Nebulabio provide comprehensive, end-to-end Fc Fusion Protein production services, from construct design and molecular engineering to large-scale expression, purification, and characterization. Fc fusion technology represents a powerful strategy to enhance the pharmacokinetic properties, stability, and functionality of therapeutic proteins, peptides, and other bioactive domains. Our specialized service is designed for biopharmaceutical companies and research institutions developing next-generation biologics for therapeutic, diagnostic, and research applications. Leveraging our expertise in mammalian expression systems, particularly CHO cells, we deliver high-quality, homogeneous Fc fusion proteins with consistent post-translational modifications. We support all stages of development, from initial design and small-scale feasibility studies to pilot-scale GLP-like production for preclinical studies, ensuring your candidate molecule is produced with the quality and yield required to advance your program.

☞Introduction to Fc Fusion Protein

An Fc Fusion Protein is a genetically engineered biomolecule created by fusing the fragment crystallizable (Fc) region of an immunoglobulin (typically IgG) to a protein or peptide of interest (the "effector" domain). This elegant design confers several advantageous properties derived from the native functions of antibodies:

● Extended Serum Half-life: The primary benefit. The Fc region binds to the neonatal Fc receptor (FcRn), which protects the fusion protein from lysosomal degradation and recycles it back into circulation. This dramatically increases its plasma residence time compared to the unfused effector domain, reducing dosing frequency.

● Enhanced Stability & Solubility: The Fc domain often improves the physical stability and solubility of the fused partner, which is particularly valuable for proteins or peptides that are otherwise prone to aggregation or have poor pharmacokinetic profiles.

● Effector Functions (Optional): Depending on the chosen IgG isotype (e.g., IgG1 vs. IgG4), the Fc domain can retain effector functions such as Antibody-Dependent Cellular Cytotoxicity (ADCC) or Complement-Dependent Cytotoxicity (CDC). These can be engineered in or out based on the therapeutic goal (e.g., desired for targeting immune cells, silenced for cytokine blockers).

● Simplified Purification: The Fc tag allows for highly efficient, one-step purification using Protein A or Protein G affinity chromatography, ensuring high purity and recovery.

● Dimerization: The natural dimeric structure of the Fc domain can promote the dimerization of the fused effector domain, which is essential for the activity of some receptors or ligands (e.g., TNF inhibitors).

Common fusion partners include cytokines, growth factors, receptor extracellular domains (traps), enzymes, and single-chain variable fragments (scFvs), creating a versatile platform for drug design.

Figure1. Antibody features that contribute to PK properties.

☞Applications of Fc Fusion Proteins

Fc fusion proteins are a validated and growing class of biologics with diverse applications:

☞Fc Fusion Protein Production Process

Our production process is optimized for the unique characteristics of Fc fusion molecules, ensuring proper folding, dimerization, and glycosylation.

①Gene Design & Vector Construction: The DNA sequence encoding the effector domain is fused in-frame to the Fc region of a chosen human IgG isotype (IgG1, IgG2, IgG4, with silencing mutations as needed). The construct is codon-optimized for CHO cells and cloned into a high-expression mammalian vector.

②Cell Line Development: The expression vector is transfected into a proprietary CHO host cell line. Stable pools are generated under selection, followed by single-cell cloning to isolate high-producing, stable clones. A Master Cell Bank (MCB) is created from the lead clone.

③Upstream Process Development: A fed-batch bioreactor process is developed and optimized for the specific clone. Key parameters like media, feed strategy, pH, dissolved oxygen, and temperature are fine-tuned to maximize titer while maintaining product quality (e.g., glycan profile, aggregation level).

④Harvest & Clarification: The cell culture broth is harvested, and cells/debris are removed via depth filtration or centrifugation.

⑤Downstream Purification: A typical platform process includes:

● Capture: Protein A affinity chromatography, leveraging the Fc tag for highly specific and efficient capture.

● Viral Inactivation: Low-pH hold step.

● Polishing: One or two chromatography steps (e.g., Cation Exchange, Anion Exchange, or Mixed-Mode) to remove aggregates, host cell proteins, DNA, and leached Protein A.

● Viral Filtration: Nanofiltration for viral clearance.

● Ultrafiltration/Diafiltration (UF/DF): Final concentration and buffer exchange into the desired formulation buffer.

⑥Analytical Characterization: The purified product undergoes extensive analysis: SEC-HPLC for purity/aggregates, CE-SDS for reduced/non-reduced purity, MS for mass confirmation, HPLC for glycan profiling, and functional potency assays.

☞Nebulabio Service Process

Our collaborative and transparent service process guides you from concept to purified material.

 Process Steps Description: 

● Consultation & Design: We collaborate to design the optimal fusion architecture (linker, Fc isotype, effector domain boundaries) based on your target product profile.

● Cell Line Development: We execute stable CHO cell line generation, including transfection, selection, and single-cell cloning to deliver a high-yielding, validated Master Cell Bank.

● Process Development: We develop and lock down the upstream (bioreactor) and downstream (purification) processes, establishing critical quality attributes (CQAs).

● Scale-up Production: The developed process is executed at the agreed scale (from bench-top to pilot-scale bioreactors) to produce your target batch size.

● Purification & Analytics: The product is purified through the optimized downstream train, formulated, and subjected to a full panel of analytical tests for comprehensive characterization.

● Delivery: You receive the purified, bottled Fc fusion protein, along with a detailed Certificate of Analysis (CofA) and a comprehensive technical development report.

☞Why Choose Nebulabio?

● Specialized Fc Fusion Expertise: We have deep, platform-level expertise in the molecular design, expression challenges, and purification specifics of Fc fusion proteins, ensuring higher success rates.

● CHO-Dedicated Platform for Optimal Quality: Our focus on CHO expression ensures your fusion protein receives human-compatible, consistent glycosylation critical for half-life and stability, directly applicable to therapeutic development.

● Integrated Development from DNA to Drug Substance: We offer a seamless, in-house service covering construct design, cell line development, process optimization, and cGMP-ready production, reducing complexity and timelines.

● Focus on Functional Activity: Our processes are designed not just for high yield and purity, but to preserve the biological activity of both the effector domain and the Fc region (or its engineered silence).

● Scalable & Tech-Transfer Ready Processes: Our development work is performed with scalability and regulatory compliance in mind, facilitating smooth future transfer to large-scale GMP manufacturing.

● Dedicated Project Partnership: You are assigned a dedicated project team providing regular updates, transparent data sharing, and scientific collaboration throughout the project lifecycle.

☞Accelerate Your Fc Fusion Biologic Development

Partner with our experienced team to leverage a streamlined, expert-driven platform for your Fc fusion protein production needs. From innovative design to high-quality material for preclinical studies, we provide the scientific excellence and reliable execution to advance your biologic candidate.

Contact Nebulabio to discuss your Fc fusion project and receive a detailed proposal.

For more information, please contact us at info@nebulabio.cn or +86-15801534258.