New technologies and challenges of novel virus detection.

The use of new cell substrates for the development of biologicals, particularly tumorigenic and tumor-derived cell lines, can pose a major regulatory challenge due to safety concerns related to the presence of novel viruses, latent and occult viruses including oncogenic viruses, and endogenous retroviruses, since these may not be detected by the currently recommended conventional assays. This report is a summary of our laboratory's experiences using advanced nucleic acid-based technologies to evaluate a Madin-Darby canine kidney (MDCK) cell line and the insect Sf9 cell line derived from Spodoptera frugiperda, and presents some ongoing efforts to address the challenges of novel virus detection.