New advanced protein-free, animal component-free medium for recombinant protein expression in adherent CHO cell cultures

As more and more recombinant proteins are being used as therapeutic agents, the methods employed in their production are coming under increasing regulatory scrutiny, One of the areas of regulatory concern is the presence of animal-derived components in the media used to grow cells for recombinant protein expression. A CHO Protein-free Animal Component-free Medium (Sigma C5467) was previously developed to support suspension culture and to achieve the desired recombinant protein expression. In order to extend the usage of this medium to the adherent cell culture systems, such as roller bottles and fluidized bed bioreactors, we recently developed a CHO Protein-free Animal Component-free Attachment Medium (Sigma C8730). Our data indicates that recombinant CHO cells growing in T-flasks or roller bottles with this attachment medium exhibit similar cell growth and a higher level of recombinant protein expression as compared to cells grown in DME/F12 supplemented with 10% fetal bovine serum. Moreover, CHO cells growing in suspension culture with Sigma C5467 medium can be directly transferred to T-flasks or roller bottles with C8730 medium for a short-term adherent culture without a pre-adaptation step. Besides CHO cells, various cell lines including HEK293, Vero and C127 can be maintained as adherent cultures in the Sigma C8730 medium with some modification and supplementation with appropriate recombinant growth factor(s). This observation strongly indicates that this new medium might be a good basal medium for any customers specific cell line grown as adherent cultures. Finally, the performance of this medium (Sigma C8730) for CHO single cell colony isolation for the selection of new recombinant protein expressing cell lines is contrasted with serum-containing media commonly used for this procedure.