Cell Line Characterization

As a drug developer, the first manufacturing regulatory challenge faced is generation of a Master and Working Cell bank. Production must be carried out under Good Manufacturing Practice and requires specialist knowledge both for the manufacturing itself and the extensive biosafety and characterization testing required to release the banks.

Sartorius offers a broad range of services to characterize your mammalian cell banks in accordance with ICH regulatory guidelines (ICH Topic Q 5 D Quality of Biotechnological Products: Derivation and Characterisation of Cell Substrates Used for Production of Biotechnological/Biological Products). Our services comply with global pharmacopeial standards and are performed in facilities accredited by the U.S. FDA as well as the EMA and MHRA.

Ready-to-Use Quality Control Plans support testing and release of cell banks for use in manufacturing programs:

  • Research Cell Bank (RCB)
  • Master Cell Bank (MCB)
  • Working Cell Bank (WCB)
  • End of Production Cell Bank (EoPCB)  
Integrated cGMP Biosafety & Characterization Services

Sartorius has extensive experience in characterization of cell banks used in production of biologic drugs for protein- and viral-based therapies. Sartorius’ QC testing plans meet requirements for mammalian cell bank release and are designed to meet ICH Q5A regulations with assays validated to GMP standards. Ready-to-use testing schemes may be added to existing Drug Development Risk Strategies or customized for the needs of specific programs.

Cell Bank Biosafety Testing and Characterization Packages

The process of cell banking begins with the introduction of a Research Cell Bank (RCB) into the manufacture of a Master Cell Bank (MCB).  

For this to occur, the RCB must be certified at a minimum to be sterile, mycoplasma free and identity assured. Additionally, it may be requested by the manufacturer that a broad-spectrum cell-based in vitro test for potential viral contaminants be performed.  

To expedite RCB release, options include rapid testing by Polymerase Chain Reaction (PCR), interim read in vitro strategies, and identity testing by DNA Barcoding.

Working cell banks (WCB) are prepared from  the MCB. Biosafety testing requirements of the WCB depend upon the level of testing that has been conducted on the MCB. 

Where extensive characterization has already been completed on the MCB, minimal testing is required on the WCB. Depending on the regulatory authority, this is typically limited to assessment of identity, stability and contamination by microbes. Virus testing is only recommended where a recognized risk occurs. 

To characterize genetic stability, the transgene is assessed using techniques such as Southern blotting, sequencing of mRNA and/or transgene copy number. Identity can be measured using DNA barcoding. The presence of microbes is determined using sterility, mycoplasma and mycobacterium assays.

Test methodologies used to characterize working cell banks originating from different species include:

  • Sterility Testing
  • Mycoplasma Testing
  • in vitro assays

Genetic stability assays may be requested using these methods:

  • Nucleic Acid Sequencing
  • Southern Blot
  • Identity Testing
  • Gene Copy Number

An End of Production Cell Bank (EoPCB) is sometimes referred to as a Post-Production Cell Bank (PPCB) or as cells at the limit of in vitro cultivation. These cells are tested to validate the production system. This ensures that the cells are stable and that there are no contamination issues within the system.

The timing of the sampling for an EoPCB will vary between products and is performed on a case-by-case basis.

For cell lines used in the manufacture of protein-based therapies, the testing requirements are two-fold; they include tests for stability and tests for contamination (Biosafety). Testing schemes for cell lines used in viral vaccines or viral vectors may not require the same genetic stability assessments depending on the MCB generation process.

Requirements for the EoPBC are very similar to that for the Master Cell Bank. The EoPCB requires Genetic Stability testing and direct comparison with the MCB. Tests used include genetic analysis of the transgene using techniques such as Southern blotting, mRNA sequencing or transgene copy number. A number of different methods are used to test for potential contaminants including those for microbes (Sterility and Mycoplasma), adventitious virus (in vitro and in vivo, Transmission Electron Microscopy) and specific virus tests, as determined by the process.

Test methodology used to characterize EoPBC originating from different species include:

  • Sterility Testing
  • Mycoplasma Testing
  • in vivo Testing
  • in vitro Testing
  • Retrovirus Testing
  • Bovine and Porcine Assays
  • Electron Microscopy
  • Species-Specific Assays

Genetic stability assays provided by Sartorius include the following:

  • Nucleic Acid Sequencing
  • Southern Blot
  • Identity Testing
  • Gene Copy Number

Cell Bank Testing Requirements

With a safety profile established over 20 years, CHO cells are by far the most used production cell lines in the pharmaceutical industry. Sartorius has performed biosafety and characterization testing on over 200 CHO cell banks. Our scientists have a wealth of experience to advise on the most appropriate and cost-effective testing strategy to meet regulatory requirements.  This recommendation takes into consideration both the history of the cell line and the raw materials used during the manufacture of the bank. Below is a standard QC testing plan for CHO cell line characterization.  While this plan may be modified for cells of human and simian origin, the basic principles apply.

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In vitro assays




In vivo assays



Antibody tests


Retrovirus infectivity



Reverse transcriptase

Electron microscopy



Species specific tests


Table 1: Overview of GMP, GLP Testing Requirement

Related Assets

Brochure: Chinese Hamster Ovary (CHO) Cell Banks Safety

Read Brochure

What is Mycoplasma?

Mycoplasmas are the smallest self-replicating organisms currently known to science.

Read Blog Article

ICH Topic Q5A (R1)

Quality of Biotechnological products: Viral safety evaluation of Biotechnology products derived from cell lines of human or animal origin.

Visit Website

Consult Our Experts

Consult Our Experts

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