pCL Vector System: Rapid Production of Helper-Free, High-Titer, Recombinant Retroviruses

Inventors: Inder Verma
Potential Uses: Gene Expression
Maximize recombinant-retrovirus titers in a simple, robust, and flexible experimental system.

Production, cloning, and characterization of helper-free retrovirus vectors takes about two months when conventional murine retrovirus packaging cell lines are used. The pCL vector system includes retroviral vectors and packaging plasmids that produce helper-free retrovirus with titers of 1 X 106 to 5 X 106 within 48 hours. The pCL vectors have been designed to maximize recombinant-retrovirus titers in a simple, robust, and flexible experimental system. By selecting vectors designed to express genes from one of four promoters, the pCL system permits the investigator to control the level of gene expression in target cells over a 100-fold range, while maintaining uniformly high titers of virus from transiently transfected producer cells. The pCL packaging plasmids lack a packaging signal and include an added safety modification that renders them self-inactivating.