Cell banking.

The use of cultured cells (diploid strains or continuous cell lines) to produce biopharmaceuticals provides a level of standardization to the manufacturing process that cannot be attained by the more traditional methods of biological extraction from animal or human fluids, tissues, or primary cells. The key to this advantage is the ability to cryopreserve the production cell line as a master cell bank. This bank serves as the common starting source of a given product for the lifetime of the manufacture of that product. Since the MCB is the common and only starting source, it can be exhaustively characterized with regard to contamination by adventitious and endogenous agents. Assays can be developed for cellular components that are potential contaminants of the product. The removal of these components during product purification can be validated and their removal confirmed by rigorous quality control. In conclusion, characterized cell banks are central to the standardization of biopharmaceutical manufacturing processes and give rise to the production of high-quality products not attainable by the traditional methods of extraction of product from sources which are continually changing.