Japanese–English glossary
Master cell bank (MCB)
マスターセルバンクmasutā seru banku
Also written マスターセルバンク（MCB）
A homogeneous stock of cells, prepared from a single cloned cell or cell pool under defined conditions, filled into many vials and stored frozen, from which all working cell banks are made. It is characterized under ICH Q5D and tested for adventitious agents under ICH Q5A. In Japan, the raw materials used to create an MCB fall under the Standard for Biological Ingredients, and industry has reported that details for older banks are hard to obtain. An MHLW administrative notice of 2009 on MCBs not meeting the standard was abolished in March 2026, when the standard's operating rules were revised.