Recent trends in cell substrate considerations for continuous cell lines

Product development activity in the past five to ten years has reconstituted a version of an old debate on the safety assessment of biological products, namely whether the use of some types of continuous cell lines (CCLs) is appropriate in the preparation of some types of biological products. Since 1987, dozens of purified recombinant DNA products derived from CCLs have been developed and have received regulatory approval. In addition, several live attenuated and inactivated viral vaccines manufactured in CCLs were approved after thorough review of product safety and manufacturing issues. The current discussion revolves around the potential use of CCLs (human or not) to prepare purified protein subunit vaccines, such as for HIV, and the use of human CCLs to prepare purified protein products.