Considerations for cell passaging in cell culture seed trains

Background The purpose of a seed train is the generation of an adequate number of cells for the inoculation of a production bioreactor. This is timeand cost-intensive. From volumes used for cell thawing or cell line maintenance the cell number has to be increased. The cells are usually run through many cultivation systems which become larger with each passage. The seed train steps have a significant impact on the product titer and cell growth in production scale, as well as the success and the reproducibility of the seed train itself. Furthermore, cell line changes in the existing facility require adaptions of the seed train protocol. The design of a new facility involves the choice of the optimal seed train scales in order to meet the future requirements of the cultivated cell lines.