An Alternative Method for the Rapid Generation of Stable, High-Expressing Mammalian Cell Lines

Abstract

Biopharmaceutical companies are constantly evaluating new methods for mammalian cell line development that offer any of the following benefits: shorter time lines, improved consistency, higher production, better genetic stability, and increased flexibility. Each of these advantages extends a large cost benefit to companies as their recombinant protein products are moved from development into the clinic and finally to commercial launch. A versatile system has been developed that is capable of transferring genes of interest into a wide variety of mammalian host cells and offers a number of the above advantages over other methods. The system, which is referred to as GPEx™ (an acronym for “gene product expression”), utilizes replication-defective retroviral vectors, derived from Moloney murine leukemia virus (MLV) and pseudotyped with vesicular stomatitis virus G protein (VSV-G), to stably insert single copies of genes into dividing cells. Retrovectors deliver genes coded as RNA that, after entering the cell, are reverse transcribed to DNA and integrated stably into the genome of the host cell. Two enzymes, reverse transcriptase and integrase, provided transiently in the vector particle, perform this function. These integrated genes are maintained through subsequent cell divisions as if they were endogenous