Recombinant Human G-CSF

Recombinant Human Granulocyte Colony-Stimulating Factor (G-CSF) is a valuable tool for a wide range of research applications due to its well-characterized biological effects and versatility. Here are several key reasons why you should consider using recombinant human G-CSF in your research:

1. Promotes Neutrophil Lineage Development

Recombinant human G-CSF specifically stimulates the proliferation, differentiation, and survival of neutrophil progenitor cells. This makes it ideal for studies focused on hematopoiesis, myeloid cell biology, and immune cell development.

2. Accelerates Neutrophil Recovery

G-CSF accelerates the replenishment of neutrophils following myelosuppressive treatments (e.g., chemotherapy or radiation). This property is useful for modeling recovery from neutropenia and studying host defense mechanisms in experimental systems.

3. Supports Functional Assays

G-CSF enhances the functional activity of mature neutrophils, including chemotaxis, phagocytosis, and microbial killing. It can be used in functional assays to investigate neutrophil responses to infection, inflammation, or immune modulation.

4. Enables Cell Culture and Differentiation Studies

Recombinant human G-CSF is optimized for use in cell culture systems, supporting the expansion and differentiation of hematopoietic progenitor cells. It is widely used in protocols for generating neutrophils and other myeloid cells from primary or stem cell sources.

5. Facilitates Preclinical and Translational Research

G-CSF has been extensively studied in both animal models and clinical settings, providing a strong foundation for translational research. Its use in preclinical studies can help bridge findings from bench to bedside, particularly in areas such as immunotherapy, infection, and regenerative medicine.

6. Low Toxicity and Well-Characterized Safety Profile

Recombinant human G-CSF has a favorable safety profile, making it suitable for repeated administration in experimental models. Its low toxicity allows for long-term studies and chronic dosing regimens.

7. Versatile Applications

Beyond hematopoiesis, G-CSF has been explored in diverse research areas, including:

• Modulation of immune responses
• Host defense against bacterial and fungal infections
• Support of stem cell mobilization
• Investigation of fertility and reproductive biology

8. Availability of Long-Acting and Modified Forms

Advanced recombinant G-CSF variants (e.g., fusion proteins, PEGylated forms) offer extended half-life and improved pharmacokinetics, enabling less frequent dosing and more sustained effects in experimental models.

In summary, recombinant human G-CSF is a powerful and flexible reagent for research involving neutrophil biology, immune function, hematopoiesis, and host defense. Its well-documented effects, ease of use, and broad applicability make it an essential tool for both basic and applied research.

Yes, you can use Recombinant Human G-CSF as a standard for quantification or calibration in your ELISA assays, provided that the recombinant protein is suitable for your specific ELISA kit and experimental conditions.

Key Points to Consider:

• Compatibility: Most ELISA kits for human G-CSF are designed to detect both natural and recombinant forms of the protein. For example, several kits (such as those from R&D Systems, Eagle Biosciences, and ACROBiosystems) explicitly state that their assays recognize both natural and recombinant human G-CSF, and the standard provided in the kit is often recombinant human G-CSF.

• Source and Formulation: Recombinant Human G-CSF is typically produced in E. coli and consists of amino acids 31–204 (with an N-terminal methionine). This is the same form used as the standard in many commercial ELISA kits. If your recombinant G-CSF matches this sequence and is purified appropriately, it should be suitable for use as a standard.

• Activity and Purity: Ensure that your recombinant G-CSF is biologically active and highly purified. Some suppliers provide quality control data, such as bioactivity assays (e.g., cell proliferation assays) and purity assessments (e.g., SDS-PAGE), which can help confirm its suitability.

• Concentration and Dilution: Prepare a standard curve using serial dilutions of your recombinant G-CSF in the same matrix as your samples (e.g., buffer, serum, or plasma). This will allow you to accurately quantify the concentration of G-CSF in your samples.

• Kit Instructions: Always refer to the manufacturer's instructions for your ELISA kit. Some kits may recommend using their provided standard for optimal performance, but if you choose to use your own recombinant G-CSF, ensure it is compatible with the detection antibodies and assay conditions.

Example from Literature:

• R&D Systems: Their ELISA kits use E. coli-expressed recombinant human G-CSF as the standard, and they have shown that the kit can accurately quantitate both recombinant and natural human G-CSF.
• Eagle Biosciences: Their kit recognizes both natural and recombinant human G-CSF, and the standard provided is recombinant.

