New media and their advantages in the production of suspended cells and foot--and--mouth disease virus.

The problems related to the use of serum in cell culture are reviewed. The possibility of substituting the serum with peptones has already been shown. Different peptones have been tested: one of the best is a peptone obtained from meat and casein pepsin pancreatically digested. BHK 21/13 cells were cultivated in serum-free media for 35 passages. The 0.81 cultures without automatic pH control had a cycle length of 3 days; starting with concentrations of 0.4 X 10(6) cells/ml, concentrations higher than 3 X 10(6) cells/ml were often obtained. We did not obtain satisfactory results when the volume of cultivation was increased to more than 6 1, perhaps because of different requirements for agitation, pH, O2. It is also necessary to check whether the results obtained up to now are consistent with reference to the source of reagents and cell strain used. The absence of serum in the medium did not influence virus replication when infectivity and complement fixation titers were tested.