Master Cell Bank (MCB)

Master Cell Bank (MCB) designates a fully characterised homogeneous suspension of cells stored in multiple identical aliquots under defined cryopreservation conditions, serving as the primary source from which all subsequent manufacturing cell cultures derive, ensuring consistent production of biopharmaceutical products throughout the commercial lifecycle. This foundational inventory establishes traceability from original cell source through final drug product, with extensive characterisation confirming identity, purity, freedom from adventitious agents, genetic stability, and productivity.

MCB generation begins with isolating or creating a single cell clone exhibiting desired characteristics including high productivity, genetic stability, and appropriate post-translational modifications, which undergoes expansion through defined passages creating sufficient biomass for cryopreservation in numerous individual vials stored in multiple ultra-low temperature freezers providing redundancy. Comprehensive testing characterises MCB contents confirming cell line identity, transgene presence and sequence, expression levels and product quality, plus extensive testing for microbial contaminants. Working Cell Banks derived from MCB vials support routine manufacturing. Regulatory submissions include detailed MCB characterisation data, generation procedures, testing results, and storage conditions. Change control procedures govern MCB modifications, requiring extensive comparability studies when replacing MCBs demonstrating new banks produce equivalent products. As biologics manufacturing expands and regulatory expectations increase, MCB development and management remain foundational quality assurance elements ensuring consistent, safe therapeutic protein production.