Protein-free culture of Vero cells: a substrate for replication of human pathogenic viruses.

A protein-free chemically defined medium designated PFEK-1 was developed for culture of VERO cells on polyvinyl formal (PVF) culture surface without serum or other macromolecular supplements. VERO cells proliferated in PFEK-1 medium on PVF surface to a similar extent as cells in serum-supplemented medium without previous adaptation from serum-containing conditions. The protein-free culture infected with coxsackievirus B4, herpes simplex virus types 1 and 2, measles virus and poliovirus types 1, 2 and 3 developed viral titers comparable to those found in conventionally grown cells. The results demonstrated that VERO cells in protein-free culture provide a sensitive substrate for the production of human pathogenic viruses which are not contaminated by serum or other protein factors usually added to a culture medium.