Application of a serum-free medium for the growth of vero cells and the production of reovirus

Two strains of reovirus (serotype 1 Lang/TIL and serotype 3 Dearing/T3D) we re propagated in Vero cells grown in stationary or agitated cultures in a s erum-free medium, M-VSFM. Solid microcarriers (Cytodex-1) were used to supp ort cell growth in agitated cultures with a normal doubling time of 25 h. C ell yields of 1 x 10(6) cells/mL were obtained from an inoculum of 2 x 10(5 ) cells/mL in 4 days in microcarrier cultures. The growth profile and cell yield was not significantly different from serum-supplemented cultures. The virus titer increased by 3-4 orders of magnitude over a culture period of 150 h. The maximum virus titer in stationary cultures reached >1 x 10(9) pf u/mL for both strains of reovirus in M-VSFM. M-VSFM also supported high vir al yields in microcarrier cultures. Both the specific productivity and fina l viral yield was higher in M-VSFM than serum-supplemented cultures. The hi gh viral productivity suggests that this is a suitable system for the produ ction of reovirus as an oncolytic agent for human therapeutic use.