GS Xceed® Gene Expression System | GS® CHO

>35 years' experience

We have extensive experience in developing and delivering with market-leading mammalian protein expression platforms.

Scalable and regulatory-compliant processes

We can help you develop robust, efficient, scalable and regulatory-compliant processes to equip you for ultimate commercial success.

>100 molecules

In clinic manufactured with our expression platforms.

A proven expression system, now enhanced with next-generation vector technology

The GS® Expression System is a widely adopted platform for the development and manufacture of recombinant proteins, based on glutamine synthetase–mediated selection in CHO cells. GS Ori-Go™ vectors extend the capabilities of this platform through advanced promoter engineering and optimized vector elements, improving expression control and selection stringency.

These enhancements result in highly stable, high-performing bulk pools that can be progressed directly into cell line development workflows, reducing process complexity and enabling faster timelines to research cell bank generation.

Access a range of mammalian protein expression technologies

Benefit from access to our proven and scalable CHO-based gene expression system to create a diverse range of biologic drugs. Market demand continues to rise for more potent and effective therapeutics and biologic pipelines are moving from standard antibody formats to next-generation biologics.

Proprietary technology and expertise are at the core of our expression platforms. This makes us the ideal partner to provide you with a robust and versatile expression system to optimize your production. License our technology into your lab with the Lonza in your lab® offering or rely on us to do it for you.

Contact our technical experts today.

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Accelerate speed with Early Development Services (EDS)

With the GS® Expression System in Early Development Services (EDS), your program can gain rapid, non GMP protein and early data. With the data you’ll be informed of the expression behavior, manufacturability and immunosafety of your lead candidate. These early readouts reduce technical risk and streamline the path to cell line development and subsequent IND/first in human activities.

Testimonials from our clients

The introduction of Lonza's GS System® technology has strengthened our mammalian expression platform and improved screening efficiency. Lonza's GS Gene Expression System® platform is an easy-to-use mammalian cell protein expression system. Utilizing this system, AcroImmune Biopharmaceutical Co., Ltd (AcroImmune) obtained approval to conduct clinical trials in the U.S. and China for AI-081 bispecific antibody, an innovative drug candidate independently developed by AcroImmune targeting oncology indications. Looking ahead, AcroImmune also plans to explore the potential application of the GS System® technology in multiple innovative drug candidates within its proprietary R&D pipeline.

— Minyang Gu, AcroImmune Biopharmaceutical. China

Utilizing Lonza’s GS Gene Expression System® technology has streamlined biotherapeutic development for Clayton Medical Research Foundation.  The mission of Clayton is to support innovative medical research and facilitate moving discoveries from the lab bench to the clinic. Lonza’s advanced CHO-based protein expression platform has successfully enabled Clayton’s researchers to produce a difficult-to-express protein. The Clayton team will now take the next steps in further development of this unique molecule and pave the way to the clinic.  Applying Lonza’s GS Xceed® technology, an industrially relevant platform, in early preclinical development in the hands of innovative scientists has proven to be a great cooperation model.  We look forward to continuing our cooperation and making the impossible possible.

— Alexandra Richardson, Executive Board Director, Clayton Medical Research Foundation. Texas, USA

At CuraTeQ Biologics, using the Lonza GS Gene Expression System® technology has been a critical enabler of our success. Thanks to the GS® platform, we’ve not only established strong expression, consistent yields, and scalability across our oncology and immunology biosimilar programs — but we’ve also achieved key regulatory milestones: EMA (EC) approval for Dazublys®, our oncology trastuzumab biosimilar, and MHRA approval for Bevqolva®, our oncology bevacizumab biosimilar. Lonza’s GS® platform underpins our ability to confidently execute both current and future programs with the quality and reproducibility required for global regulatory standards.

— Satakarni Makkapati, Chief Executive Officer, CuraTeQ Biologics. India

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Ask the Experts in Expression

Frequently Asked Questions

What makes the GS® CHO cell line different from standard CHO cells?

The GS® CHO platform utilizes the glutamine synthetase enzymatic pathway as a dominant selectable marker. By employing host cell lines that lack endogenous glutamine synthetase activity, the system creates a stringent metabolic requirement for glutamine. Only cells that successfully integrate the expression vector, which carries both the gene of interest and the glutamine synthetase functional gene, can survive in glutamine-free media. This high-stringency selection promotes the development of stable, high-titer cell lines and minimizes the risk of clonal variations, ensuring superior performance in large-scale mammalian protein expression workflows compared to standard CHO cells.

How does the GS system® platform accelerate timelines for mammalian protein expression?

Speed is built into the genetic selection. Because the GS® CHO platform is so efficient at identifying high-performing cells early, we can move from DNA transfection to a stable, high-yielding cell line in weeks rather than months. This fast-track capability is designed to help you reach Investigational New Drug (IND) filing much sooner.

Can the GS Xceed® system handle difficult-to-express proteins?

While standard mammalian protein expression can struggle with complex new formats like bispecific antibodies or fusion proteins, our GS Gene Expression System® platform includes advanced technologies, like GS piggyBac® technology. These tools specifically target the most active parts of the cell’s genome, forcing the cells to produce even the most stubborn proteins at high titers.

What advantages does the GS® CHO platform offer for scaling mammalian protein expression to commercial manufacturing?

Because the GS® CHO expression system is already widely used in regulatory‑approved biologics, it provides a predictable, scalable path from early development through commercial production. This ensures high stability, strong genetic control and efficient scale‑up, reducing process risks at later stages.

Is the GS Xceed® Gene Expression System suitable for developing next‑generation biologics beyond standard mAbs?

Yes. The GS Gene Expression System® platform is engineered to support complex biologic molecules, including bispecifics, fusion proteins and other emerging modalities. Tools like GS piggyBac® technology help maximize expression and reduce mispairing, making it ideal for evolving biologic pipelines.

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GS piggyBac® Transposon Technology

The GS piggyBac® system supports stable gene integration and efficient cell line engineering.

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GS Effex® Cell Line

The GS Effex® cell line delivers fully fucose-free molecules with higher potency while maintaining titers and stability.

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GS Discovery® Transient Expression

GS Discovery® platform uses optimized transient expression processes to enable early stage expression of therapeutic molecules.

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bYlok® Bispecific Pairing Technology

Lonza’s bYlok® platform technology was developed to help solve mispairing in bispecific antibodies.