Monitoring growth and death of Vero cells cultivated in bioreactor with serum-containing and serum-free media

The density of viable cells in culture results from a balance between cell proliferation and cell death. The aim of this study was to characterize and compare these two phenomena in Vero cell cultures in one serum containing medium (ScA) and one serum free medium (SfB) in bioreactors. ScA supported a higher maximal viable-cell density (2.3 x 10(6) vs. 1.8 x 10(6) cells/ml). However, cell-cycle analysis showed that cell division was more active in SfB than in ScA. LDH release in the Supernatant increased much earlier in SfB than in ScA (one vs. five days), but trypan blue counts showed no apparent difference in the viability of the cultures. Apoptosis, evidenced by annexin V-FITC/PI staining, could be detected in the population of suspension cells detached from microcarriers, but not among adherent cells; positivity of the TUNEL assay occurred later than that of the annexin V-FITC/PI staining. Our data indicate that the lower cell yield in SfB, compared with that in ScA, results from a higher cell death rate. Apparently, cells die mostly from apoptosis.