriate stabilizers), as some formulations intended for cell culture may contain additives (e.g., BSA) that could interfere with assay performance.

• Reference Standards: Some kits compare their recombinant IL-7 standard to international reference reagents (e.g., NIBSC/WHO 90/530), allowing conversion between units if needed.

Best Practices:

• Prepare a dilution series of recombinant IL-7 in the same buffer or diluent used for your samples to ensure matrix compatibility.
• Validate the standard curve for linearity, accuracy, and parallelism with your sample type.
• Use the same recombinant IL-7 lot for all calibrations within a study to minimize variability.

Limitations:

• Recombinant standards may differ slightly in glycosylation or folding compared to natural IL-7, but this is generally not significant for immunoassay quantification as long as antibody recognition is confirmed.
• Always refer to your ELISA kit’s instructions and validation data to ensure compatibility.

Summary Table: Recombinant Human IL-7 as ELISA Standard

In conclusion, recombinant human IL-7 is appropriate for use as a standard in ELISA quantification and calibration, provided it is validated for your specific assay system and sample matrix.

Recombinant Human IL-7 has been validated for a broad range of applications in published research, primarily focused on immunology, hematopoiesis, and clinical immunotherapy.

Key validated applications include:

• Immune Reconstitution and Enhancement:
  Recombinant human IL-7 has been used to restore and enhance T-cell populations in conditions of immune deficiency, such as after chemotherapy, hematopoietic stem cell transplantation, HIV infection, and age-related immunosenescence. It increases peripheral CD3⁺, CD4⁺, and CD8⁺ lymphocytes, rejuvenates the circulating T cell profile, and promotes polyclonal proliferation of pre-B cells in bone marrow.

• Cancer Immunotherapy:
  IL-7 has been applied to augment anti-tumor immune responses, both by direct administration and as a component of engineered cell therapies (e.g., CAR-T cells). It improves T-cell recovery post-transplant and prolongs tumor-free survival in preclinical models. In clinical studies, it has been used to support immune function during salvage chemotherapy for recurrent glioblastoma.

• HIV/AIDS Research:
  Clinical trials have validated rhIL-7 for expanding CD4 T-cell pools, broadening T-cell receptor diversity, and improving thymopoiesis in HIV-infected patients on antiretroviral therapy.

• In Vitro T Cell Expansion and Differentiation:
  Recombinant IL-7 is widely used for in vitro expansion, priming, and differentiation of T cells and invariant natural killer T (iNKT) cells, as well as for investigating IL-7-mediated signaling pathways.

• Hematopoietic Stem and Progenitor Cell Research:
  IL-7 stimulates development and differentiation of lymphoid progenitors, T cells, and B cells, and is used in protocols for expansion and differentiation of hematopoietic stem and progenitor cells.

• ELISA Standard:
  Recombinant human IL-7 is validated as a quantitative standard for measuring IL-7 protein levels in sandwich ELISA assays.

• Sepsis and Infectious Disease:
  IL-7 has shown improved survival in patients with sepsis, supporting its use in enhancing immune responses against secondary infections.

Additional validated uses include:

• Cellular Signaling Studies:
  Investigation of IL-7/IL-7R signaling pathways in various immune cell types.

• Adoptive Cell Transfer:
  Enhancement of cytotoxicity and persistence of transferred T cells in animal models.

• Autoimmune Disease Research:
  Modulation of IL-7R signaling is explored for delaying progression in autoimmune disease models.

These applications are supported by both preclinical and clinical studies, demonstrating the utility of recombinant human IL-7 in basic research, translational studies, and therapeutic interventions.

To reconstitute and prepare Recombinant Human IL-7 protein for cell culture experiments, briefly centrifuge the vial to collect the lyophilized powder at the bottom, then reconstitute in sterile water or PBS to a concentration of 0.1–1.0 mg/mL, and further dilute in a neutral buffer with carrier protein (such as BSA or HSA) to prevent adsorption and maintain stability.

Step-by-step protocol:

1. Centrifuge the vial briefly before opening to ensure all lyophilized material is at the bottom.
2. Reconstitution:
   • Add sterile, distilled water or sterile PBS (pH 7.2–7.4) to achieve a concentration between 0.1–1.0 mg/mL (commonly 0.1–0.5 mg/mL).
   • Gently pipette the solution down the sides of the vial to dissolve the protein. Do not vortex, as this may denature the protein.
   • Allow several minutes for complete dissolution.
3. Carrier protein addition (recommended):
   • For improved stability and to minimize adsorption, dilute the reconstituted IL-7 in a buffer containing 0.1% BSA or HSA (endotoxin-free, fatty acid-free).
   • Alternatively, use 5–10% FBS as a carrier in the working buffer.
4. Aliquoting and storage:
   • Divide the reconstituted protein into small aliquots to avoid repeated freeze-thaw cycles.
   • Store aliquots at ≤ –20°C (short-term) or –80°C (long-term).
5. Working concentration for cell culture:
   • For most in vitro applications, final working concentrations are typically in the range of 0.1–10 ng/mL.
   • Prepare fresh dilutions in cell culture medium immediately before use.

Additional notes:

• Always use endotoxin-free reagents and sterile technique to prevent contamination.
• If the protein will not be used immediately after reconstitution, the addition of carrier protein is especially important for stability.
• Avoid repeated freeze-thaw cycles, as these can reduce protein activity.

Summary Table:

These steps will ensure optimal activity and stability of recombinant human IL-7 for cell culture experiments.