Growth of 293 cells in suspension culture

A subline of 293 cells able to grow in suspension culture has been developed by passage of 293 cells through nude mice. This new line, designated 293N3S, grows with a doubling time of approximately 30h, continues to express adenovirus 5 early region 1 (E 1) antigens, and remains permissive for adenovirus 5 host range mutants defective in E1 functions. The human adenovirus 5 (Ad5)-transformed human embryonic ell line 293 (Graham et al., 1977) has proven useful for a number of purposes. Because the cells contain the left end (the transforming region) of the Ad5 genome and express early region 1 (E 1) they are permissive for growth of Ad2 and Ad5 mutants that are defective in E 1 functions. Thus 293 cells are extensively used for the isolation and propagation of E1 mutants (for review, see Young et al., 1984). Because they permit the growth of mutant viruses from which the entire E1 region has been deleted, thus providing a non-essential region f r DNA insertion as well as increasing the potential size of DNA inserts (Haj-Ahmad & Graham, 1986), 293 cells are likely to be extensively used in the development of adenovirus as helper-independent cloning and expression vectors in mammalian cells (see Berkner & Sharp, 1984; Van Doren et al., 1984; Haj