The 293 cell line is a permanent line established from primary embryonal human kidney transformed with sheared human adenovirus type 5 DNA (Graham et al., 1977; Harrison et al., 1977). The E1A adenovirus gene is expressed in these cells and participates in transactivation of some viral promoters, allowing these cells to produce very high levels of protein.
The FreeStyle 293-F cell line is a clone of the 293 cell line and is intended for use with the FreeStyle 293 Expression System. These cells are adapted to suspension culture in FreeStyle 293 Expression Medium.
The 293H cell line was also cloned from 293 cells, and like 293F cells can be grown as either suspension or adherent cultures. Neither 293F or 293H attach very well in SFM. In serum-supplemented medium, both attach better, but 293H attaches better than 293F. 293H is also better for transient transfection. 293F cells have a faster doubling time than 293H, and are better suited for selection of stables and large scale cultures.
The 293FT Cell Line is derived from the 293F Cell Line and stably expresses the SV40 large T antigen from the pCMVSPORT6TAg.neo plasmid. Expression of the SV40 large T antigen is controlled by the human cytomegalo-virus (CMV) promoter and is high-level and constitutive.