Cell Banking

Leinco Technologies offers a variety of cell banking services including preparation of both master cell banks (MCBs) and working cell banks (WCBs). Leinco is a custom manufacturer of monoclonal antibodies and proteins for diagnostics and In vivo preclinical research.  Leinco is ISO 9001:2015 certified and compliant with Good Manufacturing Practices (GMP). This assures Leinco’s products are consistently produced and controlled according to quality standards. Leinco’s cell culture and protein production facility handles both large and small-scale production of was specifically designed and built for the production of monoclonal antibodies and recombinant proteins.

What’s the difference between MCB and WCB?

The master cell bank is created from a single cell source optimized for monoclonal antibody production. Cells are expanded to a level required to freeze an appropriate number of vials based on demand for their use. Master cell banks are tested for recovery viability after cryopreservation. A master cell bank is biosafety tested and the cell line is authenticated. The scope of biosafety testing and authentication is determined based on the client-specific application and advice from the worldwide regulatory bodies.

The working cell bank (WCB) is created from the expansion of a master cell bank vial. Expansion and cryopreservation of the working cell bank depends on the demand for use. It is the working cell bank that is used by cell culture manufacturing scientists to produce the seed culture for inoculation of bioreactors. Leinco Technologies offers custom In vitro Antibody and Protein Production in stirred tank and hollow fiber bioreactors.

The first step in a quality manufacturing system is to assure creation of master cell banks (MCB) and working cell banks (WCB). Leinco Technologies uses a tiered cell banking system to ensure a consistent supply of characterized cells for use in continuous cycle manufacturing campaigns. Cell banking work is performed in dedicated cleanroom suites using standard operating procedures and data from the preparation of cell banks is recorded in detailed batch records.

Mycoplasma (-) Negative Testing

As part of the master cell banking and working cell banking process, all cell lines are tested and certified to be mycoplasma negative (-). Mycoplasma are a group of bacteria that lack a cell wall around their cell membrane making them resistant to most antibiotics. The presence of mycoplasma in a cell culture could induce cellular changes including chromosomal aberrations, changes in metabolism and cell growth.

This certification is necessary to not only prevent the contamination of other cell lines during the cell culture process, but to avoid the detrimental effects mycoplasma contamination may have on protein or antibody expression. It is estimated that 15% of US labs and up to 60% of Asian Labs are contaminated with mycoplasma. The top 5 reasons and benefits to test and certify your cell lines are as follows:

  1. Worldwide estimates are 35% of existing cell banks may be contaminated
  2. Loss of engineered cell lines that took many months or years to create
  3. Major impact on data reliability and reproducibility
  4. Testing is required by many journals for publication and by regulatory agencies
  5. Loss of financial resources such as grants dependent on specific cell lines

It is the policy of Leinco Technologies to thaw all cells in a quarantined clean room suite. All incoming vials are tested for mycoplasma contamination while in quarantine. If the initial mycoplasma test is negative, the cell line will be expanded for potential cryopreservation of sufficient back up vials.

Clonality and Productivity Testing

To determine if a cell line is optimal for In vitro production of monoclonal antibodies, a clonality and specific productivity rate (SPR) assay should be performed to determine the percentage of cells in the culture producing antibodies of a similar titer. To maximize monoclonal antibody production, a cell line optimization procedure should be performed during the creation of a master cell bank (MCB). If a cell line optimization procedure is not performed, non-producing cells may be selected over antibody producers in the bioreactor or during adaptation to protein free, animal origin free media.

Cell Line Optimization

Using the limiting dilution cloning technique, parental cell cultures are cloned and tested for antibody production. After each round of limiting dilution cloning, cells are tested for antibody production and the results are analyzed using a statistical method to determine when the cell line is optimized for In vitro production of monoclonal antibodies.


Mammalian cell lines including CHO, NSO, HEK-293 and hybridomas may be adapted for cell culture in chemically defined, protein free, animal origin free medium. Bioreactor production of recombinant proteins and antibodies is routinely carried out in a protein free environment. This often facilitates downstream processing procedures assuring that the final product is manufactured in an animal origin free system.


A critical part of manufacturing monoclonal antibodies and proteins is the generation and cryopreservation of the MCB. This assures consistent quality production well into the future. MCB is prepared by performing multiple rounds of single cell cloning and testing until the cells are optimized for production and safe for cryopreservation. Upon agreement of the appropriate scope of work, cell banks are prepared according to guidance established by international regulatory agencies such as the FDA, USDA or EMEA.  Each cell bank prepared is tested for mycoplasma and sterility. Testing for adventitious agents is dependent on the final application for each cell bank. The exact number of vials to be cryopreserved is dependent on regulatory guidelines and future production requirements.