ProteoGenix strives to overcome the economic issues related to stable cell line generation by offering the most productive IP free cell lines on the market. With a one-time fee and strong yield guarantees, our stable cell line development service, based on our proprietary cell line, aims at offering high productivity at competitive price and FTO without royalties! ProteoGenix also offers all other most common cell lines to perfectly meet your project requirements!

ProteoGenix strives to offer best-in-class services from target selection to bioproduction. Our unique knowledge of the whole process, combined with our expertise in monoclonal antibody development and protein production, is your best guarantee to obtain a high producing stable cell line.

As a major player in the therapeutic antibody development field, bringing your biotherapeutic from the bench to the clinic is our challenge. Let us support your stable cell line development project and pave the way to success!

Discover our stable cell line development service content

Expression vector construction

  • Gene synthesis optimized for the target expression system.
  • Gene subcloning in a high performing expression vector.

Host cell transfection and generation of stable pools

  • Transfection of the host cells with the recombinant plasmid.
  • Generation and characterization of several stable transfected pools.

Characterization of the best stable pools

  • Selection and amplification of the most producing stable pools for further clone selection
  • .


Isolation and selection of the best monoclones

  • Isolation of monoclones by limiting dilution.
  • Screening by ELISA, WB, FACS, IP or Octet Red96.
  • Selection and expansion of the most producing clones.

Characterization of the best monoclones

  • Productivity evaluation in batch and/or fed-batch culture
  • RCB preparation and stability study

Upstream process optimization

  • Test of several culture medium and several feed strategy (media/culture optimization).

Stable cell line and protocol transfer



Step Content Timeline Deliverables
Gene synthesis
  • Gene design including codon optimization
  • Gene synthesis
  • Subcloning in expression vector
3 to 4 weeks
  • Gene optimized for the required expression system
  • Gene cloned in pUC57 plasmid
Stable pool generation
  • Stable transfection
  • Pool selection and amplification
9 to 10 weeks
  • 50mL of the supernatant from stable pool
  • Stable pool vials
  • Detailed report
Single cell clones screening and subcloning
  • Subcloning of the top producing clones
  • Characterization of clones
  • Stability study
  • RCB preparation
~4 months
  • Research cell bank -tested for Mycoplasma
  • Certificate of Analysis
  • Detailed report
Process optimization
  • Test of several media/feed conditions
4 to 5 weeks
  • Detailed report
  • Optimized protocol transfer


  • PoC based on transient expression evaluation before to start
  • Additional characterization (KD determination, thermostability, aggregation…)
  • RCB stability study
  • Master and working cell bank development
  • Scale up production / Bioreactor

Available cell lines

Proprietary CHO

  • Freedom to operate (one-time fee payment)
  • MTX/DHFR-mediated amplification and selection


  • Methionine Sulfoximine (MSX)/GS-mediated amplification and selection
  • Rapid and easy transfer for cGMP production


  • No Licence fee before moving towards commercial use
  • MTX/DHFR-mediated amplification and selection


  • Methionine Sulfoximine (MSX)/GS-mediated amplification and selection


  • No Licence fee before moving towards commercial use
  • MTX/DHFR-mediated amplification and selection
  • Used for the bioproduction of FDA-approved biotherapeutics

Proprietary GS-

  • Yields > 5-6g/L
  • Limited license fees
  • Highly efficient GS-mediated clone amplification and selection
  • Rapid and easy transfer for cGMP production

Other cell lines available

  • HEK293, 293F, 293E
  • Customer cell line

As each stable cell line generation project is unique, our service is tailored to meet your requirements and to ensure a safe investment. Send your requirements to our PhD account managers who will put together a customized offer. Our stable cell line development service is composed of several milestones (Go/ No Go steps) that are accompanied by a detailed report and discussed with our expert team. By building your your project in this way, you can be guaranteed of support throughout the development process giving you unique flexibility.

Have you not successfully achieved a high antibody transient expression yield? Then carry out a transient expression evaluation on our best-in-class high producing proprietary CHO cell line XtenCHO™.

Our XtenCHO™ cell line together with our in-house Xten Protocol is your best chance at overcoming your difficult-to-express protein challenge. This is usually the first step before moving to stable cell line development in order to be able to ensure that all antibody features meet the requirements in CHO based productions.

We maximize your chance to get a high producing stable cell line at competitive price

As a contract research organization (CRO) having successfully produced more than 1500 recombinant proteins and 300 monoclonal antibodies, ProteoGenix constantly strives to offer innovative tools to satisfy and even exceed its customer’s requirements. Proposing a high performance cell line at competitive price is one of our daily challenges. For this reason, a team of dedicated R&D experts is currently working on the development of one of the most productive GS deficient cell line on the market.

Do you need to develop a highly productive stable cell line? Try our customized stable cell line development service.

Metabolic selection and amplification for stable cell line generation

Selection of highly productive stable cell clones is of primary importance when it comes to stable cell line development. For several decades now, metabolic selection has become the preferred method to select the most productive clones for bioproduction. This field is characterized by intense research activity due to the important economic issues related to the production of biotherapeutics. Overcoming this challenge means reducing production costs by increasing the productivity of stable cell lines, while reducing their development timelines. Metabolic selection is based on the disruption of a vital metabolic pathway. In the biopharmaceutical industry, the enzymes glutamine synthetase (GS) and dihydrofolate reductase (DHFR) are the most commonly used selectable markers for the disruption of metabolic pathways. GS and DHFR are involved in the synthesis of the vital metabolites glutamine and purines, respectively.

When using a metabolic selection strategy, the stable clone selection process is based on cell culture in a medium lacking the vital metabolite. Thus, only the cells able to endogenously produce the target metabolite will be able to survive in the culture media. In expression systems lacking DHFR or GS activity, endogenous production of the vital metabolite is only possible for cells stably transfected with a plasmid containing the GS or DHFR gene. This selection process can further be amplified by the addition of DHFR or GS inhibitors such as MTX or MSX, respectively. Gradually increasing inhibitor concentration leads to gene amplification in order to overexpress GS or DHFR. Therefore, since the marker gene is linked to the recombinant protein gene to express (both genes on the same plasmid), recombinant protein production is amplified in the same proportion as the marker production.

As a protein production expert, ProteoGenix masters all the steps of the process leading to a highly productive and stable CHO cell line. Together with our FTO cell line and unrivalled guarantees, our expertise ensures you a safe investment and a strong ROI.