Escherichia coli cell bank: development, characterization, and transfer for biopharmaceutical medicines production (review)

Introduction. Biological medicines produced using recombinant DNA technology play an important role in the international pharmaceutical market. Currently, bacterial and mammalian expression systems are widely used to produce recombinant proteins, monoclonal antibodies, and vaccines. To maintain the quality and stability of inoculation, cell banks are generated. Text. The general recommendations for cell bank development are outlined in the ICH Q5 guidelines. In the Russian Federation, similar requirements are specified in Decision No. 89 of the Council of the Eurasian Economic Commission "On approval of the Rules for assessments of biological medicines in the EAEU". Based on these requirements, one- or two-level cell banks should be established. Initially, a Master cell bank (MCB) is generated from a well-characterized single-cell bacterial colony according to high-quality standards. Subsequently, a Working cell bank (WCB) is created from one or several well-characterized MCB cryovials. As a result, the number of parameters required for WCB characterization can be reduced. The identity, purity, and stability of the cell bank should be determined. Requirements for cell bank characterization are detailed in official guidelines. An identity test is used to confirm the cell line or strain identification, which is a critical step to prevent cross-contamination and ensure the correct cell line in manufacturing processes. The absence of bacterial, fungal, or other types of contamination is demonstrated through purity testing. The sterility test is a key component, ensuring that a pure cell is used. The stability test demonstrates the genetic stability of the cells, including the preservation of genetic characteristics and the monitoring of harmful mutations during cultivation processes. Comprehensive data on the cell bank history, development, and characterization should be provided during its transfer. Conclusion. This research presents the general concept of microbial cell bank development, characterization, and transfer based on bacterial expression systems.