Background
Retroviruses are efficient tools for delivering heritable genes into the genome of dividing cells. However,
conventional NIH-3T3 based retroviral packaging cell lines have limited stability and produce low viral
yields, mainly due to poor expression level of the retroviral structure proteins (gag, pol, env) in the
packaging cells.
The Platinum-E (Plat-E) Cell Line, a potent retrovirus packaging cell line based on the 293T cell line, was
generated using novel packaging constructs with an EF1α promoter to ensure longer stability and highyield
retroviral structure protein expression (gag, pol, ecotropic env). Plat-E cells can be kept in good
condition in for at least 4 months in the presence of drug selection, and can produce retroviruses with an
average titer of 1 x 107 infectious units/mL by transient transfection. In addition, replication competent
retroviruses (RCR) are virtually nonexistent because only coding sequences of viral structural genes are
used, avoiding any unnecessary retroviral sequences.