The use of foetal, calf and adult bovine sera for the growth of serially subcultivated diploid cells.

Medium CMRL-1969 supplemented with either foetal calf, calf or adult bovine sera, or a combination of the various sera, was used to subcultivate diploid cells for the preparation of substrates for vaccine production. Supplementation with calf or adult bovine sera gave satisfactory cell yields for at least 3-4 population doublings. The finite lifespan of the diploid cells grown in media supplemented with foetal calf was always longer than with calf or adult bovine sera. However, a combined supplement of adult serum plus a low concentration of foetal calf serum gave results equally as good as foetal calf serum alone. Sera obtained aseptically from adult animals kept in isolation and monitored constantly for health are more desirable than sera obtained from abattoirs. Selection of donor animals and pooling of certain serum batches were found to be important for the preparation of serum supplements. The final protein concentration of the cell culture medium should not exceed 0.8% when adult bovine sera are used. For the growth of WI-38 or MRC-5 cells the use of foetal calf serum can be reduced or eliminated.