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CHO Cells Protein Expression and Purification Services

CD Biosynsis offers premium CHO (Chinese Hamster Ovary) Cells Protein Expression and Purification Services, utilizing the industry-standard mammalian host for the high-quality, large-scale production of complex biotherapeutics. CHO cells are the established system for producing monoclonal antibodies (mAbs), therapeutic proteins, and biosimilars that require accurate mammalian post-translational modifications (PTMs), correct disulfide bond formation, and complex protein assembly. Our comprehensive service spans from gene synthesis and vector construction (plasmid or stable integration) to high-cell-density fed-batch fermentation and multi-step chromatography for high-purity protein isolation. We guarantee the production of functional, correctly folded proteins, ensuring clients receive high-quality material for downstream applications in clinical trials, drug screening, and structural biology.

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Service Overview Expression & Purification Tools Production Workflow Key Advantages FAQs

Producing Complex, Functional Biotherapeutics in the Mammalian Host

The key advantage of using CHO cells is their ability to perform human-compatible protein processing. This includes the endoplasmic reticulum (ER) and Golgi apparatus, which are essential for processing, folding, and secreting proteins that require complex N- and O-linked glycosylation, disulfide bridges, and native assembly for functionality. Our platform leverages optimized expression vectors, advanced cell line engineering techniques (e.g., anti-apoptosis knockouts), tailored high-cell-density fed-batch culture protocols, and efficient purification strategies to maximize soluble, active protein yield. This focus on mammalian fidelity ensures the final purified protein meets stringent regulatory and quality standards.

Expression System and Purification Techniques (CHO Cells Focus)

Expression System Optimization High-Resolution Purification Target Protein Types

Expression System Optimization (Leveraging Mammalian Biology)

Maximizing Titer and Stability

Codon Optimization

Rational design and optimization of the target gene sequence to match CHO cell codon usage and GC content, significantly enhancing translation efficiency and total protein titer.

Stable Cell Line Generation

Creation of stable, high-expressing clones through random integration followed by selection/amplification (DHFR/GS systems) or targeted CRISPR-mediated knock-in into genomic safe harbor sites.

Fed-Batch Fermentation

Optimization of media and feeding strategies for high-cell-density culture (HCDC), maximizing the specific productivity (Qp) and culture longevity of the CHO cell line.

High-Resolution Purification (Focused on Biotherapeutic Quality)

Achieving High Purity and Functionality

Affinity Chromatography (AC)

Primary capture using highly specific methods (e.g., Protein A/G for mAbs, or His-tag/Strep-tag) from the large-volume culture supernatant to achieve high initial purity.

Ion Exchange Chromatography (IEX)

Used as a polishing step to remove residual Host Cell Proteins (HCPs) and address product charge variants (e.g., deamidation, aggregation), crucial for biotherapeutic homogeneity.

Viral Inactivation/Filtration

Mandatory steps (low pH incubation, specific filtration) incorporated into the purification train to meet regulatory requirements for the safety of mammalian-expressed biopharmaceuticals.

Target Protein Types (CHO Specific Capabilities)

Versatility in Production

Monoclonal Antibodies (mAbs)

Standard production of IgGs, IgMs, bispecific antibodies, and antibody fragments, ensuring native assembly and the desired human-like N-glycan profile.

Complex Glycoproteins

Expression of therapeutic proteins (e.g., erythropoietin, clotting factors) that require complex, native N-linked and O-linked glycosylation patterns for biological activity and half-life.

Recombinant Vaccines/Antigens

High-yield production of multi-subunit protein antigens and viral surface proteins that require correct disulfide linkage and folding for immunogenicity.

CHO Cells Protein Production Workflow

A systematic process from gene design to final quality-controlled biotherapeutic product.

1. Gene & Vector Design

2. Stable Cell Line Generation

3. Bioreactor Culture & Harvest

4. Multi-Step Purification & QC

Codon optimize gene for CHO cell expression; design purification tags and required regulatory elements.

