GS Xceed® Gene Expression System

Reach Our GS Experts:

  • Introduction

    Since its introduction to the market in 1992, continuous advancements have been made to all components of Lonza’s industry-leading GS Gene Expression System®.  Improvements to the commercial platform process, host cell line and vectors resulted in the development of our GS Xceed® Gene Expression System.  The system produces high product titers in a robust, chemically defined, animal component-free (CDACF) environment and requires no MSX for stability.  The GS Xceed® System  had been designed with future manufacturability in mind. 

    The GS Xceed® System includes the CHOK1SV GS-KO™ (GS KnockOut™) host cell line, which is a derivative of Lonza’s suspension adapted CHOK1SV™ host cell line.  In this CHOK1SV-GS-KO™ cell line, both alleles of the endogenous glutamine synthetase gene have been “knocked out”, leading to a requirement for exogenous glutamine.  All characteristics of the CHOK1SV GS-KO™ cell line show good comparability data to our original CHOK1SV™ cell line.

    For fast and convenient cloning of GS vectors encoding antibodies, we offer a range of vectors which include the robust viral promoter, mCMV and contain gene-optimized antibody constant regions. The system also includes full protocols, access to Lonza’s Version 8 (v8) Media and Feeds CDACF Platform and technical support from Lonza’s expert GS Team. 

    Xceed Your Expectations and Reduce Timelines

    Cell line construction, selection and development are critical milestones on the path to first in human studies. The GS Xceed® Expression System creates cell lines up to 6 weeks faster than the original GS Gene Expression System®.

    Time savings is achieved by:

    • Quicker outgrowth of transfectant pools during selection
    • Reduced time for screening and subculture due to no addition of  inhibitor (MSX) after GS selection which also encourages improved cell growth and faster doubling times
    • Fast adaption into Lonza's commercial process


    High Titers and Worldwide Availability

    The GS Xceed® System has been shown to achieve titers of up to 6g/L using Lonza’s v8 Media and Feed Platform Process. Our GS technical specialists have developed this process with your future scale-up needs in mind. In addition, we offer a full line of Cell Line Construction Services using Lonza’s GS Xceed® System for mammalian protein production.

    This advanced expression platform is available for use globally in all major pharmaceutical and biotechnology markets, including Asia.


    Introducing the next stage in the evolution of our

    GS Xceed® Toolbox: GS piggyBac™

    Meet the challenge of complex protein expression with GS piggyBac™ - a unique and versatile cell line engineering technology. Lonza has acquired the exclusive bioprocessing use rights to piggyBac™ IP – a proven transposon-based technology that preferentially targets stable regions of the genome associated with highly expressed genes. The GS piggyBac™ system uses an engineered hyperactive piggyBac™ transposase enzyme to insert GS Xceed® expression vector cargos into the host cell genome with high efficiency.


    Learn more about the new GS piggyBac™ and our launch promotion offer to new and existing GS® license holders by clicking here.

  • Principles of the GS Xceed® System

    Lonza’s GS Xceed® System is based on the use of the glutamine synthetase (GS) gene (GLUL) as a dominant selectable marker to complement a glutamine auxotrophy caused by a lack of endogenous GS in CHOK1SV GS-KO™ cells. Synthesis of glutamine is catalysed by the GS enzyme (glutamate‑ammonia ligase) which utilizes glutamic acid, ammonia and ATP. Glutamine has multiple roles in cell metabolism, particularly as an energy source, protein constituent and as a nitrogen donor in nucleotide biosynthesis.  Therefore, cells that lack a GS gene (e.g. CHOK1SV GS‑KO™ and NS0 host cell lines) have a requirement for exogenous glutamine. The GS gene used in the GS Xceed® System expression vectors, was cloned from CHO cells and is supplied as part of the system components.