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.