Clone gene into DHFR/GS selection vector or CRISPR knock-in cassette for chromosomal integration.

Perform small-scale transient expression to confirm protein quality and yield.

Transfect CHO host cells and select/amplify clones (e.g., Methotrexate for DHFR or Puromycin).

Screen clones using HTS (ELISA/FACS) to identify High-Producer clones; establish master cell bank (MCB).

Select the final clonal cell line based on titer, product quality, and genetic stability.

  • Scale-Up: Transfer MCB to fed-batch bioreactor for High-Cell-Density Culture (HCDC).
  • Induction: Optimize temperature, pH, and feeding strategy (e.g., glucose, glutamine) for maximal production phase.
  • Harvest: Clarify culture supernatant containing the secreted therapeutic protein.

Purification: Execute multi-step chromatography (Affinity, IEX, SEC) and necessary viral inactivation/filtration steps.

QC: Purity analysis (SDS-PAGE/CE-SDS), identity (Mass Spec), Glycan Analysis, and Functional Assay.

Delivery of purified protein, Certificate of Analysis (CoA), and documentation of all upstream/downstream protocols.

Superiority in CHO Cells Protein Production

Regulatory Acceptance

CHO cells are the most widely accepted mammalian production system by global regulatory bodies (FDA/EMA) for manufacturing commercial biopharmaceuticals.

Accurate Human PTMs

The host performs correct protein folding, disulfide bond formation, and, crucially, human-compatible glycosylation essential for drug efficacy and safety.

Scalability & Titer

Our optimized HCDC fed-batch protocols and high-producer cell lines achieve superior volumetric productivity, ensuring cost-effective scalability for commercial supply.

Integrated Quality Control

Purification protocols include necessary viral clearance and high-resolution chromatography steps to achieve high purity and address critical quality attributes (CQAs) like aggregation and charge variants.

FAQs About CHO Cells Protein Expression Services

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1. What types of proteins are best expressed in CHO cells?

CHO cells are ideal for complex glycoproteins, especially those requiring proper disulfide bonding, dimerization, and human-like N-linked glycosylation, such as monoclonal antibodies (mAbs), fusion proteins, and hormones.

2. How is a stable, high-producing cell line established?

We use vector integration systems (DHFR/GS) or CRISPR-Cas9 targeted knock-in, followed by antibiotic selection and Methotrexate/MSX gene amplification, and finally, single-cell cloning using FACS to isolate the highest-producer clones.

3. Do you offer services to optimize the protein's glycan profile?

Yes. We use advanced gene editing (CRISPR/Base Editing) to modify host cell glycosylation genes (e.g., FUT8 KO) or introduce heterologous human glycosylation enzymes, precisely tailoring the glycan structure for optimal therapeutic efficacy.

4. What is the role of the DHFR/GS system in stable cell line generation?

The DHFR (Dihydrofolate Reductase) and GS (Glutamine Synthetase) systems allow for metabolic selection and gene amplification. By treating the cells with Methotrexate or MSX, the cells are forced to increase the copy number of the integrated therapeutic gene, significantly boosting titer.

5. How is the final purified product's quality verified?

Final QC includes CE-SDS or SDS-PAGE for purity and aggregation, Mass Spectrometry (MS) for identity and molecular weight, isoelectric focusing (IEF) for charge profile, and full glycan analysis.

6. What fermentation culture mode is used for large-scale production?

We utilize optimized fed-batch culture protocols in stirred-tank bioreactors. This High-Cell-Density Culture (HCDC) approach provides the necessary scalability, titer, and control required for industrial GMP manufacturing.

7. What is included in the documentation package?

We provide a comprehensive Certificate of Analysis (CoA) for the purified protein, stability data for the Master Cell Bank (MCB), and detailed protocols for the upstream (cell culture) and downstream (purification) processes.

8. How do you ensure the genetic stability of the cell line?

Stability is ensured by selecting clones with integration into defined genomic safe harbor loci (via CRISPR/HDR) and verifying stable productivity over many generations (typically 60-90 population doublings).