CHARACTERIZATION OF 911 - A NEW HELPER-CELL LINE FOR THE TITRATION AND PROPAGATION OF EARLY REGION-1-DELETED ADENOVIRAL VECTORS

Currently, the preferred host for the production of early region-1 (E1 )-deleted recombinant adenoviruses (rAdV) is cell line 293, which was generated by transformation of human embryonic kidney cells by sheared adenovirus 5 (Ad5) DNA. To develop alternative hosts for the producti on of rAdV, we generated adenovirus-transformed human cell lines by tr ansformation of human embryonic retinoblasts (HER) with a plasmid cont aining base pairs 79-5789 of the Ad5 genome. One of the established HE R cell lines, which we called 911, exhibited favorable growth characte ristics and was chosen for further study. This cell line is demonstrat ed to have several characteristics in common with the well-known 293 c ell line: The 911 cell line is highly transfectable, and exhibits simi lar frequencies of homologous recombination. However, it has additiona l characteristics that make it a useful alternative for 293. The 911 c ells perform particularly well in plaque assays. Upon infection with E 1-deleted adenoviruses, plaques become apparent in monolayers of 911 c ells already after 3-4 days versus 4-10 days in monolayers of 293 cell s, thereby reducing the time required for quantitative plaque assays. Furthermore, yields of E1-deleted adenovirus vectors up to three times as high as those achieved with 293 cells can be obtained with 911 cel ls. Finally, the Ad5-DNA content of the 911 cell line is completely kn own. These features make the 911 cell line a useful alternative for th e construction, propagation, and titration of E1-deleted recombinant a denoviruses.