Continuous Cell Substrate Considerations
Few issues regarding the development of cell culture biologicals have been debated as long or as vigorously as the use of continuous cell lines (CCLs) as substrates. This chapter describes the scientific tools available to evaluate the putative risk of tumorigenicity due to potential virus DNA and protein contaminants. The evidence of tumorigenic potential from contaminating DNA comes from several sources. The DNA of any of several transforming viruses in vivo, such as SV40, polyoma, and herpesvirus samiri, are capable of tumorigenesis when their complete genome was provided in suitable form to susceptible biological host. Retroviruses may be transmitted biologically by either of two means: horizontally from an infected individual to a susceptible one by an infectious virion (like classical adventitious agents) or vertically from one generation to the next via a DNA copy of the viral genome covalently linked to the host genome.