Conclusion:

If your Recombinant Human G-CSF is of high purity, biologically active, and matches the sequence used in the ELISA kit, it can be used as a standard for quantification or calibration in your ELISA assays. Always validate the standard curve and ensure compatibility with your specific kit and experimental setup.

Recombinant human G-CSF has been validated for numerous clinical and research applications across multiple therapeutic domains:

Hematological and Oncological Applications

The primary and most extensively validated application is chemotherapy-induced neutropenia (CIN) prevention and management. Recombinant human G-CSF enables optimal chemotherapy delivery by reducing febrile neutropenia risks, allowing patients to maintain appropriate chemotherapy dosing without undue reductions or delays. The factor rapidly increases neutrophil production, reducing both the maturation and release times of bone marrow neutrophils from the normal 4-5 days to 1-2 days.

Beyond chemotherapy support, recombinant human G-CSF has been validated for treating severe chronic neutropenia and acquired neutropenia, including conditions such as aplastic anemia and myelodysplastic syndromes. The protein is also widely employed for mobilization of CD34+ hematopoietic stem cells from bone marrow to peripheral blood for use in hematopoietic stem cell transplantation.

Immunomodulatory and Inflammatory Applications

Research has demonstrated that recombinant human G-CSF possesses anti-inflammatory and immune-regulatory properties beyond its hematological effects. The factor induces peripheral regulatory T-cells and myeloid-derived suppressor cells, which help regulate immune responses to infection and inflammation.

Clinical investigation has extended to infectious disease contexts, including a randomized trial in hospitalized COVID-19 patients with lymphopenia, where treatment increased lymphocyte and leukocyte cell counts and was associated with reduced progression to invasive ventilation and lower 21-day mortality in patients with severe lymphopenia.

Neuroprotective Applications

Recombinant human G-CSF has been validated as a therapeutic candidate for stroke, demonstrating anti-inflammatory and neuroprotective properties. Animal studies confirm its ability to decrease pro-inflammatory cytokine release (TNF, IFN-γ, IL-6) while enhancing anti-inflammatory cytokine production such as IL-4.

Additional Validated Applications

The protein exhibits anti-apoptotic and pro-angiogenic properties, and has been investigated in contexts including granulocyte transfusion therapy and immunocompetent patient populations. Research has also explored its potential role in reproductive medicine and other specialized clinical settings.

To reconstitute and prepare Recombinant Human G-CSF for cell culture experiments, dissolve the lyophilized protein in sterile buffer to a concentration suitable for your application, typically between 0.05–1.0 mg/mL, using sterile water or PBS with carrier protein (such as 0.1% BSA) to enhance stability and prevent adsorption.

Step-by-step protocol:

1. Centrifuge the vial briefly before opening to ensure all lyophilized material is at the bottom.
2. Add sterile buffer:
   • For most applications, use sterile deionized/distilled water or sterile PBS (pH 7.2–7.4).
   • If recommended, include 0.1% BSA (bovine or human serum albumin) to stabilize the protein and prevent loss from adsorption to plasticware.
3. Reconstitution concentration:
   • Common working concentrations are 0.1–1.0 mg/mL for stock solutions.
   • Some protocols recommend 50 μg/mL in PBS with 0.1% BSA for immediate use.
4. Mix gently by pipetting up and down or gentle vortexing. Avoid vigorous agitation to prevent protein denaturation.
5. Allow the solution to sit at room temperature for several minutes to ensure complete dissolution.
6. Aliquot the stock solution into small volumes to avoid repeated freeze-thaw cycles.
7. Storage:
   • Store aliquots at ≤–20°C or –80°C for long-term stability.
   • Avoid repeated freeze-thaw cycles, which can degrade the protein.
   • For short-term use, keep at 4°C for up to a week, if recommended by the manufacturer.

Additional notes:

• Always consult the specific product datasheet for any unique formulation or buffer requirements, as some preparations may contain additives (e.g., trehalose, acetic acid) that influence the choice of reconstitution buffer.
• For cell culture, ensure all reagents are endotoxin-free and sterile to prevent confounding effects on cells.
• After reconstitution, dilute the stock to the desired working concentration in your cell culture medium immediately before use.

Summary Table: Common Reconstitution Conditions

These guidelines ensure maximal activity and stability of recombinant human G-CSF for cell culture applications.