QualiCell? 293A Cell Line is a subclone of the 293 Cell Line and has a relatively flat morphology. It facilitates the initial production, amplification and titering of replication-incompetent adenovirus. The cell line contains a stably integrated copy of the E1 gene that supplies the E1 proteins (E1a and E1b) required to generate recombinant adenovirus. The flat morphology of the cells makes the titering procedure easier.