Proteos offers mammalian cell expression for production of proper post-translationally modified recombinant proteins.  Post translational modification is often required for efficient secretion and function and is preferred in downstream applications that require biologically functional protein.

Our industry leading transient expression platform utilizes fully licensed HEK (human embryonic kidney) and CHO (Chinese hamster ovary) cells lines expressing the Epstein-Barr virus (EBV) nuclear antigen 1, with proprietary expression vectors containing the EBV origin of replication (OriP) to allow episomal plasmid amplification and high level recombinant protein expression.

We utilize optimized and fully validated mammalian cell expression protocols for consistent, reproducible protein expression in serum-free shake flask culture volumes ranging from 30 mL to 60 L per batch.   Only mycoplasma-free, high viability, low passage cultures are used for transfection and are monitored using a Beckman Coulter Vi-CELL TM XR for culture density, viability, and average cell diameter.  The Vi-CELL TM XR uses the trypan blue dye exclusion method and averages 50 measurements to compute the parameters for each sample.  This allows us to monitor cultures with a high degree of accuracy which is imperative for quality and reproducibility of protein production projects.  All cell culture data is included in a customized technical report delivered with each project.

Typical productions times are 4-6 weeks for construct design, expression, and purification.  

Services offered:

  • Proteos offers a full suite of molecular biology services to accompany any of our expression platforms.  Molecular biology services available include construct design, fusion partner and affinity tag selection, gene synthesis with codon optimization, subcloning, endotoxin-free plasmid isolation, and sequence verification.
  • Small-scale expression verification and optimization in scales less than 100 mL scale, ideal for expression testing of multiple recombinant protein targets.
  • Analytical production and yield determination at scales less up to 4 L, ideal for process verification through purification prior to large-scale production.
  • Transient expression of recombinant proteins in HEK293f, HEK293-6E, CHO-S, or CHO-3E7 cells up to 60 L per batch in shake flasks.
  • Delivery of cell paste, conditioned culture supernatant, concentrated buffer-exchanged culture supernatant, membrane preparations
  • Mammalian cell expression services can be combined with Proteos’ purification services for a fully-customized production process.
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