Cell banks and stability of antibody production

The original and fundamental appeal of monoclonal antibodies (mAbs), compared with polyclonal antisera, is the possibility for indefinite production of the same product. However, even well-established cell lines have limited stability in long-term culture and it is necessary to establish a control system to ensure continuity of product supply. This is normally done by a seed lot system. A pool of cells derived from a single clone is frozen in a number of vials (say 100) to create a master cell bank (MCB). This MCB is carefully stored in liquid nitrogen. As required, individual vials are thawed and expanded to provide working cell banks, which might also consist of about 100 vials. Thus up to 10,000 production runs can be initiated before the original cell stock is exhausted. Obviously the number of vials in a bank can be adjusted to meet individual requirements. Working cell banks may not be necessary for experimental or preclinical projects, but you should at all costs avoid depletion of a clinically important master cell bank.