Substitution of transferrin by FeCl3 in the development of a low foetal calf serum concentration medium for KB-26.5 hybridoma cell line

The protection of hybridoma cells from apoptosis by caspase inhibition allows culture recovery when exposed to non-inducing conditions

Programmed cell death (PCD) or apoptosis process in a hybridoma cell line induced by the deprivation of one of the main nutrients, glutamine, has been studied. The use of caspase inhibitors has enabled maintenance of cell viability during a significant period of time, when glutamine depletion was maintained in the culture. Two caspase inhibitors partially suppressed the progress of PCD under glutamine deprivation: Ac-DEVD-cho and z-VAD-fmk. Indeed, as a consequence of this protection, the number of viable cells decreased by 10% (for z-VAD-fmk) and by 80% (for Ac-DEVD-cmk) after 36 h of culture, while it decreased by 90% for a control culture in the absence of protective compounds. However, when the culture was exposed to non-apoptotic conditions after this period of time under apoptosis protection conditions, a normal growth pattern was not recovered. Interestingly, the simultaneous use of both inhibitors made the recovery of the cell culture possible even after a period of 36 h under glutamine depletion, indicating that the inhibition of the effector caspases occurs upstream of the point in which hybridoma cells enter into the commitment step of the death programme.